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06/11/12




 Chemistry Unit    C1 –
Chemistry in our   World
        EdExcel
06/11/12
                     Elements
If a solid, liquid or gas is made up of only one type of
atom we say it is an element. For example, consider a
tripod made up of iron:




                                       These atoms are
                                       ALL iron – there’s
                                      nothing else in here
06/11/12
                    Compounds
Compounds are
different to
elements. They
contain different
atoms. Here are
some examples:            Methane
                                       Sodium
                                    chloride (salt)




                Glucose
06/11/12
    Some simple compounds…


                                Carbon
Methane, CH4   Water, H2O    dioxide, CO2

                                  Key
                                Hydrogen

                                Oxygen
Ethyne, C2H2
                Sulphuric       Carbon
               acid, H2SO4
                                Sulphur
Balancing equations
                                                         06/11/12



Consider the following reaction:

    Sodium + water           sodium hydroxide + hydrogen



                                        Na
  Na   +        O                                +
                                             H       H      H
           H        H               O




    This equation doesn’t balance – there are 2 hydrogen
    atoms on the left hand side (the “reactants” and 3 on
    the right hand side (the “products”)
Balancing equations
                                                                    06/11/12



We need to balance the equation:

    Sodium + water              sodium hydroxide + hydrogen


                                           Na
                   O                                H
  Na         H         H               O

         +                                                  +
                   O                           Na               H     H
             H         H                                H
  Na
                                           O


       Now the equation is balanced, and we can write it as:

             2Na(s) + 2H2O(l)         2NaOH(aq) + H2(g)
Some examples
                                                      06/11/12




     2 Mg        +   O2   2 MgO
        Zn   + 2 HCl          ZnCl2    +    H2
     2 Fe    + 3 Cl2      2 FeCl3

    NaOH     +
             HCl              NaCl    +    H 2O
      CH4 + 2 O2              CO2     + 2H2O
      Ca + 2 H2O              Ca(OH)2      +     H2
2                                            2
 NaOH    +   H2SO4            Na2SO4       + H 2O
  2            3          2             4
CH3OH    +   O2               CO2     + H 2O
Hazard signs to learn…
                              06/11/12




 Acid       Corrosive     Toxic




        h         i

Harmful     Irritant    Oxidising
06/11/12
Topic 1 – The Earth’s Sea and Atmosphere
06/11/12
            The Earth’s Atmosphere
For the last 200 million years the atmosphere has remained roughly the
same – it contains 78% nitrogen, 21% oxygen, 1% noble gases and about
0.03% CO2
 Carbon dioxide, water vapour     Oxygen      Nitrogen     Noble gases
06/11/12
    Evolution of the Earth’s Atmosphere
  Carbon          Methane       Ammonia         Oxygen          Nitrogen       Others
  dioxide
                                       Present day
                                       atmosphere contains
                                       78% nitrogen, 21%
                                       oxygen, 1% noble
                                       gases and about
                                       0.03% CO2



4 Billion years     3 Billion years   2 Billion years    1 Billion years   Present day
06/11/12
    Evolution of the Earth’s Atmosphere
Volcanic activity
                                          Some of the oxygen is
releases CO2, methane,
                                          converted into ozone.
ammonia and water                         The ozone layer blocks
vapour into the                           out harmful ultra-violet
atmosphere. The water                     rays which allows for the
vapour condenses to                       development of new life.
form oceans.



4 Billion years    3 Billion years   2 Billion years   1 Billion years   Present day

                  Green plants evolve which take in CO2 and give
                  out oxygen by photosynthesis, increasing the
                  amount of oxygen in the atmosphere. Carbon
                  from CO2 becomes locked up in sedimentary
                  rocks as carbonates and fossil fuels and is
                  dissolved into the sea. Methane and ammonia
                  react with the oxygen and nitrogen is
                  released.
06/11/12
  Carbon dioxide in the atmosphere
The amount of CO2 in the atmosphere is affected by 3 things:
               1) Geological activity moves carbonate rocks deep into
               the Earth and they release ______ _______ into the
               atmosphere during volcanic activity.


   2) Human activity - When fossil fuels are burned
   the carbon contained in them reacts with _____
   to form CO2. Furthermore, deforestation means
   that less _____ are around to take in CO2.


           3) Increased CO2 in the atmosphere causes a reaction
           between it and _______. These reactions do not remove ALL
           of the new CO2 so the greenhouse effect is still getting
           _______!

        Words – oxygen, seawater, carbon dioxide, worse, trees
06/11/12
Topic 2 – Materials from the Earth
What are rocks?
                                                      06/11/12


Rocks are made from a combination of minerals and can be
hard or soft depending on how the minerals are arranged.

       Rocks can be
       found here…



          …and here…


            …and here…


              …and here
Sedimentary rocks
                                        06/11/12




Sandstone                   Limestone

            Chalk



             Conglomerate
Sedimentary rocks
                             06/11/12


             How sedimentary
             rocks are formed:


         1) Weathering



         2) Transportation



         3) Deposition



         4) Burial
Metamorphic rocks
                                 06/11/12



       Quartzite




                        Slate



           Marble (made from
           chalk or limestone)
Metamorphic rocks
                                                    06/11/12


Metamorphic rocks are formed by the combined effect of
heat and pressure on other rocks:

  Pressure from rocks above…

 …and heat from magma nearby
Igneous rocks
                               06/11/12




                            Obsidian
Granite




   Pumice
Igneous Rock
                                                                   06/11/12


                        Granite – a slow cooling
                        rock with big crystals
                        and rich in silica


                             Rhyolite – a fast cooling
                             rock with small crystals
                             and rich in silica

                                          Gabbro – a slow cooling rock with
Basalt – a fast cooling rock with         big crystals and rich in iron
small crystals and rich in iron
Igneous rocks
                                  06/11/12



Igneous rocks
are formed
when lava or
magma cools
down and
solidifies


     If the lava or magma cools
     QUICKLY it has SMALL crystals



     If the lava or magma cools
     SLOWLY it has BIG crystals
Summary
                                                                              06/11/12


Sedimentary, igneous or        How they were formed                 Appearance
     metamorphic?

      Sedimentary           Small pieces of sediment       Usually soft, can contain
                            were ______ together by        ________, easily eroded
                            salt and pressure from rocks
(e.g. sandstone, _______,
                            above
           chalk)

                            Liquid rock (______ or lava)   Contain ______, very hard,
         Igneous
                            cooled down and turned back    never contain fossils
                            into a ______
 (e.g. basalt, _______)

                            Other rocks were acted on by   Sometimes have tiny crystals,
      Metamorphic           heat and _______ over a long   no fossils, always hard and
                            time                           sometimes arranged in
   (e.g. ______, slate)                                    _______



    Words to use – layers, stuck, granite, marble, fossils, limestone,
                   crystals, pressure, magma, solid
06/11/12
  Conservation of mass in reactions
            In any reaction the total mass of products is
            the same as the total mass of the reactants

Example 1 – Magnesium oxide and hydrochloric acid
                     H   Cl
     Mg
            O                        Cl                        H
                                          Mg      Cl               O H
                     H   Cl



1 x magnesium, 1 x oxygen, 2 x      Also 1 x magnesium, 1 x oxygen, 2
hydrogen and 2 x chlorine atoms    x hydrogen and 2 x chlorine atoms

Example 2 – Burning methane
        H       H        O                                 O
                              O               O        H       H
            C                             C
       H                 O
                H             O      O                 H   O
                                                               H
Calcium Carbonate
                                                         06/11/12


Calcium carbonate is a common chemical in the Earth and we’ve
already come across it in a number of forms:




      Limestone
                                               Chalk




                                   Marble (made from
                                   chalk or limestone)
Limestone
                                         06/11/12




View video of limestone being quarried
Limestone
                                                       06/11/12


Limestone is a __________ rock made up of
mainly calcium carbonate. It’s cheap and easy to
obtain. Some uses:
1) Building materials – limestone can be quarried
and cut into blocks to be used in _______.
However, it is badly affected by ____ ____.
2) Glass making – glass is made by mixing limestone
with _____ and soda:

       Limestone + sand + soda            glass
3) Cement making – limestone can be “roasted” in a rotary kiln
to produce dry cement. It’s then mixed with sand and gravel
to make _______.
   Words – sand, building, sedimentary, concrete, acid rain
06/11/12
Pros and Cons of quarrying limestone

Reasons why quarrying limestone   Reasons why quarrying limestone
         is a good idea                    is a bad idea
Limestone
                                                               06/11/12


Limestone has a number of uses when it undergoes chemical
reactions. There are two reactions to know:

1) Firstly, a THERMAL _________________ reaction is used
to break the calcium carbonate down into calcium ______ and
_______ __________:
                            HEAT
     Calcium carbonate             calcium oxide + carbon dioxide

2) _____ is then added to produce calcium __________:

                              WATER
            Calcium oxide              calcium hydroxide



           Words – hydroxide, decomposition, carbon
                    dioxide, water, oxide
The “Limestone Cycle”
                                                        06/11/12




                   Calcium Carbonate
                                  CO2
                   (limestone)
  Step 4:
  add CO2                               Step 1:
                                        heat


Calcium Hydroxide solution              Calcium Oxide



  Step 3: add                            Step 2:
  more water                             add a little
  and filter                             water
                    Calcium Hydroxide
06/11/12
  Uses of these Calcium compounds
Calcium carbonate (limestone), calcium oxide and calcium
hydroxide have a number of uses:

1) Neutralising acidic soil – calcium carbonate,
calcium hydroxide and calcium oxide are _______
and can be used to ________ soil acidity to help
______ growth.

2) Removing pollutants – calcium
carbonate can be used as a “_______”
to remove acidic gases from a coal-
fired power station’s waste products,
helping prevent ____ _____.

    Words – acid rain, alkaline, plant, scrubber, neutralise
06/11/12
  Thermal decomposition of carbonates
Limestone undergoes thermal decomposition when heated.
The same happens to other carbonates. For example, consider
copper carbonate:




                      Copper carbonate
                      (green) turns into
                      copper oxide (black)
                                                     Limewater
                      Limewater goes
                      cloudy due to carbon
                      dioxide being made

              Copper carbonate   copper oxide + carbon dioxide
Topic 3 – Acids
                                                      06/11/12




               Indigestion
Learning Objective: Be able to explain why stomach
acid is produced and how antacids are used to
neutralise the excess acid that causes indigestion.



Starter: Write down as many facts you know about
acids, alkalis and neutralisation.
Learning Outcomes
Neutralisation reactions                            06/11/12



When acids and alkalis react together they will NEUTRALISE
each other:


 Sodium hydroxide                                 Hydrochloric acid

  Na    OH                                           H      Cl

                The sodium replaces the
                hydrogen from HCl



              Na     Cl                   H 2O


             Sodium chloride              Water
Neutralisation experiment
                                                                    06/11/12



In this experiment we mixed sodium hydroxide (an _____) and
hydrochloric acid together and they ________ each other.
The equation for this reaction is…

  Sodium hydroxide + hydrochloric acid          sodium chloride + water

A ____ was formed during the reaction, and we could have
separated this by __________ the solution. The salt that we
formed depended on the acid:

          • Hydrochloric acid will make a CHLORIDE
          • Nitric acid will make a _________
          • Sulphuric acid will make a _________

     Words – nitrate, neutralised, alkali, sulphate, salt, evaporating
Stomach Acid
                                                        06/11/12




Hydrochloric acid is used in the stomach to
help _______ and to kill ______. If we eat
too many “rich” foods our stomachs create
too much ____ – this is called ______. This
acid needs to be neutralised by taking
indigestion tablets. Indigestion tablets
contain substances such as _______ that
neutralise excess stomach acid.




   Words – digestion, indigestion, acid, alkalis, bacteria
Topic 3 – Acids
                                                       06/11/12




            Neutralisation
Learning Objective: Be able to explain how acids are
neutralised


Starter: Complete the following word equations:

Hydrochloric Acid + Sodium Hydroxide
Hydrochloric Acid + Calcium Carbonate
Sulphuric Acid + Aluminium Hydroxide
Learning Outcomes
Neutralisation reactions
                                                                    06/11/12


A neutralisation reaction occurs when an acid reacts with an alkali. An
alkali is a metal oxide or metal hydroxide dissolved in water.

