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Topic: Hess's Law  (Read 2740 times)

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Offline enantiomorph

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Hess's Law
« on: November 03, 2006, 03:47:08 AM »
Hi, I was working on some questions involving thermochemistry.  I came across a problem involving heats and enthalpy that I don't know how to solve.  I was wondering if anyone may please give me a hand with this.  Thank You.

Question:  How much heat is evolved when 1.022x10 moles of CO2(g) is produced from the combustion of CO(g).
2CO(g) + O2(g) -> 2CO2(g)
The enthalpies of formations are:
CO(g) -110.5 kJ/mol
O2(g) 0.0
CO2(g) -393.5 kJ/mol
H2O(l) -286.0 kJ/mol

I tried the problem and I applied the formula for findng enthalpies with the enthalpies of formation [i.e. (Sum of # moles x enthalpy of formation for products) - (Sum of # moles x enthalpy of formation for reactants)]
I got a value of -566 kJ/2mol so -283 kJ/mol, then I multiplied 10.22 mol to -283 kJ/mol, but the answer was wrong according to my book.  If someone can help, that will be great.  Thanks alot.

Offline AWK

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Re: Hess's Law
« Reply #1 on: November 03, 2006, 09:04:58 AM »
AWK

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