How Fast? The Rate of Chemical Change · Paper 1 — Free Chemistry SL Practice Questions

A student investigates the effect of concentration the rate of reaction between magnesium ribbon and excess hydrochloric acid by measuring the time taken to collect $50 \ \text{cm}^3$ of hydrogen gas. Which statement correctly explains why increasing the concentration of hydrochloric acid increases the rate of this reaction?

A student adds 2.0 g of calcium carbonate chips to 50 cm³ of 1.0 mol dm⁻³ hydrochloric acid at 20 °C and records the mass loss over 2 minutes. The experiment is repeated at 40 °C, and the rate of reaction is observed to be greater. Which statement correctly explains why increasing temperature increases the rate of this reaction?

A factory produces hydrogen gas by reacting zinc with dilute sulfuric acid. The same mass of zinc is used in each experiment. Which statement correctly explains why zinc powder produces hydrogen gas at a faster rate than zinc granules?

Magnesium ribbon (excess) is reacted with hydrochloric acid at 25 °C and the initial rate of hydrogen gas production is measured. The experiment is repeated under identical conditions except the concentration of hydrochloric acid is halved. According to collision theory, what is the ratio of the initial rate at the higher concentration to the initial rate at the lower concentration?