                ACID + ALKALI            SALT + WATER


            O                             Cl                    H
       Na              H   Cl                  Na                   O H
            H



Copy and complete the following reactions:
1) Sodium hydroxide + hydrochloric acid
2) Calcium hydroxide + hydrochloric acid
3) Sodium hydroxide + sulphuric acid
4) Magnesium hydroxide + sulphuric acid
Making salts
                                                         06/11/12



Whenever an acid and alkali neutralise each other we are left
with a salt, like a chloride or a sulphate. Complete the
following table:

                Hydrochloric
                                Sulphuric acid    Nitric acid
                   acid

Sodium         Sodium
hydroxide      chloride +
               water
Potassium                      Potassium
hydroxide                      sulphate +
                               water
Calcium                                          Calcium
hydroxide                                        nitrate +
Using different bases
                                                                      06/11/12


A metal oxide base:
   Acid + metal oxide                  natural salt solution + water

                                       heat
Suphuric acid + copper oxide                     copper sulphate + water
           H2SO4(aq) + CuO(s)        heat       CuSO4(s) + H2O(l)


A metal carbonate base:
 Acid + metal carbonate                natural salt sol n + water + CO2

                                      heat
Sulphuric acid + calcium carbonate              calcium sulphate + water + CO 2

    H2SO4(aq) + CaCO3(s)      heat          CaSO4(aq) + + H20(l) + CO2(g)
06/11/12
  Reactions of metals carbonates with acid
A metal carbonate is a compound containing a metal, carbon
and oxygen.
 METAL CARBONATE + ACID      SALT + CARBON DIOXIDE + WATER

  Mg       O   H                      Cl     O
                   Cl
                                 Mg                      O
       C                                     C       H       H
  O
           O   H            Cl
                   Cl                        O




Copy and complete the following reactions:
1) Magnesium carbonate + hydrochloric acid
2) Calcium carbonate + hydrochloric acid
3) Sodium carbonate + sulphuric acid
06/11/12
Reactions of metal oxides with acid
A metal oxide is a compound containing a metal and oxide. They are
sometimes called BASES. For example:
                                                                     O
                                    O                           Al
           O                            Na                           O
      Mg                       Na
                                                                Al
                                                                     O
 Magnesium oxide              Sodium oxide                  Aluminium oxide
           METAL OXIDE + ACID                     SALT + WATER

                     H   Cl
     Mg
           O                                 Cl                      H
                                                  Mg   Cl                O H
                     H   Cl

Copy and complete the following reactions:
1) Magnesium oxide + hydrochloric acid
2) Calcium oxide + hydrochloric acid
3) Sodium oxide + sulphuric acid
Electrolysis of Hydrochloric Acid           06/11/12




 Positive
electrode
               +          H+
                                     -   Negative
                                         electrode
               +                     -
               +         Cl-         -
Hydrochloric
               +                H+   -
                   Cl-
   acid
                               H+
                   Cl-
Testing for Hydrogen
                       06/11/12




        “POP”
Testing for Chlorine
                                                         06/11/12




Chlorine “bleaches” damp indicator paper. It is also a toxic gas
so don’t breathe it! This leads to problems when it comes to
large-scale manufacture of chlorine gas.
Topic 3 – Acids
                                                   06/11/12




        The Importance of
             Chlorine
Learning Objective: Be able to produce a mind map to
show how chlorine is produced, what chlorine is used
for and the potential problems with chlorine.
importance and the show what the uses

Starter: Complete the true and false statements
about chlorine.
Learning Outcomes
Electrolysis of seawater
                                                                  06/11/12


      Seawater is a mixture of water and salt (sodium chloride)
      and we can electrolyse it to produce chlorine and other
      useful products:


           Chlorine gas (Cl2)           Hydrogen gas (H2)




Sodium
chloride
solution
(seawater)
NaCl(aq)
                                                    Sodium hydroxide
                                                       (NaOH(aq))
                         Positive   Negative
                        electrode   electrode
Uses of chlorine
                                                          06/11/12


Polyvinylchloride (PVC) is made up of lots of monomers of vinyl
chloride (chloroethene):
   H            Cl     H           Cl      H    H     H   H

       C    C              C   C           C   C      C   C
  H             H     H            H       H    H     H   H
 Chloroethene          Lots more        Polyvinylchloride (PVC)
   monomer            Chloroethene
                       monomers

Chlorine is also used in the manufacture of bleach.
Sodium hydroxide is reacted with chlorine to form
sodium hypochlorite (bleach):
           Cl2 + 2 NaOH → NaCl + NaClO + H2O
Topic 3 – Acids
                                                      06/11/12




        Electrolysis of Water
Learning Objective: Be able to explain what are the
products from the electrolysis of water and how to
test for these gases.


Starter: How would you test for Hydrogen, Chlorine,
Carbon Dioxide and oxygen gas?? Write it down
Learning Outcomes
Electrolysis of Water
                                                                06/11/12


Water is two atoms of hydrogen and one atom of
oxygen. It can be electrolysed to break it down:     H    O
                                                                H


             Oxygen gas (O2)                Hydrogen gas (H2)




    Water
    H 2O




                         Positive      Negative
                        electrode      electrode
Testing for Oxygen
                                       06/11/12




Oxygen will relight a glowing splint
06/11/12
Topic 4 – Obtaining and Using Metals

                       Ores
Learning Objective: Be able to explain how metals are
extracted using the reactivity series

Starter: What is the reactivity series??
Learning Outcomes
Reactivity series demonstration


 •   All metal elements have a different reactivity.
 •   Some such as sodium are very reactive even in air.
 •   Others such as gold are extremely unreactive.
 •   Watch the demonstration and think about which
     elements are more reactive.
Finding an order?


• Can you place these elements a list of reactivity
  with most reactive a the top and least at the
  bottom?
                      Sodium
                      Sodium
  Copper
  Copper                                  Zinc
                                          Zinc

                     Magnesiu
                     Magnesiu
                        m
                        m
      Gold
      Gold                                  Iron
                                            Iron
Extracting Metals
                                                     06/11/12



Some definitions:

A METAL ORE is a mineral or mixture of
minerals from which it is “economically
viable” to extract some metal.

Most ores contain METAL OXIDES (e.g. rust = iron oxide).


To “extract” a metal from a metal oxide we need to REDUCE
the oxygen. This is called a REDUCTION reaction. To put it
simply:

         Iron                      “Reduce” the oxygen
                    Iron   Oxide
         ore                       to make iron
How do we do it?                         06/11/12


Potassium     Metals ABOVE CARBON, because
 Sodium       of their high reactivity, are
              extracted by ELECTROLYSIS,
 Calcium
              which is very expensive!
Magnesium
               Metals BELOW CARBON are
Aluminium      extracted by heating them with
 Carbon        carbon in a BLAST FURNACE.
               This is a “displacement reaction”
  Zinc
  Iron
   Tin      Carbon             Iron Oxide
  Lead
 Copper
            These LOW REACTIVITY metals won’t
  Silver    need to be extracted because they are
  Gold      SO unreactive you’ll find them on their
            own, not in a metal oxide
 Platinum
Extracting metals


• A metal can be extracted from a compound by
  reacting with an element higher up in the
  reactivity series.
• So for example copper is more reactive than
  silver.
• If we add copper metal to silver nitrate compound
  we make silver metal.
• Draw a picture of this in your book.
Extracting iron


• Iron ore (haematite) is iron oxide.
• To make iron we need to remove the oxygen.
• This process is called REDUCTION


Copy down this equation

Iron oxide + carbon  Iron + Carbon
Iron oxide + carbon  Iron + Carbon
                            dioxide
                            dioxide
Extracting Iron from its ore


• Carbon can also be put into the reactivity series
  and is higher (more reactive) than iron.
• This means iron can be extracted from its ore
  using carbon.
Notes to copy and complete


Metals that are ______ reactive than carbon in the
 reactivity series can be ___________ from their
 oxides by _________ with ________.

Iron oxide is reduced in the _________ ________
  to make iron.

[extracted, reduction, carbon, less, blast furnace]
What are Ores?
Most metals are too …………… to exist on their own in the ground.
Instead they exist combined with other elements (typically o………..
or sulphur) as ……………….. called ………….
A few metals are so ……………….. that they exist uncombined, as
……….metals e.g. gold, ………………..


 Metal          Name of ore      Compound in ore
   Words:
 Aluminium      Bauxite          Aluminium oxide (Al2O3)
   ores           silver          reactive
   oxygen          compounds      unreactive        pure
Displacement Reactions

1. Iron + Copper Sulphate  Iron Sulphate + Copper

2. Copper + Silver Nitrate  Copper Nitrate + Silver

3. Sodium + Zinc Carbonate  Sodium Carbonate + Zinc

4. Potassium + Iron Oxide  Potassium Oxide + Iron

5. Gold + Copper Carbonate  Gold + Copper Carbonate

        No reaction! Can you figure out why?
How do we extract metals from ores?


Watch this video clip:
http://jchemed.chem.wisc.edu/JCESoft/CCA/samples/cca7therm
It is called the thermite reaction.
The symbol equation is: Fe2O3 + Al  Al2O3 + Fe


1. Copy out the symbol equation and write the word equation
   underneath.
2. Why does this reaction happen?
3. Do you think that it’s a commercially viable way of extracting
   iron from its ore? Explain your answer.
So how is it done?


Potassium
Sodium
Magnesium
                      The reactivity series of metals…
Aluminium
Zinc
         Carbon can be used to extract some metals from
Iron
         their ores e.g.
Copper
         Copper oxide + Carbon  Copper + Carbon dioxide
Silver
         The copper oxide has lost oxygen. This is called a
Gold     reduction reaction.
Potassium
            Extracted from their ores by
Sodium      electrolysis (using electricity)
Aluminium
Carbon
Zinc
            Extracted from their ores by
Iron        reduction by carbon
Copper
Silver      No extraction necessary – found
Gold        pure in the ground.
Extracting metals
                                                                 06/11/12



1) What is an ore?
2) In what form are metals usually found in the Earth?
3) How do you get a metal out of a metal oxide?
4) What is this type of reaction called?

       Type of metal             Extraction process   Examples



 High reactivity (i.e anything
        above carbon)

    Middle reactivity (i.e.
   anything below carbon)

        Low reactivity
06/11/12
           Extracting Aluminium




Aluminium has to be extracted from its ore by electrolysis. This is
because aluminium is very ___________ and so it cannot be extracted
using ______. The amount of energy and _____ required to extract
aluminium and other metals is very high and so ________ is a much
better option.


             Words – reactive, recycling, money, carbon
Copper, Aluminium and Titanium
                                                                 06/11/12




   Metal         Uses and why           Extraction          Problems
                                         method


   Copper       Electrical wires –     Electrolysis       Limited supply
                 good conductor


    Gold          Jewellery –         None needed –       Limited supply
                 attractive and      its unreactive so       and very
                  resistant to       you find it in the     expensive
                   corrosion           Earth as gold
Aluminium and   Planes – light and   Complicated and      Expensive and
   titanium         corrosion          expensive           difficult to
                    resistant                                extract
06/11/12
Topic 4 – Obtaining and Using Metals

         Oxidation and Reduction
Learning Objective: Be able to explain the terms
oxidation and reduction and relate it to equations


Starter: If reduction means removing
the oxygen what do you think oxidation
means??
06/11/12
Learning Outcomes
Rusting
                                                    06/11/12




Rust is a hydrated form of
iron oxide. It is formed
when iron and/or steel
combines with oxygen and
water in an oxidation
reaction:

     Iron + oxygen + water   hydrated iron (III) oxide
Rusting
                                                    06/11/12


Task: To investigate what causes rusting




   Tube 1 –       Tube 2 –       Tube 3 –      Tube 4 –
    drying         boiled       water + air   water + air
    agent          water                        + salt
Rusting
                                                     06/11/12


Task: To investigate what causes rusting




    No rust        No rust          Rust      Lots of rust

      Iron + oxygen + water        hydrated iron oxide
Reducation and Oxidation
                                                               06/11/12


Some examples of reduction:
                                 heat
    Aluminium + iron oxide                aluminium oxide + iron
           2Al(s) + Fe2O3(s)     heat     Al2O3(s) + 2Fe(s)


                                 heat
     Lead oxide + carbon                  lead + carbon dioxide
             2PbO(s) + C(s)      heat     2Pb(s) + CO2(s)

An example of oxidation:
                                   heat
      Magnesium + oxygen                     magnesium oxide
                 Mg(s) + O2(s)     heat     2MgO(s)
More on Redox Reactions
                                                         06/11/12


Basically, during a redox reaction electrons are either lost or
gained:

                   The Golden Rule: OILRIG
                Oxidation Is Loss (of electrons)
                Reduction Is Gain (of electrons)

For example:
Fe     Fe2+      These reactions both involve the loss of
2Cl-    Cl2      electrons – they are Oxidation reactions


Fe2+    Fe       These reactions both involve the gain of
                 electrons – they are Reduction reactions
Cl2    2Cl-
C1.18 Reactions
                                            .




Is the substance in red being oxidised or
reduced in the following reaction?

magnesium + oxygen → magnesium oxide

Oxidised
C1.18 Reactions
                                              .




Is the substance in red being oxidised or
reduced in the following reaction?

lead oxide + carbon → lead + carbon dioxide

Reduced
C1.18 Reactions


Is the substance in red being oxidised or
reduced in the following reaction?

magnesium + hydrogen → magnesium + water
  oxide

Reduced
C1.18 Reactions


Is the substance in red being oxidised or
reduced in the following reaction?

nickel + oxygen → nickel oxide

Oxidised
C1.18 Reactions


Is the substance in red being oxidised or
reduced in the following reaction?

4 Na + O2 → 2 Na2O


Oxidised
C1.18 Reactions


Is the substance in red being oxidised or
reduced in the following reaction?


Cr2O3 + 2 Al → 2 Cr + Al2O3


Reduced
06/11/12
Topic 4 – Obtaining and Using Metals

             Recycling Metals
Learning Objective: Be able to explain the importance
of recycling


Starter: Explain how recycled is carried out in
Newham
Learning Outcomes
Recycling
                                                      06/11/12



  Why recycle metals?

