4. Physical characteristics of water
FREEZING AND BOILING POINT OF WATER
Freezing point: the temperature at Boiling point: temperature when water
which water freeze to form ice. boils to produce steam.
Heat is released
KINETIC
THEORY
Heat is absorbed
5. The effect of impurities on the physical
characteristics of water.
• Freezing point and melting point of water are
same.
• Impurities increase the boiling point of water.
• Impurities lower the freezing point of water.
7. ELECTROLYSIS OF WATER
• Electrolysis is a process of to break down a
compound into simpler substances.
O2
H2 Water + dilute sulphuric acid
cathode anode
A
9. EVAPORATION BOILING
SIMILARITIES Liquid gas
Absorps heat
DIFFERENCES Occurs at any temperature Occurs only at boiling point
Occurs only on the exposed Occurs throughout the liquid
surface of a liquid
No bubbles are formed Bubbles formed throughout the
liquid
Absorbs heat from the Requires heat supplied by a source
surroundings when water such as a lighted bunsen burner
turns into gas
10. SOLUTION AND SOLUBILITY
SOLUTE Substances that
dissolves
SOLVENT Substances that
dissolve the solute
11. Concentrated solution
It refers to a solution in which much of the water has
been removed.
Dilute solution
to make (a liquid) thinner or weaker by the addition of
water or the like.
12. Saturated solution
solution in which the maximum amount of solvent has been
dissolved. Any more solute added will sit as crystals on the bottom
of the container.
13. SUSPENSION
Solution suspension
homogeneous Non-homogeneous
Clear/transparent Cloudy/translucent
Contains one or more soluble substances Contains one ore more insoluble
subtances
Contains substances that cannot be Contains substances that easily be
easily separated separated
14. SOLUBILITY
The maximum amount of a solute which can dissolve in a
given amount of solvent at a fixed temperature.
THE RATE OF DISSOLVING
Time taken for the dissolving process, from the time the solute is
added to the solvent until it has completely dissolved.
15. Stirring
Size of FACTORS THAT
AFFECT THE Volume of
SOLUBILITY OF solvent
solute SOLUTE IN WATER
Temperature
16.
17. Substances that do not dissolve in water
may be soluble in ORGANIC SOLVENTS
ORGANIC USES
SOLVENTS
CHLOROFORM •Stick plastics letter & numbers on the number plats of vehicle
BENZENE •To stick piece of rubber on a punctured tyre
ALCOHOL •Prepare shellac
•Dissolve iodine to make antiseptic
AMYL ACETATE •Remove lipstick stain
TURPENTINE •Remove paint from the floor
LIME JUICE •Remove rust
19. ACIDS
Taste: Sour.
Touch: Like water.
Tested with litmus paper: Turn blue litmus red.
pH value: From 0 to less than 7.
Reaction with metals: Form hydrogen and a salt.
Reaction with carbonates: Form a salt, water and carbon dioxide.
Reaction with ammonium compounds: No reaction.
NEUTRAL
ALKALIS
Taste: Bitter.
Touch: Soapy.
Tested with litmus paper: Turn red litmus blue.
pH value: From above 7 to 14.
Reaction with metals: No reaction.
Reaction with carbonates: No reaction.
Reaction with ammonium compounds: Give off ammonia gas
23. UV LIGHT
•As the water passes through this vessel, microorganisms are exposed to
intense ultraviolet light energy which causes damage to genetic
molecules (i.e. nucleic acids: DNA or RNA) needed for reproductive
functions.
•This damage prevents the microorganism from multiplying or
replicating in a human or animal host.
•Because the microorganism cannot multiply, no infection can occur.
Disinfection of water is achieved when UV light causes microbial
inactivation.
24.
25.
26.
27. WATER PURIFICATION
1. Water from the rivers are channel into the reservoir.
2. In the Aeration Tank bad smells will be aired and removed from the water.
3. Alum and Lime are added into the water in the coagulation tank. Alum will
make particles join together to form larger particles while lime will decrease
the acidity of water.
4. In the mixing tank, alum and lime will be evenly distributed in the water the
water.
5. The water travels into the sedimentation tank so that large particles will
sediment to the bottom.
6. Lighter particles which floats on the water will flow into the filtration
tank, suspended particles will be filtered.
7. Clean water will then be stored at the storage tank. In the storage
tank, chlorine and fluorine will be added in the water.
