A student investigated the effect of temperature on the rate of reaction between sodium thiosulfate solution and dilute hydrochloric acid.
The concentration of the sodium thiosulfate solution was kept at 0.15 mol/dm³.
State one other variable that must be kept constant during this investigation.
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.