1) Less space will be needed for landfill sites
2) Recycled metals only need about 1/10th of the energy to
   produce compared to producing new metals
3) Recycling saves on raw materials
4) Less excavation and mining costs
06/11/12
        Topic 4 – Obtaining and using metals

      Properties of metals and Alloys
Learning Objective: Explain why certain metals are
used in relation to their properties.
Describe ways metal properties can be improved.


Starter: Sort out he properties of the metals on the
worksheet.
Learning Outcomes
C1.20 Why use that metal?




     Why are electrical cables made from copper?




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C1.20 Why use that metal?




     Why are aeroplanes made with a lot of aluminium?




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copyright free. This document may have been altered from the original.
C1.20 Why use that metal?




     Why is jewellery made from gold?




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C1.20 Why use that metal?




     Why are cars made from steel?




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C1.20 Why use that metal?




     Why are cooking pans made from aluminium?




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C1.20 Why use that metal?




     Why is gold used on audio cables?




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C1.20 Why use that metal?




     Why are hot water pipes made from copper?




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C1.20 Why use that metal?




     Why are bridges made from steel?




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C1.20 Why use that metal?




     Why is aluminium used in heat sinks for
     microprocessors?




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06/11/12
Using impurities to strengthen Iron
In pure iron all
impurities are
removed. This
makes the iron soft:




Adding 1% impurities
makes the iron much
stronger:
Alloys
                                                          06/11/12


Steel is an “alloy” – i.e. a mixture of metals. Here are other
alloys:




Gold mixed with       Aluminium mixed          Aluminiun mixed
copper                with magnesium           with chromium
                      and copper
06/11/12
                    Making steel
     Strong                                     Strength


                                                Hardness

                                                 Amount of
      Weak                                       carbon
                    0.5%        1%       1.5%    added (%)




Steel with a low    Steel with a high    Steel with chromium
carbon content is   carbon content is    and nickel is called
easily shaped       strong but brittle   stainless steel
Smart Alloys
                                                         06/11/12


A “smart alloy” is one that can “remember” its original state
after being bent or stretched.




These glasses are made from a “smart” material – if they are
bent they will return to their original shape. They could be
made from an alloy called “nitinol” (an alloy of nickel and
titanium) which can be bent but then returned to its original
shape simply by heating to its “transformation temperature”.
Gold alloys
                                                               06/11/12


Gold can be mixed with other metals to make alloys with
different properties. For example:
         24-Carat gold                        9-Carat gold




“Pure gold” – 99.99% of the atoms      “9 carat gold” – around 9/24ths
in this bar are gold atoms (fineness   of the atoms in these earrings
off 999.9). Pure and malleable but     are gold atoms. Harder than
soft.                                  pure gold but less malleable.
Materials in a Car
                                                  06/11/12



    Copper wires        Glass           Nylon
                     windscreen       seatbelts




Plastic trim
                                    Steel body

                     Alloy wheels
Iron or aluminium?
                                                             06/11/12



Aluminium:

Does not corrode
Less dense so it’s lighter

Iron:

Cheaper than aluminium
Magnetic so easily recycled


        Most cars are made from steel (an alloy of carbon)

From 2015 95% of a car will have to be made from recycled
material. What are the advantages of this?
06/11/12
              Topic 5 – Fuels

                   Crude Oil
Learning Objective: Explain how crude oil is formed
and its uses.

Starter: What elements are contained in
Hydrocarbons
Learning Outcomes
Fuels
                                                          06/11/12



Fuels are substances that can be used to release useful
amounts of energy when they burn, e.g.




    Wood             Oil           Gas               Coal


                    These fuels are called “fossil fuels” and
                    are described as being “non-renewable”.
Crude Oil
            06/11/12
06/11/12
              Topic 5 – Fuels
             Crude Oil fractions
                Learning Objective:
Explain how hydrocarbon fractions are separated.


Starter: Write down three facts you remember form
last lesson
Learning Outcomes
06/11/12
    Hydrocarbons and crude oil
             Crude oil is a mixture of HYDROCARBONS
             (compounds made up of carbon and hydrogen).
             Some examples:

         H    H
                                                      Longer chains mean…




                                 Increasing length
    H    C    C   H
         H    H
                                                     1. Less ability to flow
        Ethane
                                                     2. Less flammable
    H    H    H       H
H   C    C    C       C   H                          3. Less volatile
    H    H    H       H
                                                     4. Higher boiling point
        Butane
Distillation revision
                                                           06/11/12




                                   This apparatus can be used to
                                   separate water and ink
                                   because they have different
                                   _____ ______. The ______
                                   will evaporate first, turn back
                                   into a _______ in the
                                   condenser and collect in the
                                   _______. The ink remains in
                                   the round flask, as long as the
                                   _______ does not exceed
                                   ink’s boiling point. This
                                   method can be used to
                                   separate crude oil.



Words – temperature, boiling points, water, beaker, liquid
.
                                                            06/11/12
Sort them into benefits and drawbacks of using oil
1 Accidents with oil wells or oil tankers can pollute the sea and
kill wildlife.
2 Cars that run on petrol are much more convenient than
battery-powered cars.
3 Burning fossil fuels produces carbon dioxide and other
polluting gases.
4 We can make lots of different chemicals out of the
substances in crude oil.

5   Crude oil will run out one day.

6   Bitumen is very useful for making roads.

7   We need oil to lubricate engines and other moving machines.

8 Petrol can cause explosions if it is not transported and stored
  correctly.
Fractional distillation
                                                                     06/11/12

Crude oil can be separated by fractional distillation. The oil is evaporated
and the hydrocarbon chains of different lengths condense at different
temperatures:


Fractions with
low boiling
points condense
at the top




Fractions with
high boiling
points condense
at the bottom
9Hb              How fractional distillation works
                                 C1.23 Fractional distillation




                   How fractional
                  distillation works


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9Hb              How fractional distillation works
                                 C1.23 Fractional distillation



      Crude oil is a mixture of different hydrocarbon molecules.
      The molecules have different numbers of carbon and
      hydrogen atoms in them.



     Some of the different
     molecules in crude oil.




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9Hb              How fractional distillation works
                                 C1.23 Fractional distillation



       Molecules of different sizes
       have to be separated
       before oil can be used. This
       is done in an oil refinery.
       The process of separating
       crude oil is called
       fractional distillation. The
       different mixtures produced
                                                            An oil refinery. The tall towers are
       are called fractions.                                'fractionating columns'.




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9Hb              How fractional distillation works
                                 C1.23 Fractional distillation



       Fractional distillation works because the different molecules in
       crude oil have different boiling points.
       There are tiny forces of attraction between all molecules. The
       longer the molecule, the bigger this force. So long molecules
       tend to stick together more than small ones.
       The bigger the force, the more energy is needed to allow the
       molecules to break away from the liquid and form a gas. So
       longer molecules have higher boiling points.




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9Hb              How fractional distillation works
                                 C1.23 Fractional distillation


                                                  gases          The diagram shows a
                                                                 fractionating column.
                                                                 It is hotter at the
                                                  petrol         bottom than at the
             column                                              top.
             getting
              cooler                              kerosene



                                                  diesel oil     Click on a number to
                                                                 find out more.
                                                  fuel oil




                                                  bitumen




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9Hb              How fractional distillation works
                                 C1.23 Fractional distillation


                                                  gases
                                                                  1
                                                                  Crude oil is heated
                                                  petrol
                                                                  until it boils. The gas
             column
                                                                  is fed into the bottom
             getting
              cooler
                                                                  of the fractionating
                                                  kerosene
                                                                  column.
                                                  diesel oil




                                                  fuel oil




                                                  bitumen

                                                                       Back to fractionating column

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9Hb              How fractional distillation works
                                 C1.23 Fractional distillation


                                                  gases
                                                                  2
                                                                  The hot crude oil vapour goes
                                                  petrol
                                                                  into the fractionating column.
             column
             getting
                                                                  It starts to cool down. Fuel oil,
              cooler                              kerosene        waxes and bitumen condense
                                                                  and run out of the pipe at the
                                                  diesel oil      bottom.
                                                                  These fractions have the
                                                  fuel oil
                                                                  longest molecules and the
                                                                  highest boiling points.
                                                  bitumen

                                                                       Back to fractionating column

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9Hb              How fractional distillation works
                                 C1.23 Fractional distillation


                                                  gases
                                                                  3
                                                                  The rest of the crude oil
                                                  petrol
                                                                  gas rises up the column.
             column
                                                                  It cools as it rises.
             getting
              cooler                              kerosene        The largest molecules left
                                                                  in the gas condense next.
                                                  diesel oil      They fall onto the 'tray'.

                                                  fuel oil




                                                  bitumen

                                                                       Back to fractionating column

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9Hb              How fractional distillation works
                                 C1.23 Fractional distillation


                                                  gases
                                                                  4
                                                                  The next longest molecules
                                                  petrol
                                                                  condense here.
             column                                               Each set of trays collects
             getting
              cooler                              kerosene        condensed molecules with
                                                                  carbon numbers in a
                                                  diesel oil      particular range.

                                                  fuel oil




                                                  bitumen

                                                                       Back to fractionating column

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9Hb              How fractional distillation works
                                 C1.23 Fractional distillation


                                                  gases
                                                                   5
                                                                   The condensed liquids
                                                  petrol
                                                                   are removed through
                                                                   pipes. Some of them go
             column
             getting                                               to further fractionating
              cooler                              kerosene
                                                                   columns to separate
                                                                   them further.
                                                  diesel oil




                                                  fuel oil




                                                  bitumen

                                                                       Back to fractionating column

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9Hb              How fractional distillation works
                                 C1.23 Fractional distillation


                                                  gases
                                                                   6
                                                                   The smallest molecules
                                                  petrol
                                                                   in crude oil are gases at
                                                                   normal temperatures.
             column
             getting
              cooler                              kerosene         These gases are
                                                                   removed from the top of
                                                  diesel oil       the column.

                                                  fuel oil




                                                  bitumen

                                                                       Back to fractionating column

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06/11/12
            Match up the names and uses
Fractions

        Gases                   Fuel oil
       Kerosene                  Petrol
       Bitumen                 Diesel oil
Uses
  Fuel for some cars          Fuel for some cars
       Making roads            Cooking in homes
  Fuel for large ships         Fuel for aircraft
       Heating homes         Fuel for some trains
                             Fuel for some power
Making roofs waterproof
                                   stations
06/11/12
06/11/12
              Topic 5 – Fuels
                  Combustion
                  Learning Objective:
•Able to explain what is produced when hydrocarbons
burn.

Starter: Draw a brainstorm to show everything you
remember about crude oil.
Learning Outcomes
Burning Hydrocarbons
                                                              06/11/12


Burning hydrocarbons will produce water, carbon dioxide and
energy:

      H       H       O                               O
                          O               O       H       H
          C                           C
      H               O
              H           O       O               H   O
                                                          H
     Methane      +   Oxygen      Carbon      +   Water
                                  dioxide

In this reaction the hydrocarbon is oxidised.
Testing for Carbon Dioxide
                                  06/11/12




          Gas




                Limewater


                Limewater turns
                milky/cloudy
Burning Hydrocarbons
                                                                            06/11/12

               H              H       O                                 O
                                                           O       H
Lots of               C
                                           O
                                                   C
                                                                              H
oxygen:       H                       O
                              H            O   O                   H    O
                                                                              H
              Methane             +   Oxygen   Carbon          +   Water
                                               dioxide
                                                                   H    O
          H               H           O                                       H
                                           O               O
                  C                                                     O
          H                                        C               H          H
Some                  H               O
                                           O
oxygen:        H              H                    C
                                                           O       H    O
                                                                              H
                      C               O
                                           O                            O
              H                                                    H          H
                              H
              Methane             +   Oxygen    Carbon         +       Water
                                               monoxide
                                                                   H     O
              H               H                                                H
Little                C                O               C
                                           O                             O
oxygen:       H
                          H
                                                                   H           H

          Methane                 +   Oxygen   Carbon          +   Water
C1.24 Balancing equations



           We can represent what happens in chemical reactions
           using symbol equations.
           We use a symbol (of one or two letters) to represent
           atoms of different elements.
           We also use symbols to show how many atoms of
           different kinds are joined together to make a compound.




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C1.24 Balancing equations



          For example:
          Hydrogen chloride molecules are made from one atom of
          hydrogen joined to one atom of chlorine.
                          HCl
                                                   H       Cl

          Water molecules are made from one atom of oxygen joined to
          two atoms of hydrogen. The little '2' shows there are two
          hydrogen atoms.
                          H2O                     H        O

                                                               H

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C1.24 Balancing equations



           Hydrogen gas reacts with chlorine gas to form hydrogen
           chloride.
           Hydrogen and chlorine gases both exist as pairs of atoms.


                   H                         Cl
                        H
                                +                                                  H        Cl
                                                       Cl

                   H2(g)         +                Cl2(g)                                HCl(g)




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C1.24 Balancing equations


           But this isn't quite right yet – the reactants have two atoms of
           hydrogen and two of chlorine. Atoms are not created or
           destroyed in a reaction, so we must have two hydrogen atoms
           and two chlorine atoms in the products.

                                                                                 H        Cl
                   H                         Cl
                        H
                                +
                                                       Cl
                                                                                            H       Cl

                   H2(g)         +            Cl2(g)                                    2HCl(g)




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C1.24 Balancing equations



           The 2 in front of the HCl in the symbol equation shows that
           there are two complete molecules of hydrogen chloride.



