Question

question 4 of 10
how does the concentration of reactants affect the rate of a reaction?
a. increasing the concentration decreases the reactions activation energy.
b. increasing the concentration increases the molecules collision frequency.
c. increasing the concentration increases the kinetic energy of the molecules.
d. increasing the concentration increases the temperature of the solution.

Explanation:

• Option A: Activation energy is related to the nature of the reaction and catalysts, not concentration.
• Option B: According to the collision theory, when the concentration of reactants increases, there are more reactant molecules in a given volume. This leads to a higher probability of collisions between molecules, thus increasing the collision frequency.
• Option C: Kinetic energy of molecules is mainly affected by temperature, not concentration.
• Option D: Concentration change does not directly increase the temperature of the solution (unless there is a heat - generating reaction, but this is not a general effect of concentration on reaction rate).

Answer:

B. Increasing the concentration increases the molecules' collision frequency.