1. Aluminium reacts with warm dilute hydrochloric acid to give aluminium chloride solution and hydrogen. Explain why the reaction of dilute hydrochloric acid with aluminium foil is fairly slow whereas the reaction with the same mass of aluminium powder can be extremely vigorous. 2. This question involves reactions that may be unfamiliar. That doesn't matter in the least. Everything you need to know has been explained on the page about the effect of concentration on rates. a) 1-bromopropane reacts with sodium hydroxide solution to give propan-1-ol. The hydroxide ions replace the bromine in the organic molecule. CH3CH2CH2 Br CH3CH2CH2OH + This is a simple reaction involving a collision between the l-bromopropane and the hydroxide ions. What do you think the effect would be if you doubled the concentrations of both reactants? Explain your answer. OH Br 4. a) Sketch the Maxwell-Boltzmann Distribution showing the numbers of molecules in a gas having a particular energy at a temperature T. b) Show how this distribution changes if you increase the temperature by a small amount to Tht. c) Use your graphs to explain why a small increase in temperature can cause a much greater proportional increase in the rate of reaction - for example, why a 10 K increase in temperature from 290 to 300 K will roughly double the rate of many reactions. d) Give any other minor factor(s) also causing rates of reaction to increase as temperature increases