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### Delta H

Posted: Fri Feb 14, 2020 1:52 pm
How do you find the change in enthalpy for a reaction if you aren't given the values?

### Re: Delta H

Posted: Fri Feb 14, 2020 1:56 pm
I would have to see an example of a problem but if it is a reversible, isothermal process and temperature is constant, then Delta H would be 0 in all cases because there would be no heat transfer in and out of the system.

### Re: Delta H

Posted: Sun Feb 16, 2020 10:30 am
Delta H can usually be written as q. This is derived from the equation $\Delta H = \Delta U + P\Delta V$. $\Delta H = q + w -w = q$ , so $\Delta H = q$.

### Re: Delta H

Posted: Sun Feb 16, 2020 10:47 pm
Manav Govil 1B wrote:Delta H can usually be written as q. This is derived from the equation $\Delta H = \Delta U + P\Delta V$. $\Delta H = q + w -w = q$ , so $\Delta H = q$.

But this is only for when pressure is constant right?

### Re: Delta H

Posted: Tue Feb 18, 2020 5:02 pm
You would need to use the delta H equation and work with what you are given in the problem, mainly find what is constant and manipulate the equation to reflect that while looking for delta H.

### Re: Delta H

Posted: Sun Mar 08, 2020 11:19 pm
Hi oes anyone have a preferred online resource/chart they like to refer to for studying this topic? Like khan academy or a youtube video or something thanks!!

### Re: Delta H

Posted: Sun Mar 08, 2020 11:25 pm
ASetlur_1G wrote:
Manav Govil 1B wrote:Delta H can usually be written as q. This is derived from the equation $\Delta H = \Delta U + P\Delta V$. $\Delta H = q + w -w = q$ , so $\Delta H = q$.

But this is only for when pressure is constant right?

yes it is only when pressure is constant

### Re: Delta H

Posted: Sun Mar 08, 2020 11:29 pm
Mai V 4L wrote:Hi oes anyone have a preferred online resource/chart they like to refer to for studying this topic? Like khan academy or a youtube video or something thanks!!

### Re: Delta H

Posted: Mon Mar 09, 2020 2:25 am
You can find delta H either through products minus reactants, or Hess's law, or the Gibbs free energy equation delta G = delta H - T delta S

### Re: Delta H

Posted: Mon Mar 09, 2020 2:28 pm
Mai V 4L wrote:Hi oes anyone have a preferred online resource/chart they like to refer to for studying this topic? Like khan academy or a youtube video or something thanks!!