How does temperature affect rate?

• A. Temperature has no effect on rate
• B. Higher temperature decreases rate
• C. Temperature only affects catalyst
• D. Higher temperature increases rate because more collisions have enough energy to overcome activation energy

Answer: (D)

Temperature changes how fast molecules move and how often they collide. As temperature rises, particles have greater kinetic energy, so collisions happen more frequently and with more energy. Only collisions with energy at least equal to the activation energy can lead to product formation, so raising temperature increases the fraction of collisions that are effective. This means the rate constant rises with temperature, as described by the Arrhenius relationship, and the overall rate increases. The other ideas—no effect, rate decreasing with temperature, or temperature only affecting catalysts—don’t capture that the kinetic energy distribution and the activation-energy hurdle govern how quickly a reaction proceeds.