M. RahmanC1 TOPIC 1

1) What is the approximate percentage of oxygen in Earth’s modern day atmosphere?.

Answer

21 %

M. RahmanC1 TOPIC 1

2) Which gas has the largest percentage in Earth’s modern day atmosphere?

Answer

Nitrogen

M. RahmanC1 TOPIC 1

3) Which gas made up the majority of the Earth’s early atmosphere?

AnswerCarbon dioxide

M. RahmanC1 TOPIC 1

4) Where is much of the gas that once made up the Earth’s early atmosphere now located?

Answer.

It dissolved in oceans and was then taken up by marine organisms.

M. RahmanC1 TOPIC 1

5) What is the approximate percentage of carbon dioxide currently found in the atmosphere?

Answer.

0.04 %

M. RahmanC1 TOPIC 1

6) Give three ways humans have contributed to the amount of CO2

in the atmosphere

Answera) deforestationb) burning fossil fuelsc) farming

M. RahmanC1 TOPIC 1

7) Which of the following activities is not a human activity that causes small changes to the atmosphere over time?

a) deforestationb) burning fossil fuelsc) volcanoes eruptingd) farming

AnswerC) volcanoes erupting

M. RahmanC1 TOPIC 1

8) Which process was responsible for increasing the amount of oxygen in the atmosphere over time?

Answer

photosynthesis

M. RahmanC1 TOPIC 1

9) Which gas do plants take out of the atmosphere?

carbon dioxide

M. RahmanC1 TOPIC 1

10) Which of the following gases are released by volcanoes?

a) oxygen and nitrogenb) carbon dioxide and hydrogenc) oxygen onlyd) carbon dioxide and steam

Answer

d) carbon dioxide and steam

M. RahmanC1 TOPIC 1

11) Which of the following gases could be released when fossil fuels are burned?

a) carbon dioxide and carbon monoxideb) carbon dioxide and oxygenc) ammonia and nitrogend) nitrogen and oxygen

Answer

a) carbon dioxide and carbon monoxide

M. RahmanC1 TOPIC 1

12) How where oceans formed (3)

Answer1) Water vapour released from volcanoes2)Water vapour condensed as the earth cooled.3) Rain falls to fill up the hollows in the crust.

M. RahmanC1 TOPIC 1

13) Describe why burning fossil is harmful to the earth and its environment (2).

Answer

• Increases amount of CO2 in the atmosphere,; • carbon dioxide is a green house gas, which causes global

warming;• greenhouse gases prevent heat from leaving the earths

atmosphere; • Trapped heat causes the earth temperature to rise.

.

M. RahmanC1 TOPIC 1

14) Billions of years ago, which gas was in the greatest amount?

AnswerCarbon dioxide

M. RahmanC1 TOPIC 1

15) Give the origins of one piece of evidence that scientist have collected to explain the composition of the earths atmosphereAnswer

• Antarctic ice cores-difference layers contain different amount of each gas. Each layer represents a different time.

or• Oxygen locked in rocks.

M. RahmanC1 TOPIC 1

16) In todays atmosphere, which gas is present that was either in very small amounts or not at all

Answer

Oxygen

M. RahmanC1 TOPIC 1

17) Explain how the levels of oxygen has changed over billions of years (2).

AnswerPrimitive green plants evolved using carbon dioxide (1) and released oxygen by photosynthesis (1).

M. RahmanC1 TOPIC 1

18) Describe how carbon gets locked into sedimentary rocks (2).

Answer

Carbon dioxide dissolved in sea water reacts with other chemicals to form calcium carbonate and calcium hydrogen carbonate (1). The shells of dead sea creatures accumulate and are transformed into sedimentary rocks (1).

M. RahmanC1 TOPIC 1

19) Describe how the levels of carbon dioxide in the atmosphere in the earths early atmosphere was reduced(2).

AnswerBy photosynthesis (1) and by dissolving in the oceans (1)

.

M. RahmanC1 TOPIC 1

20) Name three ways humans are changing the atmosphere.

Answer1) Burning of fossil fuels2) deforestation3) livestock farming

M. RahmanC1 TOPIC 1

21)

Answer• Iron reacts with oxygen to from iron oxide.• Reaction uses up oxygen and total amount of air

reduces.• The water rises inside the tube to• fill up the gap

100 mm 79 mmiron

1) Explain how the above experiment could be used to determine the amount of oxygen in the atmosphere (4 marks)

M. RahmanC1 TOPIC 1

20)

Answer300 x 0.21=63 mm (1) 300-63= 237mm (2)

22)300 mm ? mm

iron

1) If the atmosphere contains 21 % oxygen, what will the final reading be.

Show your working out. (3 marks)

M. RahmanC1 TOPIC 1

20)

Answer750-592 =158 (1) 158/750= 0.21 (1)0.21 x 100 = 21 %

23)750 mm 592 mm

iron

1) Show that the percentage of oxygen in the atmosphere is 21 %.

M. RahmanC1 TOPIC 1

24)

Answer• Copper reacts with oxygen to from copper oxide.• Reaction uses up oxygen and total amount of air reduces.• The gap between the syringes should reduce.• Compare reading before heating with after heating.

1) Explain how the above experiment could be used to determine the amount of oxygen in the atmosphere (4 marks)

M. RahmanC1 TOPIC 1

25)

AnswerIron + Oxygen ---- Iron Oxide

Iron reacts with oxygen to produce iron oxide. Write the word equations.