Question

unit 10 final exam
as the temperature of a reaction is increased, the rate of the reaction increases because the _______.
a) reactant molecules collide less frequently
a) reactant molecules collide more frequently and with greater energy per collision
c) activation energy is lowered
d) reactant molecules collide less frequently and with greater energy per collision
e) reactant molecules collide more frequently with less energy per collision

Explanation:

To determine the correct answer, we analyze the effect of temperature on reaction rates using collision theory:

• Option a: Incorrect. Increasing temperature increases molecular motion, so collisions become more frequent, not less.
• Option b: Correct. Higher temperature means molecules move faster, collide more often, and have more kinetic energy (greater energy per collision), which increases the chance of successful reactions (overcoming activation energy).
• Option c: Incorrect. Temperature does not lower activation energy; catalysts do that.
• Option d: Incorrect. Collision frequency increases with temperature, not decreases.
• Option e: Incorrect. Higher temperature gives molecules more energy, not less, per collision.

Answer:

b) reactant molecules collide more frequently and with greater energy per collision