FORM 2 CHAPTER 5 WATER AND SOLUTION

CHAPTER 5:

WATER AND SOLUTION

WHAT WILL YOU LEARN IN CHAPTER 5??

 Physical characteristics of water
 Composition of water
 Evaporation of water
 Solution and solubility
 Water purification
 Water supply system
 Water sustainability

5.1 PHYSICAL CHARACTERISTICS OF WATER

Colorless, odorless, tasteless

Has pH value 7

Poor thermal and electrical conductor

Freezing point = 0oC

Boiling point = 100oC

Density = 1g/cm3



CHANGES OF THE STATE OF MATTER CAUSED BY THE
ABSORPTION AND THE RELEASE OF HEAT BASED ON
KINETIC THEORY OF MATTER

Effects of impurities on the physical characteristics of water

<Freezing point 0oC

+ Salt = >Boiling point 100oC

>Density 1g/cm3

COMPOSITION OF WATER

WATER Compound which is made up

of the elements hydrogen
and oxygen

Chemical formula: H2O

Electrolysis can determine the

composition of water

oxygen hydrogen In the electrolysis…

anode cathode Hydrogen gas released at the
cathode.
+ -
Oxygen gas released at the anode.

Volume of hydrogen gas is two times
than volume of oxygen.

So, water is made up of 2 volumes of
hydrogen and one volume of oxygen.

2H+ + O2-  H2O

oxygen hydrogen

anode cathode

+ -

EVAPORATION OF WATER

A process in which liquid changes
to gas at any temperature

below the liquid’s boiling point



4 FACTORS THAT
AFFECT THE RATE
OF EVAPORATION

Humidity

the higher the humidity, the slower the process of evaporation



Surrounding temperature

the higher the temperature of surrounding, the faster the
process of evaporation



Surface area of the water

the larger the surface area of the water, the faster the process
of evaporation







Air movement

Moving air helps to remove water molecules from the water
surface







APPLICATIONS OF THE
EVAPORATION OF WATER IN
DAILY
LIFE

1. Drying clothes

2. Preservation of agricultural products (fish
cracker, dried shrimps, anchovies, dried chillies)

3. Threating injury
- evaporation of alcohol reduces the pain

4. Cooling down the body
-sweat that evaporate from skin’s surface
will remove heat

WHAT WILL YOU LEARN IN CHAPTER 5??

 Physical characteristics of water
 Composition of water
 Evaporation of water
 Solution and solubility
 Acid and alkali
 Water purification
 Water supply system
 Preservation of water quality

5.2 SOLUTION AND RATE OF SOLUBILITY

Solution Mixture formed when a solute
dissolves in a solvent
Solute substance that dissolve in a liquid
Solvent
liquid that dissolves a substance





DILUTE, CONCENTRATED AND SATURATED SOLUTION

DIFFERENT CONCENTRATION







SOLUBILITY??

Maximum amount of the solute that can
dissolve in 100 ml of solvent at a specific
temperature

3 FACTORS AFFECTING THE RATE OF SOLUBILITY

RATE ? How fast

1) Temperature 2) Rate of stirring 3) Size of solute

FACTORS AFFECTING THE RATE OF SOLUBILITY

（1）Temperature  The higher the temperature of
of solvent
solvent, the higher the rate of

solubility.

 High temperature cause the
particles to move fast, hence,
increase the rate of collision
(perlanggaran) between
solvent and solute.

FACTORS AFFECTING THE RATE OF SOLUBILITY

2) Rate of stirring  The higher the rate of stirring,
the higher the rate of solubility.

 Stirring cause the particles to
move fast, hence, increase the
rate of collision (perlanggaran)
between solvent and solute.

FACTORS AFFECTING THE RATE OF SOLUBILITY

3) Size of solute  The smaller the solute, the
higher the rate of solubility.

 The smaller size of solutes have
a bigger surface area for
collision (perlanggaran)
between solvent and solute.

SOLUTION, SUSPENSION, COLLOID







MILK ?

Examples of colloid *Paint

*Milk *Yoghurt *mayonnaise

colloids neither form a clear mixture nor precipitate

EXAMPLE:-