WJEC Chemistry for AS Level: Revision Workbook

Q3 Aluminium oxide reacts slowly with acids but when heated with excess sulfuric acid forms a solution of aluminium sulfate. (a) Write an equation for this reaction. [2] ......................................................................................................................................................................................................................................................................................................................................... (b) Addition of sodium hydroxide solution to the mixture neutralises the acid followed by the formation of a precipitate of aluminium hydroxide. (i) Write an ionic equation for the neutralisation of the acid. Include state symbols. [1] ......................................................................................................................................................................................................................................................................................................................................... (ii) Write an ionic equation for the formation of the aluminium hydroxide precipitate. Include state symbols. [1] ......................................................................................................................................................................................................................................................................................................................................... Q4 ‘Red lead’ is used in anti-corrosive paint and contains mainly the oxide Pb 3 O 4 . This can be produced by oxidising lead(II) oxide by oxygen gas. (a) Write an equation for this reaction. [2] ......................................................................................................................................................................................................................................................................................................................................... (b) Use oxidation states to show that the lead has been oxidised in this process. [2] ......................................................................................................................................................................................................................................................................................................................................... ......................................................................................................................................................................................................................................................................................................................................... ......................................................................................................................................................................................................................................................................................................................................... 1.1: Formulae and equations | 13 Unit 1 Practice questions