enthalpy change

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Darwin420
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enthalpy change

Post by Darwin420 » Wed Dec 03, 2008 11:19 pm

Consider the thermochemical equations given below.
C2H4(g) + 3 O2(g) → 2 CO2(g) + 2 H2O(l) ΔH° = −1411 kJ (per mol C2H4)
C(s) + 3 H2 (g) + ½ O2(g) → C2H5OH(l) ΔH° = −278 kJ (per mol C)
C2H4(g) + H2O(l) → C2H5OH (l) ΔH° = −44 kJ (per mol C2H4)
What is ΔH° for the following reaction? All the answers below are for the
combustion of one mole of C2H5OH. (1 mark)
C2H5OH(l) + 3 O2(g) → 2 CO2(g) + 3 H2O(l)


Hey guys, again another question. I am trying to studying for my exam and this was one of the questions I got on my test that I messed up.

I usually have no problems what so ever how to do this BUT what do I do with the H2? Like how do I eliminate that out of the equation to get the final equation?

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mith
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Post by mith » Thu Dec 04, 2008 12:45 am

fyi, the standard enthalpy for creation of element is 0.
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MichaelXY
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Post by MichaelXY » Fri Dec 05, 2008 4:21 am

This powerpoint slide gives an explanation for your problem.

http://www.chalkbored.com/lessons/chemistry-12/5

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