Questions where students often pick the tempting wrong answer — make sure you know the right one:
How does a catalyst speed up a reaction?✗ A catalyst lowers the activation energy of the original reaction pathway.✓ It provides an alternative reaction pathway with a lower activation energy.
Why does increasing temperature increase the rate of reaction significantly?✗ Particles collide much more frequently at higher temperature, which is the main reason for the rate increase.✓ Mainly because a much larger fraction of collisions have energy at least equal to the activation energy; collision frequency increases only slightly.
Can you determine the order of a reaction with respect to a reactant from the balanced equation?✗ The order of reaction with respect to each reactant equals its coefficient in the balanced equation.✓ No — orders must be determined experimentally; they often differ from the stoichiometric coefficients.
How does the rate of an SN2 reaction depend on concentrations?✗ SN2 reactions are first order overall because only the substrate matters.✓ Rate is first order in both substrate AND nucleophile (overall second order) because both are involved in the rate-determining step.
Increasing temperature increases the rate mainly because:✗ More collisions occur✓ A greater fraction of collisions exceed E_a
Practise Kinetics & Equilibria — free games
Test yourself with these quick revision games for this topic:
