Chemistry C1 7.5 Gases in the atmosphere. 0.0 / 5 ? ChemistryThe earth and its atmosphereGCSEAQA Created by: Atlanta and JacobCreated on: 11-09-16 16:11 What happened to most of the carbon dioxide in the early atmosphere? It become locked up lim sedimentary rocks. 1 of 16 What is the atmosphere mainly made of and in what proportion? About four-fifths (almost 80%) is nitrogen and about one-fifth (just over 20%) is oxygen. 2 of 16 How can the main gases in the air be separated? By fractional distillation. 3 of 16 What can the gases within the atmosphere be used in? Industry as raw materials. 4 of 16 What took up much of the carbon dioxide in the Earth's early atmosphere? Plants. Animals ate the plants and much of the carbon ended up in plant and animal remains as sedimentary rocks and fossil fuels. 5 of 16 What was limestone formed from? The shells and skeletons of marine organisms. 6 of 16 What do fossil fuels contain? Carbon and hydrogen from plants and animals. 7 of 16 Apart from plants, how else was carbon dioxide removed from the atmosphere? Carbon dioxide dissolves in the oceans. 8 of 16 What may have happened to some of the carbon dioxide dissolved in the oceans? Some probably formed insoluble carbonate compounds that were deposited on the seabed and became sedimentary rocks. 9 of 16 What happened to the atmosphere 200 million years ago? The proportions of gases in the atmosphere had stabilised and were much the same as today. 10 of 16 Apart from nitrogen and oxygen, what other gases are there in the atmosphere? Carbon dioxide, water vapour and noble gases make up about 1% of the atmosphere. 11 of 16 How can fractional distillation be used to separate the gases in the air? Because they have different boiling points. 12 of 16 In what ways did carbon dioxide become 'locked up'? In fossil fuels, in sedimentary rocks (including limestone). 13 of 16 What are the approximate percentages of nitrogen and oxygen in the air? 78% nitrogen (almost 80%), 21% oxygen (just over 20%). 14 of 16 Why can the gases air be separated by fractional distillation? It is a mixture of different substances that have different boiling points. 15 of 16 **YOU SHOULD BE ABLE TO EXPLAIN THE FRACTIONAL DISTILLATION OF LIQUID AIR, GIVEN THE BOILING POINTS OF NITROGEN AND OXYGEN** **LOOK UP FRACTIONAL DISTILLATION OF LIQUID AIR** 16 of 16
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