1Calcium carbonate breaks down on heating to produce calcium oxide and carbon dioxide gas. CaCO3 → CaO + CO2
A student heats 15 g of calcium carbonate strongly in a crucible.
Relative atomic masses (Ar): Ca = 40, C = 12, O = 16.
aCalculate the number of moles in 15 g of calcium carbonate. 0.15(2 marks)
bUse your answer to part a to determine the number of moles of calcium oxide that will be produced.(1 mark)
cCalculate the mass of calcium oxide produced by this reaction.(2 marks)

2A student is preparing a sample of sodium nitrate, NaNO3.
She mixes 17 g of sodium oxide with an excess of nitric acid. The equation for the reaction is:
Na2O + 2HNO3 → 2NaNO3 + H2O
Relative atomic masses (Ar): Na = 23, O = 16, N = 14, H = 1.
aCalculate the number of moles in 17 g of sodium oxide.(2 marks)
bCalculate the maximum mass of sodium nitrate that can be produced in this reaction.(3 marks)

3Aluminium and iron oxide (Fe2O3) react together to produce aluminium oxide (Al2O3). The equation for the reaction is:
2Al + Fe2O3 → Al2O3 + 2Fe
Calculate the mass of iron that is produced by reacting 20 g of iron oxide with an excess of aluminium.
Relative atomic masses (Ar): Al = 27, O = 16, Fe = 56.(4 marks)