Complete the equation by inserting state symbols for the products: $\text{Zn}(s)+2\text{HCl}(aq)\rightarrow\text{ZnCl}_2(\ )+\text{H}_2(\ )$.
Describe how the graph in Fig. 5.1 indicates that the rate of reaction falls with time.
Explain in terms of collision theory why the rate of reaction falls with time.
Describe and explain the change in reaction rate when powdered zinc is used.
Calculate the volume of hydrogen gas produced at room temperature and pressure when excess zinc reacts with $16.0\text{ cm}^3$ of $0.400\text{ mol dm}^{-3}$ hydrochloric acid. Give your answer to two significant figures.
Complete the reaction pathway diagram in Fig. 5.2 so that it shows the reactants and products, a labelled arrow for the activation energy $E_a$, and a labelled arrow for the enthalpy change $\Delta H$.
Describe the observations seen when a few drops of aqueous ammonia are added, and when excess aqueous ammonia is added, to an aqueous solution containing zinc ions.
Describe how pure, dry zinc chloride crystals are prepared after excess zinc has reacted with dilute hydrochloric acid.