## Delta H

$\Delta U=q+w$

AlyssaBei_1F
Posts: 99
Joined: Fri Sep 28, 2018 12:17 am

### Delta H

When does delta H replace q in delta u=q+w?

Emma Scholes 1L
Posts: 62
Joined: Fri Sep 28, 2018 12:18 am

### Re: Delta H

Delta H is equal to q when there is constant pressure.

chaggard
Posts: 37
Joined: Fri Sep 28, 2018 12:19 am

### Re: Delta H

This only holds true under constant pressure because if there no other work besides expansion on the system and the pressure throughout remains the same, the the change in enthalpy (delta H) is the same as the heat being consumed or released (q).

Cameron_Greenberg_3C
Posts: 60
Joined: Fri Sep 28, 2018 12:26 am

### Re: Delta H

Enthalpy by definition is heat at constant pressure, making it a state variable. So (delta)U= (delta)H + w at constant pressure