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Qv vs Qp

Posted: Thu Jan 30, 2020 11:44 am
by Brandon Valafar
What is the difference between qv and qp?

Re: Qv vs Qp

Posted: Thu Jan 30, 2020 12:00 pm
by rachelle1K
qv implies constant volume, whereas qp is constant pressure.

Re: Qv vs Qp

Posted: Thu Jan 30, 2020 12:37 pm
by Sidharth D 1E
Both of these are used to find enthalpy/delta H but also find change in internal energy which is q + w. Therefore, q can either be qp or qv depending on the given conditions.

Re: Qv vs Qp

Posted: Thu Jan 30, 2020 12:54 pm
by 805303639
Sidharth D 1E wrote:Both of these are used to find enthalpy/delta H but also find change in internal energy which is q + w. Therefore, q can either be qp or qv depending on the given conditions.


Enthalpy/delta H is equal to qp, the amount of heat released or absorbed at a constant pressure. Using qv implies that the change in the internal energy (U) equals qv. The work term w drops out of U = q + w under conditions of constant volume.

Re: Qv vs Qp

Posted: Thu Jan 30, 2020 1:35 pm
by 205405339
q at constant volume and q at constant pressure

Re: Qv vs Qp

Posted: Thu Jan 30, 2020 5:06 pm
by CameronDis2K
Both represent heat energy of deltaH, but one is used when the volume is constant and the pressure changes (Qv) and the other is when the pressure is constant but the volume is changing (Qp).

Re: Qv vs Qp

Posted: Thu Jan 30, 2020 5:13 pm
by Kallista McCarty 1C
qv is constant volume and qp is constant pressure

Re: Qv vs Qp

Posted: Thu Jan 30, 2020 8:42 pm
by Diana Andrade_4F
Qv is when there's constant volume while Qp is constant pressure