Metals below carbon in the reactivity series
3 marks · NormalA sample of iron(III) oxide, Fe2O3, weighing 8.0 g is to be reduced by carbon monoxide according to the balanced equation:
Calculate the maximum mass of iron that can be obtained from the sample. (Relative atomic masses: Fe = 56, O = 16)
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5.6 g (±0.1)
Must show: working showing calculation of moles of Fe2O3, mole ratio used from equation, final mass of Fe
Common mistakes: wrong molar mass calculation; using wrong mole ratio
Show mark scheme and worked solution
Marking points
M1 · 1 mark · Correctly calculates moles of Fe2O3 using molar mass (160 g/mol).
M2 · 1 mark · Uses correct stoichiometric ratio (2 mol Fe produced per 1 mol Fe2O3). (follow-through)
A1 · 1 mark · Calculates final mass of Fe (5.6 g). (follow-through)
Worked solution
1. Calculate moles of Fe2O3:
2. Ratio of Fe produced: 1 mol Fe2O3 gives 2 mol Fe.
3. Calculate mass of Fe: