Endothermic v. Exothermic Reactions

Moderators: Chem_Mod, Chem_Admin

ClaireHW
Posts: 60
Joined: Fri Sep 29, 2017 7:07 am
Been upvoted: 1 time

Endothermic v. Exothermic Reactions

Postby ClaireHW » Mon Dec 04, 2017 9:35 pm

Hi, could someone explain the difference between endothermic and exothermic reactions and give an example of each?

Thanks!

(Claire Woolson Dis. 3J)

Christy Lee 2H
Posts: 73
Joined: Fri Sep 29, 2017 7:07 am
Been upvoted: 1 time

Re: Endothermic v. Exothermic Reactions

Postby Christy Lee 2H » Tue Dec 05, 2017 12:08 am

In endothermic reactions, heat is consumed or absorbed to move the reaction forward. In exothermic reactions, heat is released or given off. You can think of endothermic reactions as having heat as a reactant, whereas exothermic reactions have heat as a product.

Janine Chan 2K
Posts: 71
Joined: Fri Sep 29, 2017 7:04 am

Re: Endothermic v. Exothermic Reactions

Postby Janine Chan 2K » Tue Dec 05, 2017 12:13 am

Reactions that include bond breaking are generally endothermic. EX: Cl2 <--> 2Cl. Combustion reactions are almost always exothermic.

dstemp
Posts: 20
Joined: Fri Sep 29, 2017 7:07 am

Re: Endothermic v. Exothermic Reactions

Postby dstemp » Thu Dec 07, 2017 7:49 pm

In my discussion section, the delta H for a reaction was -100.2 KJ/mol. My TA said that the negative sign means the reaction is exothermic (heat's produced) so the reaction shifts to the right. However, don't exothermic favor the formation of reactants? Could somebody please clarify this for me?

Mitch Walters
Posts: 45
Joined: Fri Sep 29, 2017 7:07 am

Re: Endothermic v. Exothermic Reactions

Postby Mitch Walters » Thu Dec 07, 2017 7:55 pm

In endothermic energy is being consumed, in other words it requires energy in order to function. In an exothermic reaction energy is being released. Often times, exothermic reactions are used to power endothermic reactions.

Rachel Wang
Posts: 49
Joined: Fri Sep 29, 2017 7:04 am

Re: Endothermic v. Exothermic Reactions

Postby Rachel Wang » Fri Dec 08, 2017 10:25 pm

Endothermic: requires heat to carry forward the reaction and therefore deltaH is on the left. Increasing heat in this case would produce more products.
Exothermic: releases heat once reaction has occurred and therefore deltaH is on the right. Increasing heat causes equilibrium to favor reactants and shift left.

GabrielGarciaDiscussion1i
Posts: 71
Joined: Fri Sep 29, 2017 7:04 am
Been upvoted: 1 time

Re: Endothermic v. Exothermic Reactions

Postby GabrielGarciaDiscussion1i » Fri Dec 08, 2017 11:20 pm

Everyone is explaining what Endothermic and Exothermic are but here are some examples you can look up if you wanna learn more or see:

Endothermic:
dissolving ammonium chloride in water
mixing water and ammonium nitrate

Exothermic:
any combustion reaction
a neutralization reaction

Jesus Rodriguez 1J
Posts: 53
Joined: Sat Jul 22, 2017 3:00 am

Re: Endothermic v. Exothermic Reactions

Postby Jesus Rodriguez 1J » Sat Dec 09, 2017 10:19 am

In an endothermic reaction the system absorbs energy(delta H>0), where as in exothermic reactions heat is released(delta H<0).
If you click on this link http://antoine.frostburg.edu/chem/senes ... ples.shtml , it will take you several examples of each type of reaction.

Clarissa Molina 1D
Posts: 55
Joined: Fri Sep 29, 2017 7:04 am

Re: Endothermic v. Exothermic Reactions

Postby Clarissa Molina 1D » Sat Dec 09, 2017 5:51 pm

How does an endothermic or exothermic reaction affect the direction of the reaction?

alyssawhite1L
Posts: 20
Joined: Fri Sep 29, 2017 7:05 am

Re: Endothermic v. Exothermic Reactions

Postby alyssawhite1L » Sun Dec 10, 2017 12:20 am

In an endothermic reaction, heat is absorbed and can therefore be thought of as basically a reactant. Therefore increasing the temp would cause the reaction to favor the products. Decreasing the temp would cause the rxn to favor the reactants.

For exothermic reactions, heat is released. Therefore heat is technically a product of the reaction. Therefore an increase in temp would favor reactants. A decrease in temp would favor products. :)))


Return to “Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions”

Who is online

Users browsing this forum: No registered users and 1 guest