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Enthalpy Formula

Posted: Sun Feb 09, 2020 6:31 pm
by Jasmine 2C
In lecture, we went over 3 methods to calculate enthalpy as well as ΔH = H(products) - H(reactants). In the textbook, they have the formula ΔH = ΔU + PΔV. Are we not allowed to use this formula (alongside ΔU = q + w) to calculate the change in enthalpy?

Re: Enthalpy Formula

Posted: Sun Feb 09, 2020 6:42 pm
by Jared_Yuge
We can definitely use that equation, cause its just a reworked 1st law equation. Under constant pressure q=delta H and w= -P deltaV

Re: Enthalpy Formula

Posted: Sun Feb 09, 2020 6:45 pm
by Angela Wu-2H
The formula is basically derived from each other, so I believe we could use both.

qp=delta H so
delta U = q+w ------> delta U = delta H + w
w = -p*delta V -------> delta U = delta H -p*delta V
solve for delta H so...
delta H = delta U + p*delta V