Exothermic Reactions

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Briana Yik 1H
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Joined: Fri Sep 28, 2018 12:20 am

Exothermic Reactions

Postby Briana Yik 1H » Tue Jan 08, 2019 11:18 pm

How do I find out if a reaction is exothermic or endothermic? Thank you!

Sarah Kiamanesh 1D
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Joined: Fri Sep 28, 2018 12:22 am

Re: Exothermic Reactions

Postby Sarah Kiamanesh 1D » Wed Jan 09, 2019 10:29 am

You basically need to know the enthalpies of all the products and reactants. These are set values provided in tables.
If the sum of the enthalpies of the reactants is greater than those of the products, the reaction will be exothermic. It releases energy into the system.
If the sum of the enthalpies of the products is greater than those of the reactants, the reaction will be endothermic. It absorbs energy.

Christopher Anisi 2K
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Joined: Fri Sep 28, 2018 12:21 am

Re: Exothermic Reactions

Postby Christopher Anisi 2K » Wed Jan 09, 2019 7:35 pm

They usually provide the delta H of the reaction, which is also known as enthalpy which will described in more detail in lecture. If the delta H, is positive that means that the reaction is endothermic, if the delta H is negative that means that the reaction is exothermic. Depending on whether heat is being added or removed to the respective reactions allows you to tell you how the products and reactants will shift during equilibrium.

Katelyn Pham 4E
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Joined: Fri Sep 28, 2018 12:21 am

Re: Exothermic Reactions

Postby Katelyn Pham 4E » Fri Jan 11, 2019 2:28 pm

Also, if a reaction is exothermic while forming products, then heating will favor reaction formations.

LeannaPhan14BDis1D
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Joined: Fri Sep 28, 2018 12:16 am

Re: Exothermic Reactions

Postby LeannaPhan14BDis1D » Fri Jan 11, 2019 3:18 pm

IN the lecture today he wrote/ said
when pressure changes
when k does change
If rxn requires heat (endothermic) while forming product then heating will favor P formation.
If rxn gives off heat (exothermic) while forming product then heating will favor R formation.
hope this helps :)

Nico Edgar 4L
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Joined: Fri Sep 28, 2018 12:19 am

Re: Exothermic Reactions

Postby Nico Edgar 4L » Sun Jan 13, 2019 1:20 pm

An exothermic reaction will release energy, so the products have less energy than the reactants. An endothermic reaction will need energy, so the products have more energy then the reactants.

Jonathan Pai 2I
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Joined: Fri Sep 28, 2018 12:27 am

Re: Exothermic Reactions

Postby Jonathan Pai 2I » Sun Jan 13, 2019 2:46 pm

Stability also relates to exo or endo, such as the HW question using a halogen, which makes us have to know that halogens are stable diatomically, so dissociating to monotomic would have to be endothermic.

Angela Cong 3C
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Joined: Fri Sep 28, 2018 12:25 am

Re: Exothermic Reactions

Postby Angela Cong 3C » Sun Jan 13, 2019 2:50 pm

in the modules he also mentioned you can tell if a reaction is exo or endo by looking at the lewis structure depending on whether or not they form or break bonds

Aiden Atoori 1C
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Joined: Fri Sep 28, 2018 12:24 am

Re: Exothermic Reactions

Postby Aiden Atoori 1C » Sun Jan 13, 2019 3:04 pm

So if the sum of the enthalpies of the reactants is greater than the products, the reaction will be exothermic.

Hedi Zappacosta 1E
Posts: 66
Joined: Fri Sep 28, 2018 12:27 am

Re: Exothermic Reactions

Postby Hedi Zappacosta 1E » Mon Jan 14, 2019 9:25 am

In lecture, Dr. Lavelle explained that adding heat to an endothermic reaction will favor the formation of products and adding heat to an exothermic reaction will favor the formation of the reactants.


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