Sodium thiosulfate solution reacts with dilute hydrochloric acid to form a cloudy precipitate of sulfur.
Na2S2O3(aq)+2HCl(aq)→2NaCl(aq)+H2O(l)+S(s)+SO2(g) \text{Na}_2\text{S}_2\text{O}_3(\text{aq}) + 2\text{HCl}(\text{aq}) \rightarrow 2\text{NaCl}(\text{aq}) + \text{H}_2\text{O}(\text{l}) + \text{S}(\text{s}) + \text{SO}_2(\text{g}) Na2S2O3(aq)+2HCl(aq)→2NaCl(aq)+H2O(l)+S(s)+SO2(g)A student wants to investigate how the rate of this reaction is affected by temperature. They plan to use the 'disappearing cross' experiment.
Devise a method the student could use to obtain a range of results at different temperatures.
127 exam-style questions on Edexcel GCSE Chemistry 8.1 Rates of reaction, covering 8.1.1 Measuring and interpreting rates of reaction, 8.1.2 Collision theory and the factors affecting rate, and 8.1.3 Catalysts and enzymes. Each one has a worked solution and a mark scheme showing where the marks go.