                                                                                H        Cl
                   H                         Cl
                       H
                                +
                                                      Cl
                                                                                           H        Cl

                  H2(g)         +            Cl2(g)                                    2HCl(g)




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C1.24 Balancing equations



           Hydrogen and oxygen react to form water.



                                                                                      H       O
                                                     O
                    H            +                                                                H
                         H                    O


                    H2(g)        +             O2(g)                                      H2O(g)




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C1.24 Balancing equations


           There are more oxygen atoms in the reactants than the
           products, so we must have made more than one molecule of
           water.

                                                                              H        O            H       O
                                                O
               H            +                                                              H                    H
                    H                   O


              H2(g)         +            O2(g)                                     2H2O(g)




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C1.24 Balancing equations


           But now there are more hydrogen atoms in the products than
           in the reactants. We must have started with more than one
           hydrogen molecule.
                   H                                                                   O
                                                                              H                     H       O
                        H                       O
               H            +                                                              H                    H
                    H                   O


              2H2(g) +                   O2(g)                                     2H2O(g)




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C1.24 Balancing equations


           This is now a balanced symbol equation to show the
           reaction of hydrogen and oxygen to form water.

                   H                                                                   O
                                                                              H                    H        O
                        H                       O
               H            +                                                              H                    H
                    H                   O


              2H2(g) +                   O2(g)                                     2H2O(g)




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C1.24 Balancing equations


           Try these examples. Click on an example to see how to work
           out the balanced symbol equation.


                                Methane (CH4) reacts with oxygen
                                to form carbon dioxide and water.


                                   Magnesium reacts with oxygen
                                  to form magnesium oxide (MgO).




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C1.24 Balancing equations


           Methane (CH4) reacts with oxygen to form carbon dioxide
           and water.


                                                                              O
                H
                                               O                          C                 H      O
         H      C       H       +                                                  +
                                          O                                                            H
                H                                                     O



             CH4(g)            +         O2(g)                       CO2            +         H2O(g)



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C1.24 Balancing equations



           There are more oxygen atoms in the products than the
           reactants, so we must have started with more oxygen.

                                               O
                                                                              O
                H                         O
                                                                          C                 H      O
         H      C       H       +                                                  +
                                               O                                                       H
                H                                                     O
                                          O


             CH4(g)            +         2O2(g)                      CO2            +         H2O(g)



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C1.24 Balancing equations



           Now there are more oxygen atoms in the reactants than the
           products. The reaction must produce more water molecules.

                                               O
                                                                              O              H      O
                H                         O
                                                                          C                             H
         H      C       H       +                                                  +
                                               O
                H                                                     O                       H      O
                                          O
                                                                                                         H

             CH4(g)            +         2O2(g)                      CO2            +         2H2O(g)



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C1.24 Balancing equations



           The equation is balanced. You can check this by counting up
           the numbers of atoms on each side of the equation.

                                               O
                                                                              O              H      O
                H                         O
                                                                          C                             H
         H      C       H       +                                                  +
                                               O
                H                                                     O                       H      O
                                          O
                                                                                                         H

             CH4(g)            +         2O2(g)                      CO2            +         2H2O(g)



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C1.24 Balancing equations


          Magnesium reacts with oxygen to form magnesium oxide
          (MgO).




               Mg                              O                                Mg
                                +                                                         O
                                          O



             Mg(s)             +         O2(g)                                      MgO(s)




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C1.24 Balancing equations


          There are more oxygen atoms in the reactants than the
          products, so the reaction must produce more magnesium
          oxide.
                                                                                Mg        O

               Mg                              O
                                +
                                          O                                     Mg        O



             Mg(s)             +         O2(g)                                      2MgO(s)




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C1.24 Balancing equations


          And we must have started with more than one magnesium
          atom…

                                                                                Mg        O
                   Mg
                                               O
        Mg                      +
                                          O                                     Mg        O



             2Mg(s)            +         O2(g)                                      2MgO(s)




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C1.24 Balancing equations


          Now the symbol equation is balanced.



                                                                                Mg        O
                   Mg
                                               O
        Mg                      +
                                          O                                     Mg        O



             2Mg(s)            +         O2(g)                                      2MgO(s)




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C1.24 Questions and answers



1 Give an example of a hydrocarbon fuel.


A: Any named hydrocarbon that can be used as a fuel – petrol,
   diesel, kerosene etc.


2 Why is combustion an example of an oxidation reaction?

A: The reaction combines a fuel with oxygen.




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C1.24 Questions and answers




     3 Look at Figure B. What is the source of oxygen that allows
       the candle to burn?


     A: Air




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C1.24 Questions and answers



     4 In Figure B, which part of the apparatus shows that:
         a carbon dioxide is produced


     A: Limewater


          b oxygen is produced?


     A: Copper sulfate



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C1.24 Questions and answers




     5 Butane is a hydrocarbon compound found in crude oil.
       Write a word equation for the combustion of butane.


     A: Butane + oxygen → carbon dioxide + water




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C1.24 Questions and answers




     6 Limewater is calcium hydroxide solution, Ca(OH)2. It forms
          calcium carbonate,CaCO3, and water when it reacts with
          carbon dioxide.
          a Write a word equation for this reaction.


     A: Calcium hydroxide solution + carbon dioxide
                                     → calcium carbonate + water



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C1.24 Questions and answers



          b Why does limewater go milky when carbon dioxide is
          bubbled through it?


     A: The calcium carbonate formed is a solid; the cloudiness is
        due to tiny particles of solid calcium carbonate
        (a precipitate) in the water.


          c Write a balanced equation for the reaction.


     A: Ca(OH)2(aq) + CO2(g) → CaCO3(s) + H2O(l)
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C1.24 Questions and answers




     7 Jose says, ’Burning petrol produces nitrogen oxides and
       water’. Explain how you can tell he is wrong just by using
       the fact that petrol is a mixture of hydrocarbon molecules.


     A: Answers may include: Petrol compounds are hydrocarbons
        so they only contain carbon and hydrogen atoms; burning
        uses only oxygen from the air; neither of the reactants
        contain nitrogen, so a compound contains nitrogen cannot
        be one of the products of the reaction.

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06/11/12
              Topic 5 – Fuels
  Incomplete combustion and Acid Rain

                 Learning Objective:
 Explain what happens if there is not enough oxygen
                    for burning.
       Explain the consequences of Acid Rain

Starter: Write a balanced equation to show
combustion.
Learning Outcomes
Incomplete Combustion
                                                         06/11/12


As well as producing carbon monoxide, incomplete combustion
can also produce soot:

                                                     H   O
           H       H                                         H
Little         C            O            C
                                O                        O
oxygen:    H
                   H
                                                     H       H

          Methane      +   Oxygen      Carbon    +   Water


                                        “Soot”
06/11/12
Why Carbon Monoxide is Dangerous
Basically, carbon monoxide “sticks” to red blood cells instead
of oxygen, causing anybody inhaling it to essentially suffocate:

                 CO    1) Carbon Monoxide is breathed in
                       2) The molecule “sticks” to red blood
                          cells instead of oxygen
                       3) The red blood cells transport the
                          “carboxyhaemoglobin” molecule to
                          the rest of the body and the body’s
                          cells are starved of the oxygen
                          needed for respiration.

                 Carbon monoxide is odourless, colourless and
                 non-irritating so it’s very difficult to detect!
Burning Fossil Fuels
                                                               06/11/12


     Burning fossil fuels like oil and coal causes pollution.
Oil contains carbon:
          H       H      O                                 O
                               O                  O   H        H
              C                               C
         H               O
                  H            O          O           H    O
                                                               H



                               Carbon dioxide is a “greenhouse
                               gas” – it helps cause global warming

Coal contains carbon, sulfur and other particles:
             sulfur + oxygen              sulfur dioxide
     Sulfur dioxide causes acid rain. Other particles can
     cause “global dimming” – sunlight is absorbed by the
     particles in the atmosphere.
06/11/12
C1.26 Questions and answers



1     Why is rain normally slightly acidic?


A: Contains dissolved carbon dioxide from the air.




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C1.26 Questions and answers



     2 A What is ‘acid rain’?


     A: Rain that is more acidic than normal.


          b What causes acid rain?


     A: Acidic gases such as sulfur dioxide and nitrogen oxides
        dissolved in rainwater.


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C1.26 Questions and answers



3 What effect does acid rain have on:
     a the water in rivers and lakes
A: Makes it more acidic (lowers pH).
     b organisms that live in rivers and lakes
A: Can harm or kill them.
     c trees
A: Damages them and can kill them.
     d stone buildings and statues?
A: Weathers the stone by chemical reactions, so it breaks up and
   erodes faster.
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C1.26 Questions and answers




     4 Limestone (calcium carbonate) can be used to neutralise
       the sulfuric acid that makes lakes acidic. Write a word
       equation for this neutralisation reaction.


     A: Calcium carbonate + sulfuric acid
                    → calcium sulfate + water + carbon dioxide




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copyright free. This document may have been altered from the original.
C1.26 Questions and answers



     5 Describe how acid rain forms and describe two ways in
       which acid rain in Europe has been reduced.


     A: Answers may include: Sulfur compounds in burning fossil
        fuels form sulfur dioxide, which dissolves in rain to form an
        acidic solution; sulfur impurities can be removed from fuels
        before they are sold and burnt; for fuels used in power
        stations, an alternative is to remove the sulfur dioxide from
        the waste gases in the chimney, after the fuel is burnt – this
        is done by neutralising the acidic sulfur dioxide gas with
        calcium carbonate.
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copyright free. This document may have been altered from the original.
06/11/12
          Topic 5 – Fuels
            Climate change
             Learning Objective:
Explain how human activity affects the earths
               temperature.
Learning Outcomes
Global Warming
                             06/11/12




           Facts:
           1) The 10 warmest years
              of the last century
              have all occurred
              within the last 15
              years
           2) Sea level has risen by
              between 12 and 24cm
              in the last 100 years
           3) Rainfall has risen by
              1%
The Greenhouse Effect
                                                                 06/11/12

We get heat
                         A lot of this heat is
from the sun:
                         _______ back into space.


                 However, most of it is kept inside the
                 Earth by a layer of gases that prevent
                 the heat escaping by _______ and
                 then re-radiating it back again.
This is called the _________ Effect. It has always been around, but is
    currently being made worse due to:
1) Burning (releasing CO2)
2) __________ (removing trees that remove CO2)
3) Increased micro organism activity (from rotting ______)
4) Cattle and rice fields (they both produce _______)
These changes will cause GLOBAL WARMING and RISING SEA LEVELS
 Words – methane, radiated, absorbing, deforestation, waste, greenhouse
06/11/12
Carbon Dioxide and Global Warming
         Global levels of Carbon Dioxide in PPM




                                                  Is there a
                                                     link?
06/11/12
Reducing the amount of Carbon Dioxide
Scientists are trying to reduce the amount of carbon
dioxide in the atmosphere through a number of
possibilities:

1) “Iron seeding” – this is the process where iron is
intentionally put in seawater to help produce more
phytoplankton which then increases photosynthetic
activity, therefore reducing the amount of CO2 in the
atmosphere.
                                                            Aerial view of
                                                            phytoplankton
                                                            near Argentina

                                   2) Converting CO2 into
                                   hydrocarbons – carbon dioxide can
                                   be converted into hydrocarbons and
                                   then stored in the Earth by putting
                                   it in such places as old oil fields or
                                   coal beds.
Reducing Pollution from vehicles
                                                             06/11/12


A number of suggestions:

1) Buy a new, smaller, cleaner car


2) Buy a “hybrid” car


3) Convert your car to run on biodiesel

4) Make sure your car has a catalytic converter:
            Carbon monoxide + oxygen     carbon dioxide
  Nitrogen monoxide + carbon monoxide   nitrogen + carbon monoxide

5) Use the train or a bus!
06/11/12
              Topic 5 – Fuels
             Biofuels and choosing fuels

                 Learning Objective:
 •Explain the advantages and disadvantages of using
                       biofuels
        •Explain how to choose the best fuel.

Starter: What do you know about biofuels
Learning Outcomes
Ethanol as a biofuel
                                                          06/11/12



Ethanol is an important chemical. Many
countries are increasing the amount of
ethanol put into their petrol supplies:       Ford Escape E85 –
                                              runs on 85% ethanol
Ethanol is a “clean burning” energy source and produces little
or no greenhouse gases. How is it made?

     The “renewable” way            Sugar is produced from
                                      standard crops like
Sugar      ethanol + carbon dioxide  sugar cane and corn

What’s the point?
When ethanol burns it only produces small amounts of carbon
dioxide. Making more cars run on ethanol means having less
cars that need petrol.
C1.28 Photosynthesis and biofuels



A fuel is carbon neutral when the amount of carbon dioxide
absorbed in making the fuel equals the amount of carbon dioxide
produced when it is burned.

Are biofuels carbon neutral?




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     material is not copyright free. This document may have been altered from the original.
C1.28 Photosynthesis and biofuels



Plants use carbon dioxide from the air in photosynthesis. The
material in a plant stores carbon atoms that have been taken out
of the atmosphere.

                                   carbon dioxide




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     material is not copyright free. This document may have been altered from the original.
C1.28 Photosynthesis and biofuels



Plants can be harvested to be turned into fuel.




