1. The paracetamol would take the longest time to dissolve in Expt. A.
Decreasing the temperature and the surface area of the solid decreases its rate of solution.
2. (a) Decreasing the temperature decreases the rate of a reaction because the particles are moving more slowly, so
• there are fewer collisions per second
• there is less energy per collision and fewer collisions will have enough energy for a reaction to occur.
2. (b) Decreasing the particle size of reactants increases the rate of a reaction because the surface area increases, making more particles available for reaction.
2. (c) Decreasing the concentration of reactants decreases the rate of reaction because fewer particles are available to collide. The reaction is slower if there are fewer collisions per second.
