Question

how are the concentration of the reactants and reaction rate related?
a. increasing concentration decreases all reaction rates the same.

b. the concentration of reactants is a result of the reaction rate.

c. a change in concentration results in a change in the rate of a reaction.

d. increasing concentration increases all reaction rates the same.

Explanation:

• Option A: Increasing reactant concentration usually increases (not decreases) reaction rate, and different reactions respond differently, so A is wrong.
• Option B: Reaction rate depends on reactant concentration (not the other way around), so B is wrong.
• Option C: According to collision theory, changing reactant concentration changes the frequency of effective collisions, thus changing reaction rate. This is correct.
• Option D: Increasing concentration doesn't increase all reaction rates equally (different reactions have different rate laws and sensitivities to concentration), so D is wrong.

Answer:

C. A change in concentration results in a change in the rate of a reaction.