Calculating Reacting Masses Using Moles
Guided example:
C(s) + O2(g)  CO2(g)
1 – Calculate the number of moles of carbon in 6 g.
2 – From the equation work out how many moles of CO2 this would make.
3 – Calculate the mass of this many moles of CO2.
Another example:
How much Fe is produced from 1 kg of Fe2O3 in the blast furnace?
Fe2O3(s) + 3CO(g)  2Fe(s) + 3CO2(g)
1 – Calculate the number of moles of Fe2O3 in 1 kg.
2 – From the equation work out how many moles of Fe this would make.
3 – Calculate the mass of this many moles of Fe.
Use the above method to complete the following calculations (remember to write a balanced
equation first!):
1. What mass of ammonia is produced by the Haber process if:
a)
1kg of nitrogen is added to hydrogen?
b)
1 kg of hydrogen is added to nitrogen?
2. What mass of aluminium hydroxide precipitates when an excess of sodium hydroxide
solution is added to a solution containing 20 g of aluminium nitrate?
3. What mass of calcium oxide is left when 5 kg of calcium carbonate is thermally
decomposed?
4. What mass of oxygen is needed to produce 200 g of magnesium oxide?
5. What mass of anhydrous copper sulphate is produced when 5.0 g of hydrated copper
sulphate, CuSO4·5H2O, is heated?
6. What mass of chlorine would be needed to make 1 kg of titanium(IV) chloride?