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3.2 Use of amount of substance in relation to masses of pure substances

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Question 7
H

Zinc carbonate decomposes when heated.

ZnCO3→ZnO+CO2\text{ZnCO}_3 \rightarrow \text{ZnO} + \text{CO}_2ZnCO3​→ZnO+CO2​

Relative formula masses (MrM_rMr​): ZnCO3=125\text{ZnCO}_3 = 125ZnCO3​=125, ZnO=81\text{ZnO} = 81ZnO=81

What mass of zinc oxide is produced when 25 g of zinc carbonate decomposes completely?

[1]
A

16.2 g16.2\ \text{g}16.2 g

B

25 g25\ \text{g}25 g

C

32.4 g32.4\ \text{g}32.4 g

D

81 g81\ \text{g}81 g

Markscheme

3.2 Use of amount of substance in relation to masses of pure substances Questions

  1. GCSE
  2. /Chemistry
  3. /3.2 Use of amount of substance in relation to masses of pure substances

40 exam-style questions on AQA GCSE Chemistry 3.2 Use of amount of substance in relation to masses of pure substances, covering 3.2.1 Moles, 3.2.2 Amounts of substances in equations, 3.2.3 Using moles to balance equations, 3.2.4 Limiting reactants, 3.2.5a Concentration of solutions, and 3.2.5b Relating mass, volume and concentration. Each one has a worked solution and a mark scheme showing where the marks go.

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