Posted by Dan on .
Change in enthalpy problem. Consider the reaction represented below. Referring to the data in the table below, calculate the standard enthalpy change for the reaction at 25 degrees C.
Standard enthalpy of formation in kJ/mol:
I am sure this isn't a hard problem, but I can't really remember how to do it.
delta Hreaction = delta Hproducts - delta Hreactants
Ok, so I have DeltaHrxn=(X+90)-(143+90). How do you calculate the enthalpy of O2 (X above) when it is not given to you. Am I even doing that right?
No. Re-read my answer. I said
PRODUCTS - REACTANTS.
You have one of the reactants on the product side.
DHrxn = DH products - DH reactants.
DHrxn = (O2 + NO2) - (O3 + NO)
DHrxn = (0 + 33) - (143 + 90) = ??
drbob222 is correct . the answer is 200. DUh!!
It's -200. not 200