Exothermic vs. Endothermic

$K = \frac{k_{forward}}{k_{reverse}}$

Kennedi2J
Posts: 101
Joined: Wed Sep 18, 2019 12:20 am

Exothermic vs. Endothermic

By looking at energy profiles, how can you tell if it is showing an endothermic or exothermic reaction?

Nicholas Chin 1G
Posts: 100
Joined: Thu Jul 11, 2019 12:17 am

Re: Exothermic vs. Endothermic

Generally, if the reactant energy is higher than the product energy, the reaction is exothermic, and vice versa for endothermic.

VLi_2B
Posts: 99
Joined: Sat Sep 14, 2019 12:15 am

Re: Exothermic vs. Endothermic

This is a good video explaining exothermic vs endothermic reactions.

Posts: 97
Joined: Tue Feb 12, 2019 12:15 am

Re: Exothermic vs. Endothermic

When the reactants activation energy is higher than the products, then it is exothermic. In this case, potential energy is higher for reactants than products. When the products activation energy is higher than the reactants, then it is endothermic. In this case, the potential energy of the reactants are lower.

Lauren Tanaka 1A
Posts: 109
Joined: Sat Aug 17, 2019 12:18 am

Re: Exothermic vs. Endothermic

You can tell it is exothermic when the activation energy is higher for reactants than it is for products. If the activation energy for products is higher than for reactants then the reaction is endothermic.

KHowe_1D
Posts: 103
Joined: Thu Jul 25, 2019 12:15 am
Been upvoted: 1 time

Re: Exothermic vs. Endothermic

When reactant energy is higher than the product it is exothermic because energy is being released but if the reactant energy is lower than the product, it is endothermic because energy is required.

Hannah Pham
Posts: 104
Joined: Fri Aug 09, 2019 12:17 am

Re: Exothermic vs. Endothermic

It is an exothermic reaction when the activation energy of the reactants are higher than the products. If the activation energy of the products is higher than the reactants, then it is an endothermic reaction.

AronCainBayot2K
Posts: 101
Joined: Fri Aug 30, 2019 12:17 am

Re: Exothermic vs. Endothermic

If activation energy is higher than products, exothermic. If higher than reactants, endothermic.

saigorijavolu2k
Posts: 108
Joined: Sat Sep 28, 2019 12:15 am

Re: Exothermic vs. Endothermic

An exothermic reaction is one where the reactants have more energy than products. Exothermic releases energy, which is why the reactants should have more energy.

Nare Nazaryan 1F
Posts: 101
Joined: Fri Aug 09, 2019 12:17 am

Re: Exothermic vs. Endothermic

If reactant energy is higher than the product energy, the reaction is exothermic and the opposite for endothermic.

Posts: 74
Joined: Fri Sep 28, 2018 12:29 am

Re: Exothermic vs. Endothermic

Also just to add on, If the enthalpy is negative, the reaction is exothermic because heat is being released. If the enthalpy is positive, the reaction is endothermic because heat is being taken up by the rxn

Simon Ketema_1F
Posts: 16
Joined: Wed Nov 13, 2019 12:26 am

Re: Exothermic vs. Endothermic

A reaction is exothermic when the energy of the reactants is higher than the energy of the products. The energy difference is what is released into the surroundings as heat.

A reaction is endothermic when the energy of the reactants is lower than the energy of the products. The energy difference is what is required from the surroundings for the reaction to occur.

Shrayes Raman
Posts: 129
Joined: Sat Jul 20, 2019 12:15 am

Re: Exothermic vs. Endothermic

Exothermic reactions will have reactants higher than products and vice versa for endothermic.

Jarrett Peyrefitte 2K
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Joined: Sat Aug 24, 2019 12:16 am

Re: Exothermic vs. Endothermic

A reaction is exothermic when the reactants have more energy than products. Vice verso for endothermic.

J Medina 2I
Posts: 102
Joined: Wed Sep 25, 2019 12:17 am

Re: Exothermic vs. Endothermic

With reaction profiles to get delta H you have to subtract the end of the graph (products) by the beginning of the graph (reactants). So you have to remember that EXOTHERMIC reactions release energy into their surroundings meaning there is a loss of energy from the system ( meaning delta H = - ). So for exothermic reactions the end of the graph has to be lower than the beginning of the graph. And for ENDOTHERMIC reactions the end of the graph has to be higher than the beginning of the graph.