Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Chapter
Gases in the Atmosphere
86 practice questions
Topics covered
Practice questions
31–35 of 35 · Easy
Question 31
2 marks · Easy
Answer and see the solution →A student heats 1.2 g of magnesium carbonate (ce{MgCO3}) and all of it decomposes. Calculate the maximum mass of carbon dioxide gas that can be produced. (Relative atomic masses: Mg = 24, C = 12, O = 16)
Question 32
5 marks · Easy
Answer and see the solution →This question is about gases in air and combustion in oxygen.
(a)[2 marks]State the approximate percentage by volume of oxygen and nitrogen in dry air.
(b)[2 marks]Describe the complete combustion of magnesium in oxygen. State the chemical formula of the product formed.
(c)[1 mark]Which property of oxygen explains why elements burn more brightly in oxygen than in air?
Question 33
5 marks · Easy
Answer and see the solution →This question is about experiments to show the amount of oxygen in air, and the combustion of elements in oxygen.
(a)[2 marks]Describe how an experiment using wet iron filings can be used to find the approximate percentage of oxygen in air. State one precaution needed for an accurate result.
(b)[1 mark]A student burns magnesium ribbon in pure oxygen. State the chemical name and appearance of the solid product formed.
(c)[2 marks]Explain why elements burn more brightly in pure oxygen than in air.
Question 34
5 marks · Easy
Answer and see the solution →Nitrogen and oxygen are the main gases in air. Burning elements in oxygen produces different products and different observations.
(a)[2 marks]State the percentage by volume of nitrogen and oxygen in dry air.
(b)[2 marks]Describe an experiment using copper to determine the percentage of oxygen in air, including what you would observe during the experiment.
(c)[1 mark]Hydrogen burns in oxygen to form a product. Name the product and describe what you would see when hydrogen burns in oxygen.
Question 35
5 marks · Easy
Answer and see the solution →A student uses an experiment involving heated copper to determine the percentage of oxygen in a sample of air. She then compares the combustion of magnesium in air and in pure oxygen.
(a)The apparatus originally contains 80 cm³ of air. After the reaction with copper is complete and the apparatus has cooled, the remaining gas volume is 63 cm³.
(i)[1 mark]Calculate the volume of oxygen removed from the air.
(ii)[1 mark]Calculate the percentage of oxygen in the air sample. Show your working.
(b)[1 mark]Describe why it is important to use excess copper in this experiment.
(c)[2 marks]Magnesium burns in air to produce a white powder. Explain how the combustion of magnesium differs when it burns in pure oxygen instead of in air.