## Identifying endothermic vs exothermic

405318478
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### Identifying endothermic vs exothermic

If a problem doesn't specifically state if it is endothermic or exothermic, how do we determine which it is based off the stoichiometric equation?

Elena Bell 1C
Posts: 64
Joined: Thu Jul 11, 2019 12:16 am

### Re: Identifying endothermic vs exothermic

A reaction is exothermic if the products have more energy than the reactants, and it is endothermic if the reactants have more energy than the products. Usually, the reaction would give you a deltaH value if it is asking about temperature. DeltaH would be negative if the reaction is exothermic and positive if it is endothermic.

Eugene Chung 3F
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Joined: Wed Nov 15, 2017 3:03 am

### Re: Identifying endothermic vs exothermic

Elena Bell 1C wrote:A reaction is exothermic if the products have more energy than the reactants, and it is endothermic if the reactants have more energy than the products. Usually, the reaction would give you a deltaH value if it is asking about temperature. DeltaH would be negative if the reaction is exothermic and positive if it is endothermic.

This because energy is absorbed in form of heat in an endothermic reaction and energy is released in exothermic reaction.
Endothermic absorbs heat, and exothermic produces heat.

san_2F
Posts: 118
Joined: Sat Jul 20, 2019 12:15 am

### Re: Identifying endothermic vs exothermic

When delta H is negative, it's exothermic and when delta H is positive, the reaction is endothermic.

Noe BM 1J
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Joined: Sat Sep 07, 2019 12:17 am

### Re: Identifying endothermic vs exothermic

If delta H is negative, it means that the reaction is exothermic (it releases energy). If delta H is positive, the reaction is endothermic (it requires energy).

Ruth Glauber 1C
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Joined: Wed Sep 18, 2019 12:20 am

### Re: Identifying endothermic vs exothermic

Check if the products have more energy than the reactants to decide if its exothermic!

Sanjana K - 2F
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### Re: Identifying endothermic vs exothermic

You can also look at bond enthalpies or use Hess's Law to figure out the total energy on the reactants and products side or the energy needed to form/break the bonds and if delta H < 0, it's exothermic and if delta H > 0, it's endothermic.

Mitchell Koss 4G
Posts: 128
Joined: Sat Jul 20, 2019 12:17 am

### Re: Identifying endothermic vs exothermic

They will need to give you a delta H, so it it is positive, reaction is endothermic, but if it is negative, it is exothermic.

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