Answer:
METHOD 1: (surface area of a solid reactant) METHOD 2: (concentration or pressure of a reactant)
Step-by-step explanation:
METHOD 1: (surface area of a solid reactant) Increasing the surface area of a solid reactant exposes more of its particles to attack. This results in an increased chance of collisions between reactant particles, so there are more collisions in any given time and the rate of reaction increases.
METHOD 2: (concentration or pressure of a reactant) Increasing the concentration means that we have more particles in the same volume of solution. This increases the chance of collisions between reactant particles, resulting in more collisions in any given time and a faster reaction. As we increase the pressure of reacting gases, we increase the rate of reaction.