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Things to keep in mind. From the 2014 exam.
The expected emphasis in explaining enzyme activity in chemistry is very much about reference to structure. 'Denaturation' is not sufficient. Students should be aware of the significance of the tertiary structure and active site in enzyme activity. Key factors that affect these and reduce enzyme activity are high temperature and change in pH.
The reduction half-equations provided in the electrochemical series (Table 2 in the Data Book) include equilibrium arrows because the direction of each half-equation is determined by the combination of oxidant and reductant used in the reaction. Equilibria between an oxidant, its conjugate reductant and electrons are not established at the electrodes. Students should be aware that oxidation (the loss of electrons) occurs at the anode and reduction (the gain of electrons) occurs at the cathode.
Students should be aware that the introduction of a catalyst does not increase the number of collisions but rather increases the proportion of collisions occurring that are successful. Students should be aware of the impact of the key factors that increase rate – higher temperature, higher concentration, larger surface area and the presence of a catalyst – in terms of collision theory
When two profiles are drawn on the same grid students should be encouraged to label them. Students should be reminded that energy profiles do not have a horizontal axis.
When 'n' glucose molecules link together to form a polysaccharide 'n-1' H₂O molecules are condensed out.
The following two understandings were overlooked by students:  only primary alkanols can be oxidised to acids  when determining the systematic name, the C atoms are numbered so that the functional group is on the lowest possible numbered C atom, within the constraint the C atoms must be numbered from one end of the chain to the other.
A calibration curve is most accurate between the limits of the `concentrations of the standard solutions used during the calibration,
The most effective way to balance the equation for a redox reaction is to consider the relevant half-equations.
While adding the inert gas at constant volume does increase the total pressure in the reaction vessel, it does not affect the sum of the pressures exerted by – or the concentrations of – the components of the equilibrium mixture and has no effect on the position of equilibrium.
It is appropriate that when dealing with heats of combustion, chemical reasons for the variety of units – kJ mol^–1, kJ g^–1, kJ L^–1 – for different fuels are discussed. Pure substances can be expressed in kJ mol^–1 , however, mixtures are expressed in kJ g^–1, kJ L^–1.