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     material is not copyright free. This document may have been altered from the original.
C1.28 Photosynthesis and biofuels



Plants must be converted to biofuels such as biodiesel before
they can be used as fuel for vehicles. This is done in a refinery.




     © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This
     material is not copyright free. This document may have been altered from the original.
C1.28 Photosynthesis and biofuels



The biofuel contains carbon that was originally taken out of the
atmosphere by the plants used to make the fuel.




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     material is not copyright free. This document may have been altered from the original.
C1.28 Photosynthesis and biofuels



When the biofuel is burned in engines, carbon dioxide is put into
the atmosphere.




     carbon
     dioxide


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     material is not copyright free. This document may have been altered from the original.
C1.28 Photosynthesis and biofuels



But this carbon dioxide has only recently been taken out of the
atmosphere by the plants used to make the fuel. Overall, no
carbon dioxide has been added to the atmosphere.
Or has it?




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     material is not copyright free. This document may have been altered from the original.
C1.28 Photosynthesis and biofuels



The machinery used to plant the crops and harvest them
needed fuel.
Fuel was needed to make fertilisers to help the crops to grow.
The refinery used energy to convert the plants to biofuel.

Unless all these
processes also
used biofuels, then
the biofuel is not
really 'carbon
neutral'.

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     material is not copyright free. This document may have been altered from the original.
Choosing a biofuel
                                                     06/11/12




Does it create                      How much energy
  pollution?                        does it release?




                        Biofuels            Is it toxic?

How much does
 it cost? How
  much land is                     Does it take more CO2
    needed?
                                   to tranport it than it
                                     takes in from the
    How easy is it to                atmosphere while
      grow/make?                          growing?
Choosing a fuel
                                                      06/11/12




How easily does                        How much energy
   it burn?                            does it release?



                   Which fuel should
                                              Is it toxic?
                       you use?


How much smoke
does it produce?                  Is it easy to use,
                                store and transport?
Hydrogen Fuel Cells
                                                       06/11/12


Basically, a hydrogen fuel cell combines hydrogen and oxygen
to form water and release energy:
Hydrogen Fuel Cells
                                                   06/11/12



Advantages of fuel cells           Advantages of petrol




                    Hydrogen fuel cells
                        vs Petrol
Energy from fuels
                                  06/11/12




  Copper
calorimeter            Water




                        Spirit burner
  Fuel
C1.29 Fuel quiz




           The answers to all these questions are one or more of:

                         • hydrogen
                         • methane
                         • liquid fuels (such as petrol, kerosene
                           and diesel)
                         • solid fuels (such as coal and wood)




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copyright free. This document may have been altered from the original.
C1.29 Fuel quiz




          Which fuel or fuels can be sent through pipes?




© Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not   Answer
copyright free. This document may have been altered from the original.
C1.29 Fuel quiz




          Which fuel or fuels can be sent through pipes?

                         • hydrogen
                         • methane
                         • liquid fuels (petrol, kerosene, diesel)




© Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not
copyright free. This document may have been altered from the original.
C1.29 Fuel quiz




         Which fuel or fuels are used in cars?




© Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not   Answer
copyright free. This document may have been altered from the original.
C1.29 Fuel quiz




         Which fuel or fuels are used in cars?

                        • hydrogen
                        • liquid fuels (petrol, diesel)




© Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not
copyright free. This document may have been altered from the original.
C1.29 Fuel quiz




          Which fuel or fuels are fossil fuels?




© Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not   Answer
copyright free. This document may have been altered from the original.
C1.29 Fuel quiz




          Which fuel or fuels are fossil fuels?

                         • methane
                         • liquid fuels (petrol, kerosene, diesel)
                         • solid fuels (coal)




© Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not
copyright free. This document may have been altered from the original.
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world
Unit c1   chemistry in our world

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Unit c1 chemistry in our world

