Sulfur dioxide can be liquefied when under pressure and cooled. Liquid sulfur dioxide forms a gas when warmed.
Explain what happens to the sulfur dioxide molecules when liquid sulfur dioxide is warmed to form a gas.
Bromine reacts with cold aqueous sodium hydroxide to form a mixture of sodium bromide, NaBr\text{NaBr}NaBr, and sodium bromate(I), NaBrO\text{NaBrO}NaBrO.
Write a chemical equation for this reaction.
Sulfuric acid reacts with copper(II) oxide to form a solution containing copper(II) sulfate.
CuO(s)+H2SO4(aq)→CuSO4(aq)+H2O(l) \text{CuO}(\text{s}) + \text{H}_2\text{SO}_4(\text{aq}) \rightarrow \text{CuSO}_4(\text{aq}) + \text{H}_2\text{O}(\text{l}) CuO(s)+H2SO4(aq)→CuSO4(aq)+H2O(l)Crystals of hydrated copper(II) sulfate, CuSO4⋅5H2O\text{CuSO}_4\cdot 5\text{H}_2\text{O}CuSO4⋅5H2O, can be obtained from this solution.
CuSO4+5H2O→CuSO4⋅5H2O \text{CuSO}_4 + 5\text{H}_2\text{O} \rightarrow \text{CuSO}_4\cdot 5\text{H}_2\text{O} CuSO4+5H2O→CuSO4⋅5H2OAn excess of sulfuric acid is reacted with 0.160 mol0.160\text{ mol}0.160 mol of copper(II) oxide.
Show, by calculation, that the maximum theoretical mass of hydrated copper(II) sulfate that can be made is 40.0 g40.0\text{ g}40.0 g. [MrM_rMr of CuSO4⋅5H2O=250\text{CuSO}_4\cdot 5\text{H}_2\text{O} = 250CuSO4⋅5H2O=250]
In an experiment using 0.160 mol0.160\text{ mol}0.160 mol of copper(II) oxide, with an excess of sulfuric acid, the mass of hydrated copper(II) sulfate obtained is 28.4 g28.4\text{ g}28.4 g.
Suggest two reasons why the actual mass obtained is less than the maximum theoretical mass.
80 exam-style questions on Edexcel IGCSE Chemistry Chemical formulae, equations and calculations. Each one has a worked solution and a mark scheme showing where the marks go.