- Joined
- Sep 25, 2009
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I ran into a problem on Topscore.
Using Hess's law what is the H rxn for 2C + O2 -> 2CO
C+O2 -> CO2 H = -393.7 kj/mol
CO + 1/2O2 -> CO2 H= -283.3 kj/mol
Answer: 2C + O2 -> 2CO; 2(-393.7kj) - (-(2(283.3kj))) = -220.8kj
I think Topscore has this WRONG. Correct me if I am wrong, but isn't Hess's law Hrxn = H sum(products) - H sum(reactants)?
2CO is the product and 2C + O2 is the reactants. So it should be:
2(283.3 kj) - 2(-393.7 kj) = 1354 kj
I flipped the negative on the CO because the reaction above show's it in the forward, however I am using it in reverse so the sign should be flipped.
Anyway, let me know if I am wrong. Just getting frustrated.
Using Hess's law what is the H rxn for 2C + O2 -> 2CO
C+O2 -> CO2 H = -393.7 kj/mol
CO + 1/2O2 -> CO2 H= -283.3 kj/mol
Answer: 2C + O2 -> 2CO; 2(-393.7kj) - (-(2(283.3kj))) = -220.8kj
I think Topscore has this WRONG. Correct me if I am wrong, but isn't Hess's law Hrxn = H sum(products) - H sum(reactants)?
2CO is the product and 2C + O2 is the reactants. So it should be:
2(283.3 kj) - 2(-393.7 kj) = 1354 kj
I flipped the negative on the CO because the reaction above show's it in the forward, however I am using it in reverse so the sign should be flipped.
Anyway, let me know if I am wrong. Just getting frustrated.