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Exothermic vs. Endothermic

Posted: Wed Mar 13, 2019 12:59 am
If a reaction has activation energy, is it always endothermic? If not, is it because deltaG plus the activation energy is still less than zero? or is there something else?

Re: Exothermic vs. Endothermic

Posted: Wed Mar 13, 2019 1:03 am
All reactions use activation energy, but exothermic reactions just produce more energy than they consumed. So to answer your question, having activation energy does not declare a reaction being endothermic vs exothermic. They could have the same Ea, but they depend on the initial and final energy use. Exothermic has a negative G, while endothermic has a positive G.

Re: Exothermic vs. Endothermic

Posted: Wed Mar 13, 2019 8:49 pm
An endothermic reaction has a higher energy barrier in the forward direction so k forward is greater than k reverse which means that if you heated up a endothermic reaction the k forward would increase so the K overall would also increase and products would be favored

For an exothermic reaction, the activation energy is lower in the forward direction so if you heat up an exothermic reaction k reverse will increase which will result in a lower K and the reaction will favor reactants

Re: Exothermic vs. Endothermic

Posted: Sun Mar 17, 2019 1:28 am
Both endothermic and exothermic reactions have Ea, however endothermic reactions will have a larger energy barrier to go over.

Re: Exothermic vs. Endothermic

Posted: Sun Mar 17, 2019 2:02 am
a reaction is endothermic is the E(a) (activation energy) of the forward reaction is higher than the reverse reaction. therefore, if the temperature increases, the rate constant of the forward reaction will increase because k is dependent on temperature.

Re: Exothermic vs. Endothermic

Posted: Sun Mar 17, 2019 7:49 am
Every reaction has activation energy since it is the minimum amount of energy needed to be able to undergo the reaction. Activation energy is the difference in the energy between the transition state and the reactants.

Re: Exothermic vs. Endothermic

Posted: Tue Mar 03, 2020 12:32 am
An exothermic reaction- the activation energy is lower in the forward direction so if you heat up an exothermic reaction k reverse will increase which will result in a lower K and the reaction will favor reactants

Re: Exothermic vs. Endothermic

Posted: Sun Mar 08, 2020 6:52 pm
Activation energy plays a role in both.

Re: Exothermic vs. Endothermic

Posted: Sun Mar 08, 2020 9:30 pm
activation energy is in both types of reactions

Re: Exothermic vs. Endothermic

Posted: Sun Mar 08, 2020 9:32 pm
All reactions will have some sort of activation energy. What determines if a reaction is exothermic or endothermic is the final value of the amount of energy still within the system.

Re: Exothermic vs. Endothermic

Posted: Sun Mar 08, 2020 10:22 pm
Endothermic and exothermic reactions both have an activation energy. But for endothermic reactions, the products have higher energy than the reactants and for exothermic reactions, the products have lower energy than the reactants.