Enthalpy signs

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Nicole Garrido 2I
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Enthalpy signs

Postby Nicole Garrido 2I » Sat Jan 26, 2019 9:20 pm

When is the change in H, Enthalpy, positive and when is it negative?

Searra Harding 4I
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Re: Enthalpy signs

Postby Searra Harding 4I » Sat Jan 26, 2019 9:39 pm

Enthalpy will be positive when the reaction is endothermic meaning it absorbs heat. It is negative when the reaction is exothermic meaning giving off heat.

Anjali_Kumar1F
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Re: Enthalpy signs

Postby Anjali_Kumar1F » Sat Jan 26, 2019 10:24 pm

What is state property and what does it mean when enthalpy is state property.

Rami_Z_AbuQubo_2K
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Re: Enthalpy signs

Postby Rami_Z_AbuQubo_2K » Sat Jan 26, 2019 10:36 pm

When deltaH is positive, that mean that the reaction is going to absorb heat in order to proceed and is endothermic. When deltaH is negative, that means that the reaction is going to release heat into the environment and is exothermic.

davidryan3f
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Re: Enthalpy signs

Postby davidryan3f » Sun Jan 27, 2019 5:01 pm

Delta H is positive when the reaction is endothermic and Delta H is negative when the reaction is exothermic.

KarlaArevalo2F
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Re: Enthalpy signs

Postby KarlaArevalo2F » Sun Jan 27, 2019 9:06 pm

enthalpy is positive for endothermic because there is the need for heat, while enthalpy is negative for exothermic because heat is being released (exo=exit)

KarlaArevalo2F
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Re: Enthalpy signs

Postby KarlaArevalo2F » Sun Jan 27, 2019 9:06 pm

enthalpy is positive for endothermic because there is the need for heat, while enthalpy is negative for exothermic because heat is being released (exo=exit/out)

Diana Sandoval 1K
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Re: Enthalpy signs

Postby Diana Sandoval 1K » Sun Jan 27, 2019 9:30 pm

If it's positive it's endothermic and if it's negative it's exothermic.

Anand Narayan 1G
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Re: Enthalpy signs

Postby Anand Narayan 1G » Sun Jan 27, 2019 10:38 pm

When Delta H is positive, it's endothermic and when it's negative, it's exothermic

deepto_mizan1H
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Re: Enthalpy signs

Postby deepto_mizan1H » Mon Jan 28, 2019 10:03 am

Another aspect of this is thinking of the heat as a product or reactant, where in an endothermic reaction (+) it would require heat which can be considered as a reactant. In an exothermic reaction (-), where heat is given off, we can think of it as a product.

Jordan Lo 2A
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Re: Enthalpy signs

Postby Jordan Lo 2A » Mon Jan 28, 2019 10:49 am

deepto_mizan1H wrote:Another aspect of this is thinking of the heat as a product or reactant, where in an endothermic reaction (+) it would require heat which can be considered as a reactant. In an exothermic reaction (-), where heat is given off, we can think of it as a product.


This strategy is also helpful when thinking about le chatelier's principle and heat added/taken away to the system

Tinisha 1G
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Re: Enthalpy signs

Postby Tinisha 1G » Mon Jan 28, 2019 12:33 pm

Enthalpy is the amount of heat absorbed in a reaction. If the reaction is endothermic, it absorbs heat, so the sign of enthalpy is therefore postitive. It is negative if the reaction is exothermic, and so it is releasing heat, therefore is going to have a negative enthalpy.

Jason Ye 2I
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Re: Enthalpy signs

Postby Jason Ye 2I » Mon Jan 28, 2019 3:48 pm

Its positive when the reaction is endothermic and negative when it is exothermic

George Ghaly 2L
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Re: Enthalpy signs

Postby George Ghaly 2L » Tue Jan 29, 2019 7:45 pm

The enthalpy change is positive when a reaction gains heat (endothermic reaction) and is negative when the reactants release energy to the universe (exothermic reactions)


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