Activation Energy

Arrhenius Equation:

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Activation Energy

Postby eduardomorales5 » Mon Mar 16, 2020 1:00 pm

How does an increase in temperature lower the activation energy? If we were given two reactions, 1 endothermic and the other exothermic, how would an increase in temperature affect the rate constant?

Daniel Honeychurch1C
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Re: Activation Energy

Postby Daniel Honeychurch1C » Mon Mar 16, 2020 2:00 pm

Increasing temperature does not affect activation energy. At a higher temperature, faster moving molecules can collide to overcome the activation energy more frequently. For an exothermic reaction, a higher temperature would favor the reactants, so the forward rate constant would decrease. For an endothermic reaction, a higher temperature would favor the products, so the forward rate constant would increase. This is related to activation energy because a higher temperature favors the direction of the favorable reaction based on which has a higher activation energy (exothermic - higher activation energy for the reverse reaction, endothermic- higher activation energy for the forward reaction).

Ellen Amico 2L
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Re: Activation Energy

Postby Ellen Amico 2L » Mon Mar 16, 2020 2:22 pm

An increase in temperature doesn't affect the activation energy. In the case of an endothermic reaction, increasing the temperature causes the forward rate constant to increase because it'll be easier to overcome the energy barrier bc there will be more energy (however, the value of the barrier doesn't change). The opposite is true for exothermic – the reverse rate constant increases when temp increases.

Aiden Metzner 2C
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Joined: Wed Sep 18, 2019 12:21 am

Re: Activation Energy

Postby Aiden Metzner 2C » Mon Mar 16, 2020 4:04 pm

If the reaction is endothermic, increasing the temperature lowers the activation energy because it adds energy to the system. For the endothermic reaction this makes it easier for the reactants to form products, this is the opposite for an exothermic reaction.

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