1. How many grams of magnesium oxide would be produced by reacting completely 4.0 g of magnesium with oxygen?
2Mg + O2 à 2MgO
2. Oxygen can be converted into ozone (O3) by passing an elecrical discharge through it. Calculate the number of ozone molecules that would be formed if 16g of oxygen were completely converted into ozone.
3O2 à 2O3
3. Ammonia reduces copper(II) oxide to copper. The other products of the reaction are water and nitrogen.
2NH3 + 3CuO à 3Cu + H2O + N2
Calculate the mass of copper produced and the mass of ammonia consumed when 56.4g of copper(II) oxide are reduced in this way.
4. What mass of aluminium will be needed to react with 10 g of CuO, and what mass of Al2O3 will be produced?
3CuO + 2Al à Al2O3 + 3Cu
5. In a reaction magnesium carbonate powder is used to neutralise 250 cm3 of 2 mol l-1 dilute hydrochloric acid. Calculate the mass of magnesium carbonate required to neutralise the dilute hydrochloric acid.
MgCO3 + 2HCl à MgCl2 + H2O + CO2
6. In a reaction sodium carbonate powder is used to neutralise 200 cm3 of 2 mol l-1 dilute sulphuric acid. Calculate the mass of sodium carbonate required to neutralise the dilute sulphuric acid.
Na2CO3 + H2SO4 à Na2SO4 + H2O +CO2
7. 20 cm3 of a solution of NaOH is exactly neutralised by 25 cm3 of a solution of HCl of concentration 0.5 mol l–1.
HCl + NaOH → NaCl + H2O
Calculate the concentration of the NaOH solution in mol l –1.
8. 100 cm3 of a solution of KOH is exactly neutralised by 150 cm3 of a solution of H2SO4 of concentration 0.25 mol l–1.
H2SO4 + 2KOH → K2SO4 + 2H2O
Calculate the concentration of the KOH solution in mol l –1.
9. 50 cm3 of a solution of HCl is exactly neutralised by 20 cm3 of a solution of Ca(OH)2 of concentration 2.0 mol l–1.
2HCl + Ca(OH)2 → CaCl2 + 2H2O
Calculate the concentration of the HCl solution in mol l –1.
10. 2.5 l of a solution of NaOH is exactly neutralised by 1.5 l of a solution of HCl of concentration 1.0 mol l–1.
HCl + NaOH → NaCl + H2O
Calculate the concentration of the NaOH solution in mol l –1.
