## delta U = delta H - P delta V

Tiffany Chao 2H
Posts: 117
Joined: Fri Aug 09, 2019 12:17 am

### delta U = delta H - P delta V

Am I supposed to use this equation to find internal energy of a system that's at constant pressure?

Thanks

dtolentino1E
Posts: 101
Joined: Thu Jul 11, 2019 12:17 am

### Re: delta U = delta H - P delta V

yes!

the change in internal energy (delta U) is usually calculated as heat (q) + work (w), but at constant pressure, q = delta H and w = -P(deltaV)

Kristina Rizo 2K
Posts: 105
Joined: Wed Sep 18, 2019 12:19 am

### Re: delta U = delta H - P delta V

dtolentino1E wrote:yes!

the change in internal energy (delta U) is usually calculated as heat (q) + work (w), but at constant pressure, q = delta H and w = -P(deltaV)

So when P is not constant we go back to delta U= q +w?

Helen Struble 2F
Posts: 97
Joined: Sat Aug 24, 2019 12:17 am

### Re: delta U = delta H - P delta V

dtolentino1E wrote:yes!

the change in internal energy (delta U) is usually calculated as heat (q) + work (w), but at constant pressure, q = delta H and w = -P(deltaV)

How would this change for a constant volume set up? Is delta U no longer equal to qp in that scenario?