water & solution science form 2
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WATER & SOLUTION
Facts: 2/3 of earth’s surface is covered with water.
SCIENCE FORM 2
By:
Nur Hidayah Taib
SMK Lembah Bidong ‘12
Physical characteristics of water
PURE WATER IS COLOURLESS, ODOURLESS, TASTELESS
LIQUID
STATE OF WATER
Physical characteristics of water
Melting Boiling
CondensationFreezing
Sublimation
FREEZING AND BOILING POINT OF WATERFreezing point: the temperature at which water freeze to form ice.
Physical characteristics of water
Boiling point: temperature when water boils to produce steam.
Heat is absorbed
Heat is released
KINETIC THEORY
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.
The composition of water
OH H
Chemical formula: H2O
ELECTROLYSIS OF WATER• Electrolysis is a process of to break down a
compound into simpler substances.
A
H2O2
Water + dilute sulphuric acid
anodecathode
EVAPORATION OF WATER
EVAPORATION BOILING
SIMILARITIES Liquid gas Absorps heat
DIFFERENCES Occurs at any temperature Occurs only at boiling point
Occurs only on the exposed surface of a liquid
Occurs throughout the liquid
No bubbles are formed Bubbles formed throughout the liquid
Absorbs heat from the surroundings when water turns into gas
Requires heat supplied by a source such as a lighted bunsen burner
SOLUTION AND SOLUBILITY
SOLUTE
SOLVENT
Substances that dissolves
Substances that dissolve the solute
Concentrated solutionIt refers to a solution in which much of the water has been removed.
Dilute solutionto make (a liquid) thinner or weaker by the addition of water or the like.
Saturated solutionsolution in which the maximum amount of solvent has been dissolved. Any more solute added will sit as crystals on the bottom of the container.
SUSPENSIONSolution 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 easily separated
Contains substances that easily be separated
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.
FACTORS THAT AFFECT THE
SOLUBILITY OF SOLUTE IN WATER
Stirring
Volume of solvent
Temperature
Size of solute
WATER AS A UNIVERSAL
SOLVENT
Useful solution e.g: eye drops,
antiseptic lotion
Daily activities
Supplies CO2 to aquatic plants
Dissolve substance e.g: medicinal drugs,
poisons
Supply dissolved oxygen to
marine animals
Provide plants with nutrients
Transport dissolved nutrients and waste
products to various part of the body of living
things
Substances that do not dissolve in water may be soluble in ORGANIC
SOLVENTS
ORGANIC SOLVENTS
USES
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
ACIDS AND ALKALIS
ACIDSTaste: 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.
ALKALISTaste: 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
NEUTRAL
A chemical reaction in which an acid and alkali react to produce salt and water
ACID + ALKALI SALT + WATER
e.g: NaOH + HCl NaCl + H2O
NEUTRALISATION
APPLICATIONS OF NEUTRALISATION
Shampoos Hair conditioner
bicarbonate powder slaked lime
toothpaste
METHODS OF WATER
PURIFICATION
SEDIMENTATION FILTRATION CHLORINATION
OZONE
BOILING
DISTILLATION
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.
UV LIGHT
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.
WATER PURIFICATION
WATER POLLUTION