T1 BAB 5

The Air Around Us 1

The table shows the percentage of three gases in inhaled and exhaled air. Gas Nitrogen Oxygen Carbon dioxide

Percentage of gas Inhaled air Exhaled air 78 78 21 16 0.03 4

The percentage of oxygen gas decreases because it A B C D

is trapped in the heart is used in respiration is lost through transpiration flows through the whole body PMR 2005

2

Which comparison between combustion and respiration is correct? A B C D

Combustion Uses oxygen Produces oxygen Occurs outside the living cell Occurs in dark condition only

Respiration Produces oxygen Does not produce energy Occurs inside the living cell Occurs in bright and dark conditions PMR 2005

3

Diagram 2 shows an experiment to investigate the percentage of oxygen in air.

Gas jar

Water

Diagram 2 The following are steps taken during the experiment. P - Place a lighted candle in a gas jar Q - Observe the level of water rise in the gas jar as the flames goes out R - Mark the space above the water level in the gas jar into five equal parts

Which of the following sequences is correct? A B C D

R R Q Q

P Q R P

Q P P R PMR 2006

4

What are the products of combustion of a candle? A B C D

Nitrogen and oxygen Water vapour and oxygen Nitrogen and carbon dioxide Water vapour and carbon dioxide PMR 2007

5

Diagram 3 shows a student blowing up a balloon.

Diagram 3 Why does the balloon become bigger?

A Air occupies space B Air expand C Air has mass D

Air is light PMR 2008

6

Which of the following are the correct matches between the gas used and the process related to it? I II III IV

A B C

I and II I and IV II and III

D

III and IV

Gas used Oxygen Carbon dioxide Oxygen Carbon dioxide

Process Respiration Combustion Transpiration Photosynthesis

PMR 2008

7

Which step is implemented to prevent and control air pollution? A B C D

Used leaded fuel Practice car-pooling system Smoke in public places Practice open burning PMR 2008

8

Diagram 4 shows the apparatus set-up to investigate the products of combustion.

Diagram 4 The kerosene is lit and a liquid is collected in test tube P. What will happen to the blue cobalt chloride paper and the lime water?

A B C D

Blue cobalt chloride paper Turns pink Remains blue Remains blue

Lime water Turns cloudy Remains clear Turns cloudy Remains clear PMR 2008

1

(a) Diagram 1 shows the composition of air.

P: 21%

Q: Inert gases

R:

78%

Diagram 1 (i)

On Diagram 1, label gases P,Q and R using the following words: Carbon dioxide

Oxygen

Nitrogen (3 marks)

(i)

State the percentage of carbon dioxide in air. ________________________________________________________ (1 mark)

(b) Draw lines to match oxygen with its properties. Properties

Oxygen

•

•

Slightly soluble in water

•

Very soluble in sodium hydroxide solution

•

Ignites a glowing wooden splinter

•

Changes a moist blue litmus paper to red (2 marks) PMR 2008

The Air Around Us

Paper 1 1. B 2. C 3. A 4. D 5. A 6. B 7. B 8. A Paper 2 (a) (i) P – Oxygen Q - Carbon dioxide R – Nitrogen (ii) 0.03% (iii) Slightly soluble in water Ignites a glowing wooden splinter