A student carries out an experiment to investigate the rate of reaction between excess marble chips (CaCO3\text{CaCO}_3CaCO3) and 50 cm3 of 2.0 mol dm-3 hydrochloric acid (HCl\text{HCl}HCl).
Which of the following changes to the reaction conditions would result in a decrease in the initial rate of reaction?
Using the same mass of marble chips as a fine powder rather than medium-sized chips
Using 100 cm3100\text{ cm}^3100 cm3 of 1.0 mol dm−31.0\text{ mol dm}^{-3}1.0 mol dm−3 HCl(aq)\text{HCl(aq)}HCl(aq) instead of 50 cm350\text{ cm}^350 cm3 of 2.0 mol dm−32.0\text{ mol dm}^{-3}2.0 mol dm−3 HCl(aq)\text{HCl(aq)}HCl(aq)
Heating the reaction mixture from 293 K293\text{ K}293 K to 308 K308\text{ K}308 K
Using 100 cm3100\text{ cm}^3100 cm3 of 2.0 mol dm−32.0\text{ mol dm}^{-3}2.0 mol dm−3 HCl(aq)\text{HCl(aq)}HCl(aq) instead of 50 cm350\text{ cm}^350 cm3 of 2.0 mol dm−32.0\text{ mol dm}^{-3}2.0 mol dm−3 HCl(aq)\text{HCl(aq)}HCl(aq)
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.