LSC: Air Assignment

1 Which of the following gases makes up around one-fifth of the air?
A) argon C) nitrogen
B) carbon dioxide D) oxygen
2 Which of the following describes photosynthesis?
A) oxygen reacts with starch to produce carbon dioxide and water
B) carbon dioxide and water react to produce starch and oxygen
C) yeast uses sugar to make carbon dioxide and alcohol
D) carbon dioxide turns limewater milky
3 Which of the following reactions uses up carbon dioxide from the air?
A) burning wood C) respiration
B) fermenting yeast D) photosynthesis
4 How much oxygen will there be in a litre of air?
A) 100 cm3

C) 500 cm3
B) 800 cm3

D) 200 cm3

5 You are given two tubes of a colourless gas. Explain how you could find out if the gas
is oxygen or carbon dioxide.
6 Many fuels contain carbon.
a) Name one of the gases that would be produced when fuel burns.
b) Design an experiment to find out whether the methylated spirits in your burner
contains carbon.
7 Some wet rotting leaves were placed in a jam jar. A small open tube of limewater was
also put in the jar and the lid was screwed onto the jar. After a day or two the
limewater looked milky.
a) Explain why the limewater turned milky.
b) Explain what the experiment tells you about what happens when leaves rot.
8 When you unscrew the top of a bottle of fizzy drink, you see bubbles coming up.
Explain how you would try to find out if the bubbles were carbon dioxide. Draw a
picture showing what you would do.
9 Observe – explain
Write a sentence explaining each of these observations. If you do not know the
answer, use your scientific knowledge to suggest one.
a) Rainwater is always slightly acidic.
b) If you cover a fire with sand, it stops burning.
c) Water plant leaves are often covered with bubbles when the sun shines on them. If
the bubbles are collected, they will relight a glowing splint.
d) The equipment in sketch (a) was set up. A week later the water levels were as
shown in sketch (b).

e) Fires burn more strongly

e) Fires burn more strongly when a wind is blowing.