The Activation Energy and Rate Constant Relationship
How does the temperature change affect the rate constant of a reaction?
What is the relationship between the activation energy and the rate constant when the temperature decreases?
The Effect of Temperature on Rate Constant and Activation Energy
When the temperature of a reaction decreases, the rate constant of the reaction also decreases. This relationship is governed by the Arrhenius equation, which relates the rate constant, activation energy, and temperature.
In this case, with an activation energy of 87 kJ/mol for a reaction in the citric acid cycle, the change in temperature from 37°C to 15°C will result in a decrease in the rate constant.
The rate constant of a chemical reaction is influenced by the activation energy required for the reaction to proceed. As temperature decreases, the particles involved in the reaction have lower kinetic energy, leading to a decrease in the rate of collision and subsequent reaction. This results in a lower rate constant for the reaction.
The Arrhenius equation, k = Ae-Ea/RT, demonstrates the exponential relationship between the rate constant, activation energy, and temperature. By analyzing this equation, we can see that a decrease in temperature results in a decrease in the rate constant, as the exponential term in the equation becomes smaller.
Therefore, in the scenario of the citric acid cycle reaction with an activation energy of 87 kJ/mol, the rate constant will decrease when the temperature falls from 37°C to 15°C. This decrease in rate constant signifies a slower reaction rate at lower temperatures due to the reduced kinetic energy of the reacting particles.