5.1 The composition of air

78%

0.03% 21%

1%R: …………………………….

P: ………………………….

Q: ………………………..

Diagram 1.1

Carbon dioxideoxygen

nitrogen

1) Why air is a mixture?Percentage of components of air varies(not fixed)

5.2 the properties of oxygen and carbon dioxide

State whether the following statements are TRUE or FALSE

a) Oxygen is acidicb) Carbon dioxide is acidicc) Oxygen supports combustiond) Carbon dioxide turns lime water cloudye) A burning splinter is used to test for the

presence of oxygen

FALSE

TRUE

TRUE

TRUE

TRUE

5.3 oxygen is needed for respiration

What is respiration?

Respiration is a process by which our body obtains and uses oxygen to oxidise food for the production of energy. Carbon dioxide and water vapour are released as the by-product

Respiration process :

oxygen glucose energy Carbon dioxide

Water vapour

5.4 oxygen is needed for combustion

• What needed for combustion?

OxygenHeatfuel

The product of combustion

_______ + _______ _______+_____+_____

______+____________+______+_____+____

carbon oxygenCarbon dioxide heat light

hydrocarbon oxygenCarbondioxide

Watervapour heat light