  • 1. 06/11/12 Chemistry Unit C1 – Chemistry in our World EdExcel
  • 2. 06/11/12 Elements If a solid, liquid or gas is made up of only one type of atom we say it is an element. For example, consider a tripod made up of iron: These atoms are ALL iron – there’s nothing else in here
  • 3. 06/11/12 Compounds Compounds are different to elements. They contain different atoms. Here are some examples: Methane Sodium chloride (salt) Glucose
  • 4. 06/11/12 Some simple compounds… Carbon Methane, CH4 Water, H2O dioxide, CO2 Key Hydrogen Oxygen Ethyne, C2H2 Sulphuric Carbon acid, H2SO4 Sulphur
  • 5. Balancing equations 06/11/12 Consider the following reaction: Sodium + water sodium hydroxide + hydrogen Na Na + O + H H H H H O This equation doesn’t balance – there are 2 hydrogen atoms on the left hand side (the “reactants” and 3 on the right hand side (the “products”)
  • 6. Balancing equations 06/11/12 We need to balance the equation: Sodium + water sodium hydroxide + hydrogen Na O H Na H H O + + O Na H H H H H Na O Now the equation is balanced, and we can write it as: 2Na(s) + 2H2O(l) 2NaOH(aq) + H2(g)
  • 7. Some examples 06/11/12 2 Mg + O2 2 MgO Zn + 2 HCl ZnCl2 + H2 2 Fe + 3 Cl2 2 FeCl3 NaOH + HCl NaCl + H 2O CH4 + 2 O2 CO2 + 2H2O Ca + 2 H2O Ca(OH)2 + H2 2 2 NaOH + H2SO4 Na2SO4 + H 2O 2 3 2 4 CH3OH + O2 CO2 + H 2O
  • 8. Hazard signs to learn… 06/11/12 Acid Corrosive Toxic h i Harmful Irritant Oxidising
  • 9. 06/11/12 Topic 1 – The Earth’s Sea and Atmosphere
  • 10. 06/11/12 The Earth’s Atmosphere For the last 200 million years the atmosphere has remained roughly the same – it contains 78% nitrogen, 21% oxygen, 1% noble gases and about 0.03% CO2 Carbon dioxide, water vapour Oxygen Nitrogen Noble gases
  • 11. 06/11/12 Evolution of the Earth’s Atmosphere Carbon Methane Ammonia Oxygen Nitrogen Others dioxide Present day atmosphere contains 78% nitrogen, 21% oxygen, 1% noble gases and about 0.03% CO2 4 Billion years 3 Billion years 2 Billion years 1 Billion years Present day
  • 12. 06/11/12 Evolution of the Earth’s Atmosphere Volcanic activity Some of the oxygen is releases CO2, methane, converted into ozone. ammonia and water The ozone layer blocks vapour into the out harmful ultra-violet atmosphere. The water rays which allows for the vapour condenses to development of new life. form oceans. 4 Billion years 3 Billion years 2 Billion years 1 Billion years Present day Green plants evolve which take in CO2 and give out oxygen by photosynthesis, increasing the amount of oxygen in the atmosphere. Carbon from CO2 becomes locked up in sedimentary rocks as carbonates and fossil fuels and is dissolved into the sea. Methane and ammonia react with the oxygen and nitrogen is released.
  • 13. 06/11/12 Carbon dioxide in the atmosphere The amount of CO2 in the atmosphere is affected by 3 things: 1) Geological activity moves carbonate rocks deep into the Earth and they release ______ _______ into the atmosphere during volcanic activity. 2) Human activity - When fossil fuels are burned the carbon contained in them reacts with _____ to form CO2. Furthermore, deforestation means that less _____ are around to take in CO2. 3) Increased CO2 in the atmosphere causes a reaction between it and _______. These reactions do not remove ALL of the new CO2 so the greenhouse effect is still getting _______! Words – oxygen, seawater, carbon dioxide, worse, trees
  • 14. 06/11/12 Topic 2 – Materials from the Earth
  • 15. What are rocks? 06/11/12 Rocks are made from a combination of minerals and can be hard or soft depending on how the minerals are arranged. Rocks can be found here… …and here… …and here… …and here
  • 16. Sedimentary rocks 06/11/12 Sandstone Limestone Chalk Conglomerate
  • 17. Sedimentary rocks 06/11/12 How sedimentary rocks are formed: 1) Weathering 2) Transportation 3) Deposition 4) Burial
  • 18. Metamorphic rocks 06/11/12 Quartzite Slate Marble (made from chalk or limestone)
  • 19. Metamorphic rocks 06/11/12 Metamorphic rocks are formed by the combined effect of heat and pressure on other rocks: Pressure from rocks above… …and heat from magma nearby
  • 20. Igneous rocks 06/11/12 Obsidian Granite Pumice
  • 21. Igneous Rock 06/11/12 Granite – a slow cooling rock with big crystals and rich in silica Rhyolite – a fast cooling rock with small crystals and rich in silica Gabbro – a slow cooling rock with Basalt – a fast cooling rock with big crystals and rich in iron small crystals and rich in iron
  • 22. Igneous rocks 06/11/12 Igneous rocks are formed when lava or magma cools down and solidifies If the lava or magma cools QUICKLY it has SMALL crystals If the lava or magma cools SLOWLY it has BIG crystals
  • 23. Summary 06/11/12 Sedimentary, igneous or How they were formed Appearance metamorphic? Sedimentary Small pieces of sediment Usually soft, can contain were ______ together by ________, easily eroded salt and pressure from rocks (e.g. sandstone, _______, above chalk) Liquid rock (______ or lava) Contain ______, very hard, Igneous cooled down and turned back never contain fossils into a ______ (e.g. basalt, _______) Other rocks were acted on by Sometimes have tiny crystals, Metamorphic heat and _______ over a long no fossils, always hard and time sometimes arranged in (e.g. ______, slate) _______ Words to use – layers, stuck, granite, marble, fossils, limestone, crystals, pressure, magma, solid
  • 24. 06/11/12 Conservation of mass in reactions In any reaction the total mass of products is the same as the total mass of the reactants Example 1 – Magnesium oxide and hydrochloric acid H Cl Mg O Cl H Mg Cl O H H Cl 1 x magnesium, 1 x oxygen, 2 x Also 1 x magnesium, 1 x oxygen, 2 hydrogen and 2 x chlorine atoms x hydrogen and 2 x chlorine atoms Example 2 – Burning methane H H O O O O H H C C H O H O O H O H
  • 25. Calcium Carbonate 06/11/12 Calcium carbonate is a common chemical in the Earth and we’ve already come across it in a number of forms: Limestone Chalk Marble (made from chalk or limestone)
  • 26. Limestone 06/11/12 View video of limestone being quarried
  • 27. Limestone 06/11/12 Limestone is a __________ rock made up of mainly calcium carbonate. It’s cheap and easy to obtain. Some uses: 1) Building materials – limestone can be quarried and cut into blocks to be used in _______. However, it is badly affected by ____ ____. 2) Glass making – glass is made by mixing limestone with _____ and soda: Limestone + sand + soda glass 3) Cement making – limestone can be “roasted” in a rotary kiln to produce dry cement. It’s then mixed with sand and gravel to make _______. Words – sand, building, sedimentary, concrete, acid rain
  • 28. 06/11/12 Pros and Cons of quarrying limestone Reasons why quarrying limestone Reasons why quarrying limestone is a good idea is a bad idea
  • 29. Limestone 06/11/12 Limestone has a number of uses when it undergoes chemical reactions. There are two reactions to know: 1) Firstly, a THERMAL _________________ reaction is used to break the calcium carbonate down into calcium ______ and _______ __________: HEAT Calcium carbonate calcium oxide + carbon dioxide 2) _____ is then added to produce calcium __________: WATER Calcium oxide calcium hydroxide Words – hydroxide, decomposition, carbon dioxide, water, oxide
  • 30. The “Limestone Cycle” 06/11/12 Calcium Carbonate CO2 (limestone) Step 4: add CO2 Step 1: heat Calcium Hydroxide solution Calcium Oxide Step 3: add Step 2: more water add a little and filter water Calcium Hydroxide
  • 31. 06/11/12 Uses of these Calcium compounds Calcium carbonate (limestone), calcium oxide and calcium hydroxide have a number of uses: 1) Neutralising acidic soil – calcium carbonate, calcium hydroxide and calcium oxide are _______ and can be used to ________ soil acidity to help ______ growth. 2) Removing pollutants – calcium carbonate can be used as a “_______” to remove acidic gases from a coal- fired power station’s waste products, helping prevent ____ _____. Words – acid rain, alkaline, plant, scrubber, neutralise
  • 32. 06/11/12 Thermal decomposition of carbonates Limestone undergoes thermal decomposition when heated. The same happens to other carbonates. For example, consider copper carbonate: Copper carbonate (green) turns into copper oxide (black) Limewater Limewater goes cloudy due to carbon dioxide being made Copper carbonate copper oxide + carbon dioxide
  • 33. Topic 3 – Acids 06/11/12 Indigestion Learning Objective: Be able to explain why stomach acid is produced and how antacids are used to neutralise the excess acid that causes indigestion. Starter: Write down as many facts you know about acids, alkalis and neutralisation.
  • 35. Neutralisation reactions 06/11/12 When acids and alkalis react together they will NEUTRALISE each other: Sodium hydroxide Hydrochloric acid Na OH H Cl The sodium replaces the hydrogen from HCl Na Cl H 2O Sodium chloride Water
  • 36. Neutralisation experiment 06/11/12 In this experiment we mixed sodium hydroxide (an _____) and hydrochloric acid together and they ________ each other. The equation for this reaction is… Sodium hydroxide + hydrochloric acid sodium chloride + water A ____ was formed during the reaction, and we could have separated this by __________ the solution. The salt that we formed depended on the acid: • Hydrochloric acid will make a CHLORIDE • Nitric acid will make a _________ • Sulphuric acid will make a _________ Words – nitrate, neutralised, alkali, sulphate, salt, evaporating
  • 37. Stomach Acid 06/11/12 Hydrochloric acid is used in the stomach to help _______ and to kill ______. If we eat too many “rich” foods our stomachs create too much ____ – this is called ______. This acid needs to be neutralised by taking indigestion tablets. Indigestion tablets contain substances such as _______ that neutralise excess stomach acid. Words – digestion, indigestion, acid, alkalis, bacteria
  • 38. Topic 3 – Acids 06/11/12 Neutralisation Learning Objective: Be able to explain how acids are neutralised Starter: Complete the following word equations: Hydrochloric Acid + Sodium Hydroxide Hydrochloric Acid + Calcium Carbonate Sulphuric Acid + Aluminium Hydroxide
  • 40. Neutralisation reactions 06/11/12 A neutralisation reaction occurs when an acid reacts with an alkali. An alkali is a metal oxide or metal hydroxide dissolved in water. ACID + ALKALI SALT + WATER O Cl H Na H Cl Na O H H Copy and complete the following reactions: 1) Sodium hydroxide + hydrochloric acid 2) Calcium hydroxide + hydrochloric acid 3) Sodium hydroxide + sulphuric acid 4) Magnesium hydroxide + sulphuric acid
  • 41. Making salts 06/11/12 Whenever an acid and alkali neutralise each other we are left with a salt, like a chloride or a sulphate. Complete the following table: Hydrochloric Sulphuric acid Nitric acid acid Sodium Sodium hydroxide chloride + water Potassium Potassium hydroxide sulphate + water Calcium Calcium hydroxide nitrate +
  • 42. Using different bases 06/11/12 A metal oxide base: Acid + metal oxide natural salt solution + water heat Suphuric acid + copper oxide copper sulphate + water H2SO4(aq) + CuO(s) heat CuSO4(s) + H2O(l) A metal carbonate base: Acid + metal carbonate natural salt sol n + water + CO2 heat Sulphuric acid + calcium carbonate calcium sulphate + water + CO 2 H2SO4(aq) + CaCO3(s) heat CaSO4(aq) + + H20(l) + CO2(g)
  • 43. 06/11/12 Reactions of metals carbonates with acid A metal carbonate is a compound containing a metal, carbon and oxygen. METAL CARBONATE + ACID SALT + CARBON DIOXIDE + WATER Mg O H Cl O Cl Mg O C C H H O O H Cl Cl O Copy and complete the following reactions: 1) Magnesium carbonate + hydrochloric acid 2) Calcium carbonate + hydrochloric acid 3) Sodium carbonate + sulphuric acid
  • 44. 06/11/12 Reactions of metal oxides with acid A metal oxide is a compound containing a metal and oxide. They are sometimes called BASES. For example: O O Al O Na O Mg Na Al O Magnesium oxide Sodium oxide Aluminium oxide METAL OXIDE + ACID SALT + WATER H Cl Mg O Cl H Mg Cl O H H Cl Copy and complete the following reactions: 1) Magnesium oxide + hydrochloric acid 2) Calcium oxide + hydrochloric acid 3) Sodium oxide + sulphuric acid
  • 45. Electrolysis of Hydrochloric Acid 06/11/12 Positive electrode + H+ - Negative electrode + - + Cl- - Hydrochloric + H+ - Cl- acid H+ Cl-
  • 46. Testing for Hydrogen 06/11/12 “POP”
  • 47. Testing for Chlorine 06/11/12 Chlorine “bleaches” damp indicator paper. It is also a toxic gas so don’t breathe it! This leads to problems when it comes to large-scale manufacture of chlorine gas.
  • 48. Topic 3 – Acids 06/11/12 The Importance of Chlorine Learning Objective: Be able to produce a mind map to show how chlorine is produced, what chlorine is used for and the potential problems with chlorine. importance and the show what the uses Starter: Complete the true and false statements about chlorine.
  • 50. Electrolysis of seawater 06/11/12 Seawater is a mixture of water and salt (sodium chloride) and we can electrolyse it to produce chlorine and other useful products: Chlorine gas (Cl2) Hydrogen gas (H2) Sodium chloride solution (seawater) NaCl(aq) Sodium hydroxide (NaOH(aq)) Positive Negative electrode electrode
  • 51. Uses of chlorine 06/11/12 Polyvinylchloride (PVC) is made up of lots of monomers of vinyl chloride (chloroethene): H Cl H Cl H H H H C C C C C C C C H H H H H H H H Chloroethene Lots more Polyvinylchloride (PVC) monomer Chloroethene monomers Chlorine is also used in the manufacture of bleach. Sodium hydroxide is reacted with chlorine to form sodium hypochlorite (bleach): Cl2 + 2 NaOH → NaCl + NaClO + H2O
  • 52. Topic 3 – Acids 06/11/12 Electrolysis of Water Learning Objective: Be able to explain what are the products from the electrolysis of water and how to test for these gases. Starter: How would you test for Hydrogen, Chlorine, Carbon Dioxide and oxygen gas?? Write it down
  • 54. Electrolysis of Water 06/11/12 Water is two atoms of hydrogen and one atom of oxygen. It can be electrolysed to break it down: H O H Oxygen gas (O2) Hydrogen gas (H2) Water H 2O Positive Negative electrode electrode
  • 55. Testing for Oxygen 06/11/12 Oxygen will relight a glowing splint
  • 56. 06/11/12 Topic 4 – Obtaining and Using Metals Ores Learning Objective: Be able to explain how metals are extracted using the reactivity series Starter: What is the reactivity series??
  • 58. Reactivity series demonstration • All metal elements have a different reactivity. • Some such as sodium are very reactive even in air. • Others such as gold are extremely unreactive. • Watch the demonstration and think about which elements are more reactive.
  • 59. Finding an order? • Can you place these elements a list of reactivity with most reactive a the top and least at the bottom? Sodium Sodium Copper Copper Zinc Zinc Magnesiu Magnesiu m m Gold Gold Iron Iron
  • 60. Extracting Metals 06/11/12 Some definitions: A METAL ORE is a mineral or mixture of minerals from which it is “economically viable” to extract some metal. Most ores contain METAL OXIDES (e.g. rust = iron oxide). To “extract” a metal from a metal oxide we need to REDUCE the oxygen. This is called a REDUCTION reaction. To put it simply: Iron “Reduce” the oxygen Iron Oxide ore to make iron
  • 61. How do we do it? 06/11/12 Potassium Metals ABOVE CARBON, because Sodium of their high reactivity, are extracted by ELECTROLYSIS, Calcium which is very expensive! Magnesium Metals BELOW CARBON are Aluminium extracted by heating them with Carbon carbon in a BLAST FURNACE. This is a “displacement reaction” Zinc Iron Tin Carbon Iron Oxide Lead Copper These LOW REACTIVITY metals won’t Silver need to be extracted because they are Gold SO unreactive you’ll find them on their own, not in a metal oxide Platinum
  • 62. Extracting metals • A metal can be extracted from a compound by reacting with an element higher up in the reactivity series. • So for example copper is more reactive than silver. • If we add copper metal to silver nitrate compound we make silver metal. • Draw a picture of this in your book.
  • 63. Extracting iron • Iron ore (haematite) is iron oxide. • To make iron we need to remove the oxygen. • This process is called REDUCTION Copy down this equation Iron oxide + carbon  Iron + Carbon Iron oxide + carbon  Iron + Carbon dioxide dioxide
  • 64. Extracting Iron from its ore • Carbon can also be put into the reactivity series and is higher (more reactive) than iron. • This means iron can be extracted from its ore using carbon.
  • 65. Notes to copy and complete Metals that are ______ reactive than carbon in the reactivity series can be ___________ from their oxides by _________ with ________. Iron oxide is reduced in the _________ ________ to make iron. [extracted, reduction, carbon, less, blast furnace]
  • 66. What are Ores? Most metals are too …………… to exist on their own in the ground. Instead they exist combined with other elements (typically o……….. or sulphur) as ……………….. called …………. A few metals are so ……………….. that they exist uncombined, as ……….metals e.g. gold, ……………….. Metal Name of ore Compound in ore Words: Aluminium Bauxite Aluminium oxide (Al2O3) ores silver reactive oxygen compounds unreactive pure
  • 67. Displacement Reactions 1. Iron + Copper Sulphate  Iron Sulphate + Copper 2. Copper + Silver Nitrate  Copper Nitrate + Silver 3. Sodium + Zinc Carbonate  Sodium Carbonate + Zinc 4. Potassium + Iron Oxide  Potassium Oxide + Iron 5. Gold + Copper Carbonate  Gold + Copper Carbonate No reaction! Can you figure out why?
