chemistry class

1. UNIVERSIDAD AUTÓNOMA DE NUEVO LEON
CIDEB
CHEMISTRY II
 STAGE II: AQUEOUS
SOLUTIONS

2. STAGE 2: AQUEOUS SOLUTIONS
Formative Objective: The student
identifies common solutions in the
surrounding, distinguishes their
composition by calculations of
concentration using theoretical and
experimental data, and recognizes
drinking water as a vital dissolution.

3. ANTIFREEZE SEA WATER STEEL
AIR SOFT DRINKS ITALIAN
DRESSING
FOG SPRAY
DEODORANT
MUDDY
WATER
IRON FILINGS AND
SULFUR
SHAVING
FOAM
STRAWBERRY
JELLY
DENTAL
AMALGAM
MAYONNAISE BLOOD
COPPER
WIRE
CARBON
DIOXIDE
DISTILLED WATER

5. TYPES OF HETEROGENEOUS
MIXTURES
Suspensions
• Mixture containing
particles that settle out
if left undisturbed.
• Pouring a liquid
suspension through a
filter will separate out
the suspended
particles.
• Particles in a
suspension are much
larger than atoms and
can settle out of
solution
Colloids
• Heterogeneous mixture
of intermediate-sized
particles (between 1
and 1000 nm in
diameter.
• Particles do not settle
out.
• The dispersed particles
make random
movements called
Brownian motion.
• Present Tyndall effect.

6. HOMOGENEOUS MIXTURES:
SOLUTIONS
 Homogeneous mixtures that contain two or more
substances called the solute and the solvent.
 Atoms
 Ions
 Molecules
 SOLUTE: the substance being dissolved (the
substance with the lesser amount)
 SOLVENT: the dissolving medium; the component
whose physical state is retained (the substance
present in the greater amount).

7. TYPES OF SOLUTIONS

8. FORMING SOLUTIONS
 Soluble: A substance that dissolves in a solvent;
(sugar in water)
 Insoluble: A substance that does not dissolve in a
solvent (sand in water).
 Miscible: Two liquids that are soluble in each other
in any proportion, (such as the antifreeze)
 Immiscible Two liquids that can be mixed together
but separate shortly after (Oil and vinegar

9. PROPERTIES OF TRUE SOLUTIONS
 The particles of solute are the size of molecules or ions.
 The mixture does not separate on standing.
 The mixture does not separate by common fiber filter. The
entire solution will pass through the filter.
 Once it is completely mixed, the mixture is homogeneous. If
you take a sample of the solution from any point in the
solution, the proportions of the materials will be the same.
 The mixture appears clear rather than cloudy. It may have
some color to it, but it seems to be transparent otherwise.
The mixture shows no Tyndall effect.
 The solution of ionic materials into water will result in an
electrolyte solution.
 The solution shows an increase in boiling point as the
amount of solute is increased.

10. SOLUBILITY AND SOLVATION
PROCESS

11. THINK ABOUT IT...
 Why salt is soluble in water and oil is not?
 While preparing lemonade it is the same to:
 Use Cold water / room temperature water
 Use Sugar in cubes / granulated sugar
 Stirring the mix / Not stirring

12. THE SOLVATION PROCESS
 The process of surronding solute particles with
solvent particles to form a solution is called
SOLVATION.
 If solvation occurs in water is called Hydration.
“Like dissolves like”

13.  http://glencoe.mcgraw-hill.
com/olcweb/cgi/pluginpop.cgi?it=swf::550::400::/
sites/dl/free/0078807239/602901/Dissolution_of_C
mpds_fig_13_15.swf::Dissolution of compounds

14. SOLUBILITY
 Water molecules surrond
the ions of the solute:
Hydration.
 Each ion becomes
completely separated
from the solid crystal and
become hydrated.
 Water solubility
depends on the
formation of hydrogen
bonds.
 Molecules containing a
high proportion of
nitrogen or oxygen
atoms usually dissolve
in water because the
formation of hydrogen
bonds
Ionic Compounds
Covalent Compounds

15. FACTORS THAT AFFECT SOLVATION
• Stirring allows new collisions between
solute and solvent particles
• Stirring increases the speed of
dissolving
Agitation
• Breaking solute into small pieces
increases its surface area;
• The greater the surface area is, the
quicker it will dissolve
Surface area
• For solids; solubility increases with
temperature.
• For gases; solubility decreases with
temperature
Temperature

16. SOLUBILITY OF GASES
• Gases are less soluble at
higher temperatures than at
lower temperatures.
• As a solution’s temperature
increases, the solubility of a
gaseous solute decreases.
Temperature
• The solubility of a gas in
any solvent increases as its
external pressure (the
pressure above the
solution) increases.
Pressure

17. 1. Process of
surronding solute
particles with
solvent particles to
form a solution.
2. Kind of compounds
where solvation
occurs when water
molecules
surround ions.
3. Kind of compound
where solvation
occurs forming
hydrogen bonds.
4. Overall energy
change during the
solution formation
5. Factors that affect
solvation (3)
REVIEW

18. SOLUBILITY: MEASURE OF HOW MUCH OF THE
SOLUTE CAN BE DISSOLVED INTO THE SOLVENT.
Unsaturated solutions
• Contains less dissolved solute for a given temperature and pressure
than a saturated solution; more solute can be dissolved in an
unsaturated solution.
Saturated solutions
• Contains the maximum amount of dissolved solute for a given
amount of solvent at a specific temperature and pressure.
Supersaturated solution:
• Contains more dissolved solute than a saturated solution at the same
temperature.
• To make a supersaturated solution, a saturated solution is formed at
a high temperature and then cooled slowly. The slow cooling allows
the excess solute to remain dissolved in solution at the lower
temperature
• Are unstable. If a tiny amount of solute, called a seed crystal, is
added to a supersaturated solution, the excess solute precipitates
quickly,

19. SOLUBILITY GRAPH
 Determine the
solubility of
KClO3 at 70º C
 Determine if the
solution of 50g of
NaCl in 100g of
water at 80ºC is
unsaturate,
saturate or
supersaturate.

21. SOLUTION CONCENTRATION
 A measure of how much solute is dissolved in a
specific amount of solvent or solution.
• Concentrated : contains a
large amount of solute.
• Dilute: contains a small
amount of solute.
Qualitative:
• Percent by mass
• Percent by volume
• Molarity
Quantitative:

22. QUANTITATIVE DESCRIPTIONS
 These descriptions express concentration as a ratio
of measured amounts of solute and solvent or
solution.

23. PERCENT BY MASS
 Is the ratio of the solute’s mass to the solution’s
mass expressed as a percent.
 The mass of the solution equals the sum of the
masses of the solute and the solvent.

25. PERCENT BY VOLUME
 Usually describes solutions in which both solute
and solvent are liquids; is the ratio of the volume of
the solute to the volume of the solution, expressed
as a percent.
 The volume of the solution is the sum of the
volumes of the solute and the solvent.

27. % MASS-VOLUME
 Calculate the percent by mass/volume of a
prepared solution dissolving 30g of ethanol in water
to fill up 100ml with distilled water.

28. MOLARITY
 Is the number of moles of solute dissolved per liter
of solution. Molarity is also known as molar
concentration, and the unit M is read as molar.
 A liter of solution containing 1 mol of solute is a 1M
solution

30. DILUTING MOLAR SOLUTIONS