The mole and the Avogadro constant — Paper 2 · IGCSE Sciences - Co-ordinated (9-1) 0973

17 The concentration of a sample of dilute sulfuric acid, H2SO4, is 0.01 mol / dm3. What is the mass of sulfuric acid in 1 dm3 of the sample? A 0.49 g B 4.9 g C 0.98 g D 9.8 g

1 marks

Answer: C

This question in 0973/22 May/June 2019

17 1 g of hydrogen contains 6 × 1023 atoms. The relative atomic mass of helium is 4. How many atoms does 1 g of helium contain? A 1.5 × 1023 B 2.4 × 1024 C 6 × 1023 D 2.4 × 1023

1 marks

Answer: A

This question in 0973/21 Oct/Nov 2019

16 What is the volume of 0.35 mol of hydrogen gas at room temperature and pressure? A 2.1 dm3 B 4.2 dm3 C 8.4 dm3 D 16.8 dm3

1 marks

Answer: C

This question in 0973/21 May/June 2020

16 The equation for the complete combustion of methane is shown. CH4 + 2O2  CO2 + 2H2O What is the mass of oxygen that is required for the complete combustion of 16 g of methane? A 8 g B 16 g C 32 g D 64 g

1 marks

Answer: D

This question in 0973/21 Oct/Nov 2020

15 Carbon dioxide is produced in a reaction. It is collected in a gas syringe. The readings on the gas syringe are shown. reading / cm3 initial 7 final 43 What is the mass of carbon dioxide gas produced? A 0.0015 g B 0.0018 g C 0.0660 g D 0.0788 g

1 marks

Answer: C

This question in 0973/21 Oct/Nov 2021

17 When magnesium carbonate reacts with dilute hydrochloric acid, carbon dioxide gas is released. The equation for this reaction is shown. MgCO3 + 2HCl  MgCl 2 + CO2 + H2O Which volume of carbon dioxide, collected at room temperature and pressure, is released when 4.2 g of magnesium carbonate reacts with excess dilute hydrochloric acid? A 1.2 dm3 B 2.4 dm3 C 4.8 dm3 D 12 dm3

1 marks

Answer: A

This question in 0973/21 Oct/Nov 2023

18 The equation for the combustion of magnesium is shown. 2Mg + O2  2MgO What is the mass of magnesium oxide formed from 12 g of magnesium? A 20 g B 24 g C 40 g D 80 g

1 marks

Answer: A

This question in 0973/21 May/June 2024

16 The equation for the reaction of sodium with water is shown. 2Na(s) + 2H2O(l)  2NaOH(aq) + H2(g) Which mass of sodium produces 30 cm3 of hydrogen? A 0.0288 g B 0.0575 g C 28.8 g D 57.5 g

1 marks

Answer: B

This question in 0973/22 May/June 2024

20 Which quantities, when measured at room temperature and pressure, contain one mole of oxygen molecules? 1 16 g of oxygen molecules 2 12 dm3 of oxygen molecules 3 the Avogadro constant number of oxygen molecules 4 24 dm3 of oxygen molecules A 1 and 2 B 1 and 4 C 2 and 3 D 3 and 4

1 marks

Answer: D

This question in 0973/21 May/June 2025

15 Ammonia decomposes when heated in a sealed container in the presence of an iron catalyst. The equation for the reaction is shown. 2NH3(g)  N2(g) + 3H2(g) 40.0 dm3 of ammonia is heated. After several hours, 21.0 dm3 of hydrogen is present. The volumes are measured at r.t.p. What is the percentage of unreacted ammonia? A 35.0% B 47.5% C 52.5% D 65.0%

1 marks

Answer: D

This question in 0973/22 May/June 2025