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