  • 68. How do we extract metals from ores? Watch this video clip: http://jchemed.chem.wisc.edu/JCESoft/CCA/samples/cca7therm It is called the thermite reaction. The symbol equation is: Fe2O3 + Al  Al2O3 + Fe 1. Copy out the symbol equation and write the word equation underneath. 2. Why does this reaction happen? 3. Do you think that it’s a commercially viable way of extracting iron from its ore? Explain your answer.
  • 69. So how is it done? Potassium Sodium Magnesium The reactivity series of metals… Aluminium Zinc Carbon can be used to extract some metals from Iron their ores e.g. Copper Copper oxide + Carbon  Copper + Carbon dioxide Silver The copper oxide has lost oxygen. This is called a Gold reduction reaction.
  • 70. Potassium Extracted from their ores by Sodium electrolysis (using electricity) Aluminium Carbon Zinc Extracted from their ores by Iron reduction by carbon Copper Silver No extraction necessary – found Gold pure in the ground.
  • 71. Extracting metals 06/11/12 1) What is an ore? 2) In what form are metals usually found in the Earth? 3) How do you get a metal out of a metal oxide? 4) What is this type of reaction called? Type of metal Extraction process Examples High reactivity (i.e anything above carbon) Middle reactivity (i.e. anything below carbon) Low reactivity
  • 72. 06/11/12 Extracting Aluminium Aluminium has to be extracted from its ore by electrolysis. This is because aluminium is very ___________ and so it cannot be extracted using ______. The amount of energy and _____ required to extract aluminium and other metals is very high and so ________ is a much better option. Words – reactive, recycling, money, carbon
  • 73. Copper, Aluminium and Titanium 06/11/12 Metal Uses and why Extraction Problems method Copper Electrical wires – Electrolysis Limited supply good conductor Gold Jewellery – None needed – Limited supply attractive and its unreactive so and very resistant to you find it in the expensive corrosion Earth as gold Aluminium and Planes – light and Complicated and Expensive and titanium corrosion expensive difficult to resistant extract
  • 74. 06/11/12 Topic 4 – Obtaining and Using Metals Oxidation and Reduction Learning Objective: Be able to explain the terms oxidation and reduction and relate it to equations Starter: If reduction means removing the oxygen what do you think oxidation means??
  • 77. Rusting 06/11/12 Rust is a hydrated form of iron oxide. It is formed when iron and/or steel combines with oxygen and water in an oxidation reaction: Iron + oxygen + water hydrated iron (III) oxide
  • 78. Rusting 06/11/12 Task: To investigate what causes rusting Tube 1 – Tube 2 – Tube 3 – Tube 4 – drying boiled water + air water + air agent water + salt
  • 79. Rusting 06/11/12 Task: To investigate what causes rusting No rust No rust Rust Lots of rust Iron + oxygen + water hydrated iron oxide
  • 80. Reducation and Oxidation 06/11/12 Some examples of reduction: heat Aluminium + iron oxide aluminium oxide + iron 2Al(s) + Fe2O3(s) heat Al2O3(s) + 2Fe(s) heat Lead oxide + carbon lead + carbon dioxide 2PbO(s) + C(s) heat 2Pb(s) + CO2(s) An example of oxidation: heat Magnesium + oxygen magnesium oxide Mg(s) + O2(s) heat 2MgO(s)
  • 81. More on Redox Reactions 06/11/12 Basically, during a redox reaction electrons are either lost or gained: The Golden Rule: OILRIG Oxidation Is Loss (of electrons) Reduction Is Gain (of electrons) For example: Fe Fe2+ These reactions both involve the loss of 2Cl- Cl2 electrons – they are Oxidation reactions Fe2+ Fe These reactions both involve the gain of electrons – they are Reduction reactions Cl2 2Cl-
  • 82. C1.18 Reactions . Is the substance in red being oxidised or reduced in the following reaction? magnesium + oxygen → magnesium oxide Oxidised
  • 83. C1.18 Reactions . Is the substance in red being oxidised or reduced in the following reaction? lead oxide + carbon → lead + carbon dioxide Reduced
  • 84. C1.18 Reactions Is the substance in red being oxidised or reduced in the following reaction? magnesium + hydrogen → magnesium + water oxide Reduced
  • 85. C1.18 Reactions Is the substance in red being oxidised or reduced in the following reaction? nickel + oxygen → nickel oxide Oxidised
  • 86. C1.18 Reactions Is the substance in red being oxidised or reduced in the following reaction? 4 Na + O2 → 2 Na2O Oxidised
  • 87. C1.18 Reactions Is the substance in red being oxidised or reduced in the following reaction? Cr2O3 + 2 Al → 2 Cr + Al2O3 Reduced
  • 88. 06/11/12 Topic 4 – Obtaining and Using Metals Recycling Metals Learning Objective: Be able to explain the importance of recycling Starter: Explain how recycled is carried out in Newham
  • 90. Recycling 06/11/12 Why recycle metals? 1) Less space will be needed for landfill sites 2) Recycled metals only need about 1/10th of the energy to produce compared to producing new metals 3) Recycling saves on raw materials 4) Less excavation and mining costs
  • 91. 06/11/12 Topic 4 – Obtaining and using metals Properties of metals and Alloys Learning Objective: Explain why certain metals are used in relation to their properties. Describe ways metal properties can be improved. Starter: Sort out he properties of the metals on the worksheet.
  • 93. C1.20 Why use that metal? Why are electrical cables made from copper? © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original.
  • 94. C1.20 Why use that metal? Why are aeroplanes made with a lot of aluminium? © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original.
  • 95. C1.20 Why use that metal? Why is jewellery made from gold? © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original.
  • 96. C1.20 Why use that metal? Why are cars made from steel? © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original.
  • 97. C1.20 Why use that metal? Why are cooking pans made from aluminium? © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original.
  • 98. C1.20 Why use that metal? Why is gold used on audio cables? © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original.
  • 99. C1.20 Why use that metal? Why are hot water pipes made from copper? © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original.
  • 100. C1.20 Why use that metal? Why are bridges made from steel? © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original.
  • 101. C1.20 Why use that metal? Why is aluminium used in heat sinks for microprocessors? © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original.
  • 102. © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original.
  • 103. 06/11/12 Using impurities to strengthen Iron In pure iron all impurities are removed. This makes the iron soft: Adding 1% impurities makes the iron much stronger:
  • 104. Alloys 06/11/12 Steel is an “alloy” – i.e. a mixture of metals. Here are other alloys: Gold mixed with Aluminium mixed Aluminiun mixed copper with magnesium with chromium and copper
  • 105. 06/11/12 Making steel Strong Strength Hardness Amount of Weak carbon 0.5% 1% 1.5% added (%) Steel with a low Steel with a high Steel with chromium carbon content is carbon content is and nickel is called easily shaped strong but brittle stainless steel
  • 106. Smart Alloys 06/11/12 A “smart alloy” is one that can “remember” its original state after being bent or stretched. These glasses are made from a “smart” material – if they are bent they will return to their original shape. They could be made from an alloy called “nitinol” (an alloy of nickel and titanium) which can be bent but then returned to its original shape simply by heating to its “transformation temperature”.
  • 107. Gold alloys 06/11/12 Gold can be mixed with other metals to make alloys with different properties. For example: 24-Carat gold 9-Carat gold “Pure gold” – 99.99% of the atoms “9 carat gold” – around 9/24ths in this bar are gold atoms (fineness of the atoms in these earrings off 999.9). Pure and malleable but are gold atoms. Harder than soft. pure gold but less malleable.
  • 108. Materials in a Car 06/11/12 Copper wires Glass Nylon windscreen seatbelts Plastic trim Steel body Alloy wheels
  • 109. Iron or aluminium? 06/11/12 Aluminium: Does not corrode Less dense so it’s lighter Iron: Cheaper than aluminium Magnetic so easily recycled Most cars are made from steel (an alloy of carbon) From 2015 95% of a car will have to be made from recycled material. What are the advantages of this?
  • 110. 06/11/12 Topic 5 – Fuels Crude Oil Learning Objective: Explain how crude oil is formed and its uses. Starter: What elements are contained in Hydrocarbons
  • 112. Fuels 06/11/12 Fuels are substances that can be used to release useful amounts of energy when they burn, e.g. Wood Oil Gas Coal These fuels are called “fossil fuels” and are described as being “non-renewable”.
  • 113. Crude Oil 06/11/12
  • 114. 06/11/12 Topic 5 – Fuels Crude Oil fractions Learning Objective: Explain how hydrocarbon fractions are separated. Starter: Write down three facts you remember form last lesson
  • 116. 06/11/12 Hydrocarbons and crude oil Crude oil is a mixture of HYDROCARBONS (compounds made up of carbon and hydrogen). Some examples: H H Longer chains mean… Increasing length H C C H H H 1. Less ability to flow Ethane 2. Less flammable H H H H H C C C C H 3. Less volatile H H H H 4. Higher boiling point Butane
  • 117. Distillation revision 06/11/12 This apparatus can be used to separate water and ink because they have different _____ ______. The ______ will evaporate first, turn back into a _______ in the condenser and collect in the _______. The ink remains in the round flask, as long as the _______ does not exceed ink’s boiling point. This method can be used to separate crude oil. Words – temperature, boiling points, water, beaker, liquid
  • 118. . 06/11/12 Sort them into benefits and drawbacks of using oil 1 Accidents with oil wells or oil tankers can pollute the sea and kill wildlife. 2 Cars that run on petrol are much more convenient than battery-powered cars. 3 Burning fossil fuels produces carbon dioxide and other polluting gases. 4 We can make lots of different chemicals out of the substances in crude oil. 5 Crude oil will run out one day. 6 Bitumen is very useful for making roads. 7 We need oil to lubricate engines and other moving machines. 8 Petrol can cause explosions if it is not transported and stored correctly.
  • 119. Fractional distillation 06/11/12 Crude oil can be separated by fractional distillation. The oil is evaporated and the hydrocarbon chains of different lengths condense at different temperatures: Fractions with low boiling points condense at the top Fractions with high boiling points condense at the bottom
  • 120. 9Hb How fractional distillation works C1.23 Fractional distillation How fractional distillation works © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free.
  • 121. 9Hb How fractional distillation works C1.23 Fractional distillation Crude oil is a mixture of different hydrocarbon molecules. The molecules have different numbers of carbon and hydrogen atoms in them. Some of the different molecules in crude oil. © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free.
  • 122. 9Hb How fractional distillation works C1.23 Fractional distillation Molecules of different sizes have to be separated before oil can be used. This is done in an oil refinery. The process of separating crude oil is called fractional distillation. The different mixtures produced An oil refinery. The tall towers are are called fractions. 'fractionating columns'. © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free.
  • 123. 9Hb How fractional distillation works C1.23 Fractional distillation Fractional distillation works because the different molecules in crude oil have different boiling points. There are tiny forces of attraction between all molecules. The longer the molecule, the bigger this force. So long molecules tend to stick together more than small ones. The bigger the force, the more energy is needed to allow the molecules to break away from the liquid and form a gas. So longer molecules have higher boiling points. © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free.
  • 124. 9Hb How fractional distillation works C1.23 Fractional distillation gases The diagram shows a fractionating column. It is hotter at the petrol bottom than at the column top. getting cooler kerosene diesel oil Click on a number to find out more. fuel oil bitumen © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free.
  • 125. 9Hb How fractional distillation works C1.23 Fractional distillation gases 1 Crude oil is heated petrol until it boils. The gas column is fed into the bottom getting cooler of the fractionating kerosene column. diesel oil fuel oil bitumen Back to fractionating column © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free.
  • 126. 9Hb How fractional distillation works C1.23 Fractional distillation gases 2 The hot crude oil vapour goes petrol into the fractionating column. column getting It starts to cool down. Fuel oil, cooler kerosene waxes and bitumen condense and run out of the pipe at the diesel oil bottom. These fractions have the fuel oil longest molecules and the highest boiling points. bitumen Back to fractionating column © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free.
  • 127. 9Hb How fractional distillation works C1.23 Fractional distillation gases 3 The rest of the crude oil petrol gas rises up the column. column It cools as it rises. getting cooler kerosene The largest molecules left in the gas condense next. diesel oil They fall onto the 'tray'. fuel oil bitumen Back to fractionating column © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free.
  • 128. 9Hb How fractional distillation works C1.23 Fractional distillation gases 4 The next longest molecules petrol condense here. column Each set of trays collects getting cooler kerosene condensed molecules with carbon numbers in a diesel oil particular range. fuel oil bitumen Back to fractionating column © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free.
  • 129. 9Hb How fractional distillation works C1.23 Fractional distillation gases 5 The condensed liquids petrol are removed through pipes. Some of them go column getting to further fractionating cooler kerosene columns to separate them further. diesel oil fuel oil bitumen Back to fractionating column © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free.
  • 130. 9Hb How fractional distillation works C1.23 Fractional distillation gases 6 The smallest molecules petrol in crude oil are gases at normal temperatures. column getting cooler kerosene These gases are removed from the top of diesel oil the column. fuel oil bitumen Back to fractionating column © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free.
  • 131. 06/11/12 Match up the names and uses Fractions Gases Fuel oil Kerosene Petrol Bitumen Diesel oil Uses Fuel for some cars Fuel for some cars Making roads Cooking in homes Fuel for large ships Fuel for aircraft Heating homes Fuel for some trains Fuel for some power Making roofs waterproof stations
  • 133. 06/11/12 Topic 5 – Fuels Combustion Learning Objective: •Able to explain what is produced when hydrocarbons burn. Starter: Draw a brainstorm to show everything you remember about crude oil.
  • 135. Burning Hydrocarbons 06/11/12 Burning hydrocarbons will produce water, carbon dioxide and energy: H H O O O O H H C C H O H O O H O H Methane + Oxygen Carbon + Water dioxide In this reaction the hydrocarbon is oxidised.
  • 136. Testing for Carbon Dioxide 06/11/12 Gas Limewater Limewater turns milky/cloudy
  • 137. Burning Hydrocarbons 06/11/12 H H O O O H Lots of C O C H oxygen: H O H O O H O H Methane + Oxygen Carbon + Water dioxide H O H H O H O O C O H C H H Some H O O oxygen: H H C O H O H C O O O H H H H Methane + Oxygen Carbon + Water monoxide H O H H H Little C O C O O oxygen: H H H H Methane + Oxygen Carbon + Water
  • 138. C1.24 Balancing equations We can represent what happens in chemical reactions using symbol equations. We use a symbol (of one or two letters) to represent atoms of different elements. We also use symbols to show how many atoms of different kinds are joined together to make a compound. © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free.
  • 139. C1.24 Balancing equations For example: Hydrogen chloride molecules are made from one atom of hydrogen joined to one atom of chlorine. HCl H Cl Water molecules are made from one atom of oxygen joined to two atoms of hydrogen. The little '2' shows there are two hydrogen atoms. H2O H O H © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free.
  • 140. C1.24 Balancing equations Hydrogen gas reacts with chlorine gas to form hydrogen chloride. Hydrogen and chlorine gases both exist as pairs of atoms. H Cl H + H Cl Cl H2(g) + Cl2(g) HCl(g) © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free.
  • 141. C1.24 Balancing equations But this isn't quite right yet – the reactants have two atoms of hydrogen and two of chlorine. Atoms are not created or destroyed in a reaction, so we must have two hydrogen atoms and two chlorine atoms in the products. H Cl H Cl H + Cl H Cl H2(g) + Cl2(g) 2HCl(g) © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free.
  • 142. C1.24 Balancing equations The 2 in front of the HCl in the symbol equation shows that there are two complete molecules of hydrogen chloride. H Cl H Cl H + Cl H Cl H2(g) + Cl2(g) 2HCl(g) © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free.
