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Riya Shah 4H
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Joined: Wed May 02, 2018 3:00 am


Postby Riya Shah 4H » Fri Feb 01, 2019 3:32 pm

Is enthalpy calculated only for reactions at constant pressure?

MariahClark 2F
Posts: 60
Joined: Wed Nov 15, 2017 3:04 am

Re: Enthalpy

Postby MariahClark 2F » Fri Feb 01, 2019 4:10 pm

At constant pressure, the heat of reaction is equal to the enthalpy change of the system. Most chemical reactions occur at constant pressure, so enthalpy is more often used to measure heats of reaction than internal energy.

Posts: 62
Joined: Fri Sep 28, 2018 12:23 am

Re: Enthalpy

Postby michelle » Fri Feb 01, 2019 8:25 pm

I think enthalpy can be calculated under any condition, but maybe most questions will give a constant pressure, just temperature.

Shubham Rai 2C
Posts: 64
Joined: Fri Sep 28, 2018 12:27 am

Re: Enthalpy

Postby Shubham Rai 2C » Fri Feb 01, 2019 8:35 pm

Enthalpy is equal to the internal energy plus the pressure times the volume. Thus, it can be calculated for any reactions. For reactions with a fixed volume, the change in v is 0, therefore, the enthalpy value equals the internal energy.

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