Waste solutions from a copper-plating factory contain copper sulfate. The copper can be recovered by adding scrap zinc.
Zn(s)+CuSO4(aq)→ZnSO4(aq)+Cu(s)\mathrm{Zn(s)} + \mathrm{CuSO_{4}(aq)} \rightarrow \mathrm{ZnSO_{4}(aq)} + \mathrm{Cu(s)}Zn(s)+CuSO4(aq)→ZnSO4(aq)+Cu(s)
Write the ionic equation for this reaction, including state symbols.
Explain why the sulfate ions do not appear in the ionic equation.
Write the two half equations for the changes that happen to the zinc atoms and to the copper ions.
Explain which species is oxidised in this reaction.
Silver can be recovered from waste silver nitrate solution by adding copper. Copper(II) ions, Cu2+\mathrm{Cu^{2+}}Cu2+, and silver atoms form. Write the balanced ionic equation for this reaction.
The factory recovers 3.81 kg of copper from one batch of waste solution. Calculate the minimum mass of zinc, in kg, that must be added. Relative atomic masses: Cu = 63.5, Zn = 65
230 exam-style questions on Edexcel GCSE Chemistry 1.1 Formulae, equations and hazards, covering 1.1.1 Formulae, word and balanced equations, 1.1.2 Balanced ionic equations, and 1.1.3 Hazard symbols and risk in practical work. Each one has a worked solution and a mark scheme showing where the marks go.