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.
In an exothermic reaction, what happens energetically with the bonds?✗ Bond breaking releases energy and bond making absorbs energy.✓ Energy released forming new bonds exceeds energy absorbed breaking existing bonds.
On a reaction profile, activation energy is shown by:✗ height of products above reactants✓ height of peak above reactants
At dynamic equilibrium, what is happening to the reactions?✗ Both reactions stop because the system has reached balance.✓ Forward and reverse reactions continue at equal rates; concentrations remain constant.
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.
Practise Rates & Equilibrium — free games
Test yourself with these quick revision games for this topic:
