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.
O3(g)+NO(g)-->O2(g)+NO2(g)
Standard enthalpy of formation in kJ/mol:
O3(g) 143
NO(g) 90
NO2(g) 33
I am sure this isn't a hard problem, but I can't really remember how to do it.
5 answers
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) = ??
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
3 answers