Increasing the temperature affects the rate of reaction by which effect?

• A. Increases
• B. Decreases
• C. No effect
• D. Reverses

Answer: (A)

Raising the temperature speeds up reactions because it increases the average kinetic energy of the particles. With higher kinetic energy, particles collide more often and with greater energy, so a larger fraction of collisions has energy equal to or greater than the activation energy needed to start the reaction. Those more energetic, more frequent collisions make successful reactions happen more quickly, so the rate increases. The rate constant itself also rises with temperature, shown by the Arrhenius relationship, which reflects the growing proportion of particles capable of crossing the energy barrier as temperature goes up. This is why increasing temperature speeds the reaction, rather than slowing it down, having no effect, or reversing it.