In the Arrhenius equation, what is the general effect of increasing temperature on the rate constant k?

• A. k increases
• B. k decreases
• C. k remains constant
• D. k becomes negative

Answer: (A)

Temperature changes affect the rate constant through the Arrhenius form k = A e^(-Ea/RT). Here Ea is the activation energy and A is the frequency factor. As temperature increases, the ratio Ea/RT decreases, making the exponent less negative. A less negative exponent means the exponential term grows, so k increases. Physically, more molecules have enough energy to overcome the activation barrier, leading to more successful collisions per unit time. Since the exponential term is always positive, k cannot become negative, and increasing temperature does not make k stay the same or decrease.