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From the enthalpies of reaction... Calculate delta H for the reaction.?

2C(s)+O2(g) --> 2CO(g) delta H=-221.0 kJ

2C(s)+O2(g) + 4H2(g) --> 2CH3OH(g)

delta H = -402.4 kJ

Calculate delta H for the reaction

CO(g)+2H2(g) -->CH3OH(g)

2 Answers

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  • 7 years ago

    reverse first data equation and divide by 2 ---> this gets one CO on the left

    divide second data equation by 2 ---> gives us 2h2 and one CH3OH

    CO(g) --> C(s)+(1/2)O2(g) delta H=+110.5 kJ

    C(s)+(1/2)O2(g) + 2H2(g) --> CH3OH(g) delta H = -201.2 kJ

    Add the two equations together and the C and the 1/2O2 will cancel and you target equation is what is left.

    Add the two enthalpies for the final answer.

    More Hess' law problems:

    http://chemteam.info/Thermochem/HessLawIntro1.html

  • 7 years ago

    YOU ARE MY SAVIOR!!!

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