## Activation Energy and Energy released/absorbed

Arrhenius Equation: $\ln k = - \frac{E_{a}}{RT} + \ln A$

Siddiq 1E
Posts: 106
Joined: Fri Aug 09, 2019 12:15 am

### Activation Energy and Energy released/absorbed

I was looking at the graphs for endothermic and exothermic reactions and I wanted clarification about whether in an endothermic reaction, the amount of activation energy includes the amount of energy that is absorbed in the reaction?

Ipsita Srinivas 1K
Posts: 50
Joined: Mon Jun 17, 2019 7:24 am

### Re: Activation Energy and Energy released/absorbed

The energy absorbed includes the activation energy needed for the reaction to take place for both endothermic and exothermic reactions. In the case of exothermic reactions, energy related on product formation is more than energy absorbed for overcoming energy barrier, and hence there is a net loss of energy.

Jared_Yuge
Posts: 100
Joined: Sat Aug 17, 2019 12:17 am

### Re: Activation Energy and Energy released/absorbed

activation energy is always accounted for in both endo and exothermic reactions, but that doesn't determine net loss/gain of energy

Frank He 4G
Posts: 50
Joined: Tue Nov 12, 2019 12:19 am

### Re: Activation Energy and Energy released/absorbed

The net energy change of a reaction includes the activation energy, not the other way around, for both endothermic and exothermic reactions. In general, if you are trying to determine the net energy change from a reaction profile, all you need to look at is the initial and final energies. Remember that reaction profiles represent the energy as the reaction proceeds, so if the curve goes higher, energy is being put in, and if the curve slopes downwards, energy is being released. Thus, a curve that goes up and then goes down the same amount means that the reaction absorbs energy and then releases the same amount of energy.