SCIENCE FORM 1 CHAP 7 (7.1)

CHAPTER 7:

Air

7.1 COMPOSITION OF AIR

Air is a mixture of nitrogen, oxygen, carbon dioxide and inert gas

THE COMPOSITION OF AVERAGE PERCENTAGE
AIR OF ITS COMPONENTS BY

Nitrogen VOLUME
Oxygen
Carbon Dioxide 78 %
Inert gases and others
21 %
0.03 %
0.97 %

DRAW!!! Oxygen makes up 1
5
Nitrogen is
an inactive (one-fifth) of the air.

gas Very important for

Air also contains respiration
water vapour,
microorganism Carbon dioxide
important for
and dust photosynthesis

DRAW!!! EXPERIMENT:

TO DETERMINE THE PERCENTAGE OF OXYGEN IN THE AIR

5
4
3
2
1

Water level increase to the level marked 1.
It shows that composition of oxygen is 1/5 or
21% of the air.

EXPERIMENT:
TO Prove that air contains WATER VAPOUR

BLUE CHANGE TO
PINK

THE WATER IS
PRESENT

EXPERIMENT:
TO Prove that air contains DUST

THE DUST STICK ON
THE SELOTAPE

THE DUST IS
PRESENT

EXPERIMENT:
TO Prove that air contains MICROORGANISM

THE MICROORGANISM
GROW ON THE JELLY

THE MICROORGANISM
IS PRESENT

THE Oxygen

IMPORTANCE
OF GAS Carbon dioxide

nitrogen Inert gas

oxygen

Carbon dioxide

Water
vapour

- respiration

oxygen

• Combustion of rocket engine

• Welding and steel cutting • Preparation
of various
compound

Carbon dioxide

• Fire
extinguisher

• Photosynthesis • Production of
carbonated
drink

Nitrogen Cooling agent

Nitrogen cycle Nitric acid and
ammonia

Inert gas Neon gas in advertising
light

Helium in hot air Argon gas in
balloon light bulb

CARBON DRAW!!!
CYCLE

ABSORB CARBON DIOXIDE

- Photosynthesis

RELEASE CARBON DIOXIDE

- Respiration
- Decomposition
- Combustion

Maintains the content of CO2

DRAW!!! OXYGEN

Very important !!!!! CYCLE

NEED OXYGEN

- Respiration
- Combustion
- Rusting
- Decomposition

RELEASE OXYGEN

- Photosynthesis