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Question 1
Air is a mixture of gases. The pie chart shows the percentages, by volume, of the main gases in air from Earth's atmosphere today. |
a) | Complete the chart by adding the names of these three gases.
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b) | The percentages of carbon dioxide and oxygen have changed from Earth’s early atmosphere to Earth’s atmosphere today. Explain the processes that led to these changes.
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Question 2
The Earth's early atmosphere was formed billions of years ago. The bar graph below shows the composition of the Earth’s atmosphere as it was billions of years ago, and as it is today. |
a) | Where is it likely that the carbon dioxide in the early atmosphere came from?
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b) | State two differences between the atmosphere today and the atmosphere of billions of years ago.
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c) | Describe the processes which have brought about the changes in the proportions of gases in the air.
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d) | Why are scientists not certain about the percentage of each gas in the Earth’s early atmosphere?
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Question 3
The graph below shows how the concentration of carbon dioxide in the air varied from the year 1000 to the year 2000. |
a) | Describe the changes in the concentration of carbon dioxide in the air from the year 1000 to the year 2000.
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b) | Suggest why the concentration of carbon dioxide in the air has changed from the year 1800 to the year 2000.
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c) | Explain why we should be concerned about the change in percentage of carbon dioxide in the Earth’s atmosphere over the last 100 years.
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Question 4
About 3 billion years ago, carbon dioxide was one of the main gases in the Earth’s atmosphere. About 500 million years ago, plants started to grow on most of the land. When the plants died, they slowly decayed to form coal. |
a) | Describe and explain how the composition of the Earth’s atmosphere was changed by the formation of coal.
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b) | How does burning coal affect the amount of carbon dioxide in the Earth’s atmosphere today? Explain your answer.
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c) | The Earth’s average surface temperature decreased over time. At what temperature would oceans have started to form?
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Question 5
Scientists believe that the Earth formed as a molten ball of rock and minerals which cooled slowly. Scientists suggested that the surface of the Earth was covered by volcanoes that released gases that formed the Earth’s early atmosphere. The pie charts show the approximate percentages of gases in the Earth’s early atmosphere and in the Earth’s atmosphere today. |
a) | Describe how volcanoes caused the oceans to be formed.
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b) | Give two reasons why the percentage of carbon dioxide in the Earth’s atmosphere has decreased.
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c) | About 60 million years ago a large meteorite hit the Earth. This meteorite heated limestone in the Earth’s crust causing the release of large amounts of carbon dioxide. Explain how carbon dioxide is released from limestone.
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d) | Suggest one reason why there was no liquid water on the Earth’s surface billions of years ago.
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Question 6
The Earth has a layered structure and is surrounded by an atmosphere. The data in the table shows the percentages of gases in the Earth’s atmosphere. |
a) | Plot the data in the table on the grid below.
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b) | Which one of the gases in the table is a noble gas?
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c) | The percentage of carbon dioxide in the Earth’s early atmosphere was 95.00%. The percentage of carbon dioxide is 0.04% in the Earth’s atmosphere today. Calculate the decrease in the percentage of carbon dioxide in the Earth’s atmosphere.
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d) | Give two reasons for this decrease.
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Question 7
The image below shows representations of the early Earth and the Earth today. |
a) | How long ago was the Earth formed? A 46 billion years ago B 4.6 billion years ago C 46 million years ago D 4.6 thousand years ago
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b) | Which process in algae and plants increased the percentage of oxygen in the Earth’s atmosphere?
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c) | Describe and explain how the surface of the early Earth and its atmosphere have changed to form the surface of the Earth and its atmosphere today.
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d) | Describe how carbon dioxide helps to maintain temperatures on Earth.
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Question 8
The figure below shows how the percentages of gases in the Earth’s atmosphere may have changed in the last 4,500 millions of years. |
a) | Explain the change in the percentage of gas: |
a) i) | in the region labelled A.
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a) ii) | in the region labelled B.
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a) iii) | in the region labelled C.
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b) | When did the percentage of nitrogen in the Earth’s atmosphere become constant?
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c) | Most of the percentages of the gases in the graph above are estimated. Why have scientists used estimated values in the figure above?
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Question 9
The pie graph below shows the composition of the atmosphere on the planet Mars. |
a) | Calculate the percentage of carbon dioxide in the atmosphere on Mars.
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b) | The atmosphere on Earth is very different from that on Mars. Give three ways in which the Earth’s atmosphere is different from the atmosphere on Mars.
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c) | When the Earth was formed its atmosphere is thought to have been similar to the atmosphere on Mars. Explain how green plants and other organisms have changed the composition of the Earth’s atmosphere.
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Question 10
Titan is the largest moon of the planet Saturn. The average surface temperature on Titan is -178 °C. The table below shows information about the gases in Titan's atmosphere. |
a) | Why are algae less likely to photosynthesise on Titan than Earth? A Titan’s atmosphere contains too little argon B Titan’s atmosphere contains too little carbon dioxide C Titan’s atmosphere contains too little methane D Titan’s atmosphere contains too little nitrogen
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b) | When it rains on Titan, it rains methane. Use the information above to explain why.
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c) | Titan is warmer than the other moons of Saturn because its atmosphere contains the greenhouse gas methane. How does methane keep Titan warmer than the other moons of Saturn?
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d) | Some scientists think that living organisms could have evolved on Titan. Explain why these organisms could not have evolved in the same way that life is thought to have evolved on Earth.
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