Rate of reaction — Grade 12 Past Paper Questions

Copper oxidation by concentrated nitric acid producing nitrogen dioxide gas. Apply collision theory to explain rate changes, compare instantaneous rates, calculate gas production time, determine hydronium ion concentration in the final solution, and predict effects of reactant changes on product yield.

Analyse a catalysed reaction's energy profile diagram. Determine whether the reaction is exothermic or endothermic, identify the activated complex graphically, and read the activation energy value for the forward catalysed pathway.

Maxwell-Boltzmann distribution analysis at elevated temperature. Select the correct graph representation, explain how temperature shift affects particle kinetics, and determine the direction a catalyst shifts the activation energy line on the diagram.

Experimental measurement of carbon dioxide gas production when magnesium carbonate reacts with excess hydrochloric acid. Define reaction rate, explain rate changes via collision theory, calculate CO₂ production rate in dm³·s⁻¹, and determine the initial mass of magnesium carbonate.

Multiple-choice page comparing factors affecting reaction rate between magnesium and hydrochloric acid, including effects of particle size and temperature, and identifying factors that change the area under a Maxwell-Boltzmann distribution curve.

Multiple-choice covering energy profile analysis for reversible reactions, identifying activation energy components, effect of catalysts, and acid-base indicator equilibrium shifts using Le Chatelier's principle.

Multiple-choice page on organic reaction classification: identifying whether an alkene-HBr reaction is addition or substitution and determining the major product via Markovnikov's rule; and recognizing which factors change the area under a Maxwell-Boltzmann distribution.