  • 143. C1.24 Balancing equations Hydrogen and oxygen react to form water. H O O H + H H O H2(g) + O2(g) H2O(g) © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free.
  • 144. C1.24 Balancing equations There are more oxygen atoms in the reactants than the products, so we must have made more than one molecule of water. H O H O O H + H H H O H2(g) + O2(g) 2H2O(g) © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free.
  • 145. C1.24 Balancing equations But now there are more hydrogen atoms in the products than in the reactants. We must have started with more than one hydrogen molecule. H O H H O H O H + H H H O 2H2(g) + O2(g) 2H2O(g) © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free.
  • 146. C1.24 Balancing equations This is now a balanced symbol equation to show the reaction of hydrogen and oxygen to form water. H O H H O H O H + H H H O 2H2(g) + O2(g) 2H2O(g) © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free.
  • 147. C1.24 Balancing equations Try these examples. Click on an example to see how to work out the balanced symbol equation. Methane (CH4) reacts with oxygen to form carbon dioxide and water. Magnesium reacts with oxygen to form magnesium oxide (MgO). © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free.
  • 148. C1.24 Balancing equations Methane (CH4) reacts with oxygen to form carbon dioxide and water. O H O C H O H C H + + O H H O CH4(g) + O2(g) CO2 + H2O(g) © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free.
  • 149. C1.24 Balancing equations There are more oxygen atoms in the products than the reactants, so we must have started with more oxygen. O O H O C H O H C H + + O H H O O CH4(g) + 2O2(g) CO2 + H2O(g) © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free.
  • 150. C1.24 Balancing equations Now there are more oxygen atoms in the reactants than the products. The reaction must produce more water molecules. O O H O H O C H H C H + + O H O H O O H CH4(g) + 2O2(g) CO2 + 2H2O(g) © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free.
  • 151. C1.24 Balancing equations The equation is balanced. You can check this by counting up the numbers of atoms on each side of the equation. O O H O H O C H H C H + + O H O H O O H CH4(g) + 2O2(g) CO2 + 2H2O(g) © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free.
  • 152. C1.24 Balancing equations Magnesium reacts with oxygen to form magnesium oxide (MgO). Mg O Mg + O O Mg(s) + O2(g) MgO(s) © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free.
  • 153. C1.24 Balancing equations There are more oxygen atoms in the reactants than the products, so the reaction must produce more magnesium oxide. Mg O Mg O + O Mg O Mg(s) + O2(g) 2MgO(s) © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free.
  • 154. C1.24 Balancing equations And we must have started with more than one magnesium atom… Mg O Mg O Mg + O Mg O 2Mg(s) + O2(g) 2MgO(s) © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free.
  • 155. C1.24 Balancing equations Now the symbol equation is balanced. Mg O Mg O Mg + O Mg O 2Mg(s) + O2(g) 2MgO(s) © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free.
  • 156. C1.24 Questions and answers 1 Give an example of a hydrocarbon fuel. A: Any named hydrocarbon that can be used as a fuel – petrol, diesel, kerosene etc. 2 Why is combustion an example of an oxidation reaction? A: The reaction combines a fuel with oxygen. © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not 156 copyright free. This document may have been altered from the original.
  • 157. C1.24 Questions and answers 3 Look at Figure B. What is the source of oxygen that allows the candle to burn? A: Air © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not 157 copyright free. This document may have been altered from the original.
  • 158. C1.24 Questions and answers 4 In Figure B, which part of the apparatus shows that: a carbon dioxide is produced A: Limewater b oxygen is produced? A: Copper sulfate © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not 158 copyright free. This document may have been altered from the original.
  • 159. C1.24 Questions and answers 5 Butane is a hydrocarbon compound found in crude oil. Write a word equation for the combustion of butane. A: Butane + oxygen → carbon dioxide + water © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not 159 copyright free. This document may have been altered from the original.
  • 160. C1.24 Questions and answers 6 Limewater is calcium hydroxide solution, Ca(OH)2. It forms calcium carbonate,CaCO3, and water when it reacts with carbon dioxide. a Write a word equation for this reaction. A: Calcium hydroxide solution + carbon dioxide → calcium carbonate + water © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not 160 copyright free. This document may have been altered from the original.
  • 161. C1.24 Questions and answers b Why does limewater go milky when carbon dioxide is bubbled through it? A: The calcium carbonate formed is a solid; the cloudiness is due to tiny particles of solid calcium carbonate (a precipitate) in the water. c Write a balanced equation for the reaction. A: Ca(OH)2(aq) + CO2(g) → CaCO3(s) + H2O(l) © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not 161 copyright free. This document may have been altered from the original.
  • 162. C1.24 Questions and answers 7 Jose says, ’Burning petrol produces nitrogen oxides and water’. Explain how you can tell he is wrong just by using the fact that petrol is a mixture of hydrocarbon molecules. A: Answers may include: Petrol compounds are hydrocarbons so they only contain carbon and hydrogen atoms; burning uses only oxygen from the air; neither of the reactants contain nitrogen, so a compound contains nitrogen cannot be one of the products of the reaction. © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not 162 copyright free. This document may have been altered from the original.
  • 163. 06/11/12 Topic 5 – Fuels Incomplete combustion and Acid Rain Learning Objective: Explain what happens if there is not enough oxygen for burning. Explain the consequences of Acid Rain Starter: Write a balanced equation to show combustion.
  • 165. Incomplete Combustion 06/11/12 As well as producing carbon monoxide, incomplete combustion can also produce soot: H O H H H Little C O C O O oxygen: H H H H Methane + Oxygen Carbon + Water “Soot”
  • 166. 06/11/12 Why Carbon Monoxide is Dangerous Basically, carbon monoxide “sticks” to red blood cells instead of oxygen, causing anybody inhaling it to essentially suffocate: CO 1) Carbon Monoxide is breathed in 2) The molecule “sticks” to red blood cells instead of oxygen 3) The red blood cells transport the “carboxyhaemoglobin” molecule to the rest of the body and the body’s cells are starved of the oxygen needed for respiration. Carbon monoxide is odourless, colourless and non-irritating so it’s very difficult to detect!
  • 167. Burning Fossil Fuels 06/11/12 Burning fossil fuels like oil and coal causes pollution. Oil contains carbon: H H O O O O H H C C H O H O O H O H Carbon dioxide is a “greenhouse gas” – it helps cause global warming Coal contains carbon, sulfur and other particles: sulfur + oxygen sulfur dioxide Sulfur dioxide causes acid rain. Other particles can cause “global dimming” – sunlight is absorbed by the particles in the atmosphere.
  • 169. C1.26 Questions and answers 1 Why is rain normally slightly acidic? A: Contains dissolved carbon dioxide from the air. © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not 169 copyright free. This document may have been altered from the original.
  • 170. C1.26 Questions and answers 2 A What is ‘acid rain’? A: Rain that is more acidic than normal. b What causes acid rain? A: Acidic gases such as sulfur dioxide and nitrogen oxides dissolved in rainwater. © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not 170 copyright free. This document may have been altered from the original.
  • 171. C1.26 Questions and answers 3 What effect does acid rain have on: a the water in rivers and lakes A: Makes it more acidic (lowers pH). b organisms that live in rivers and lakes A: Can harm or kill them. c trees A: Damages them and can kill them. d stone buildings and statues? A: Weathers the stone by chemical reactions, so it breaks up and erodes faster. © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not 171 copyright free. This document may have been altered from the original.
  • 172. C1.26 Questions and answers 4 Limestone (calcium carbonate) can be used to neutralise the sulfuric acid that makes lakes acidic. Write a word equation for this neutralisation reaction. A: Calcium carbonate + sulfuric acid → calcium sulfate + water + carbon dioxide © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not 172 copyright free. This document may have been altered from the original.
  • 173. C1.26 Questions and answers 5 Describe how acid rain forms and describe two ways in which acid rain in Europe has been reduced. A: Answers may include: Sulfur compounds in burning fossil fuels form sulfur dioxide, which dissolves in rain to form an acidic solution; sulfur impurities can be removed from fuels before they are sold and burnt; for fuels used in power stations, an alternative is to remove the sulfur dioxide from the waste gases in the chimney, after the fuel is burnt – this is done by neutralising the acidic sulfur dioxide gas with calcium carbonate. © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not 173 copyright free. This document may have been altered from the original.
  • 174. 06/11/12 Topic 5 – Fuels Climate change Learning Objective: Explain how human activity affects the earths temperature.
  • 176. Global Warming 06/11/12 Facts: 1) The 10 warmest years of the last century have all occurred within the last 15 years 2) Sea level has risen by between 12 and 24cm in the last 100 years 3) Rainfall has risen by 1%
  • 177. The Greenhouse Effect 06/11/12 We get heat A lot of this heat is from the sun: _______ back into space. However, most of it is kept inside the Earth by a layer of gases that prevent the heat escaping by _______ and then re-radiating it back again. This is called the _________ Effect. It has always been around, but is currently being made worse due to: 1) Burning (releasing CO2) 2) __________ (removing trees that remove CO2) 3) Increased micro organism activity (from rotting ______) 4) Cattle and rice fields (they both produce _______) These changes will cause GLOBAL WARMING and RISING SEA LEVELS Words – methane, radiated, absorbing, deforestation, waste, greenhouse
  • 178. 06/11/12 Carbon Dioxide and Global Warming Global levels of Carbon Dioxide in PPM Is there a link?
  • 179. 06/11/12 Reducing the amount of Carbon Dioxide Scientists are trying to reduce the amount of carbon dioxide in the atmosphere through a number of possibilities: 1) “Iron seeding” – this is the process where iron is intentionally put in seawater to help produce more phytoplankton which then increases photosynthetic activity, therefore reducing the amount of CO2 in the atmosphere. Aerial view of phytoplankton near Argentina 2) Converting CO2 into hydrocarbons – carbon dioxide can be converted into hydrocarbons and then stored in the Earth by putting it in such places as old oil fields or coal beds.
  • 180. Reducing Pollution from vehicles 06/11/12 A number of suggestions: 1) Buy a new, smaller, cleaner car 2) Buy a “hybrid” car 3) Convert your car to run on biodiesel 4) Make sure your car has a catalytic converter: Carbon monoxide + oxygen carbon dioxide Nitrogen monoxide + carbon monoxide nitrogen + carbon monoxide 5) Use the train or a bus!
  • 181. 06/11/12 Topic 5 – Fuels Biofuels and choosing fuels Learning Objective: •Explain the advantages and disadvantages of using biofuels •Explain how to choose the best fuel. Starter: What do you know about biofuels
  • 183. Ethanol as a biofuel 06/11/12 Ethanol is an important chemical. Many countries are increasing the amount of ethanol put into their petrol supplies: Ford Escape E85 – runs on 85% ethanol Ethanol is a “clean burning” energy source and produces little or no greenhouse gases. How is it made? The “renewable” way Sugar is produced from standard crops like Sugar ethanol + carbon dioxide sugar cane and corn What’s the point? When ethanol burns it only produces small amounts of carbon dioxide. Making more cars run on ethanol means having less cars that need petrol.
  • 184. C1.28 Photosynthesis and biofuels A fuel is carbon neutral when the amount of carbon dioxide absorbed in making the fuel equals the amount of carbon dioxide produced when it is burned. Are biofuels carbon neutral? © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original.
  • 185. C1.28 Photosynthesis and biofuels Plants use carbon dioxide from the air in photosynthesis. The material in a plant stores carbon atoms that have been taken out of the atmosphere. carbon dioxide © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original.
  • 186. C1.28 Photosynthesis and biofuels Plants can be harvested to be turned into fuel. © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original.
  • 187. C1.28 Photosynthesis and biofuels Plants must be converted to biofuels such as biodiesel before they can be used as fuel for vehicles. This is done in a refinery. © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original.
  • 188. C1.28 Photosynthesis and biofuels The biofuel contains carbon that was originally taken out of the atmosphere by the plants used to make the fuel. © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original.
  • 189. C1.28 Photosynthesis and biofuels When the biofuel is burned in engines, carbon dioxide is put into the atmosphere. carbon dioxide © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original.
  • 190. C1.28 Photosynthesis and biofuels But this carbon dioxide has only recently been taken out of the atmosphere by the plants used to make the fuel. Overall, no carbon dioxide has been added to the atmosphere. Or has it? © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original.
  • 191. C1.28 Photosynthesis and biofuels The machinery used to plant the crops and harvest them needed fuel. Fuel was needed to make fertilisers to help the crops to grow. The refinery used energy to convert the plants to biofuel. Unless all these processes also used biofuels, then the biofuel is not really 'carbon neutral'. © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original.
  • 192. Choosing a biofuel 06/11/12 Does it create How much energy pollution? does it release? Biofuels Is it toxic? How much does it cost? How much land is Does it take more CO2 needed? to tranport it than it takes in from the How easy is it to atmosphere while grow/make? growing?
  • 193. Choosing a fuel 06/11/12 How easily does How much energy it burn? does it release? Which fuel should Is it toxic? you use? How much smoke does it produce? Is it easy to use, store and transport?
  • 194. Hydrogen Fuel Cells 06/11/12 Basically, a hydrogen fuel cell combines hydrogen and oxygen to form water and release energy:
  • 195. Hydrogen Fuel Cells 06/11/12 Advantages of fuel cells Advantages of petrol Hydrogen fuel cells vs Petrol
  • 196. Energy from fuels 06/11/12 Copper calorimeter Water Spirit burner Fuel
  • 197. C1.29 Fuel quiz The answers to all these questions are one or more of: • hydrogen • methane • liquid fuels (such as petrol, kerosene and diesel) • solid fuels (such as coal and wood) © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original.
  • 198. C1.29 Fuel quiz Which fuel or fuels can be sent through pipes? © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not Answer copyright free. This document may have been altered from the original.
  • 199. C1.29 Fuel quiz Which fuel or fuels can be sent through pipes? • hydrogen • methane • liquid fuels (petrol, kerosene, diesel) © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original.
  • 200. C1.29 Fuel quiz Which fuel or fuels are used in cars? © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not Answer copyright free. This document may have been altered from the original.
  • 201. C1.29 Fuel quiz Which fuel or fuels are used in cars? • hydrogen • liquid fuels (petrol, diesel) © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original.
  • 202. C1.29 Fuel quiz Which fuel or fuels are fossil fuels? © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not Answer copyright free. This document may have been altered from the original.
  • 203. C1.29 Fuel quiz Which fuel or fuels are fossil fuels? • methane • liquid fuels (petrol, kerosene, diesel) • solid fuels (coal) © Pearson Education Ltd 2011. Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original.

Editor's Notes

  1. Unsaturated ( contains at least 1 double bond) Plastics ( manufactured polymers)
  2. AT pg 183 first icon. Get pupils to write on whiteboards the name of the monomer and the polymer it makes
  3. Review using AT and pupils add to their notes key properties
  4. Polyethene- it is the only artifical polymer. The others are natural
  5. The vase is a wine bottle, the chair a wheelbarrow, the table a washing drum, the desk a kitchen worktop, the other chair a shopping trolley,
  6. Orange Assessment – pupils to start this in the lesson – write a plan. And finish for homework