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Topic: Hess Law Different Coefficients  (Read 2848 times)

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Offline CLiz

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Hess Law Different Coefficients
« on: February 14, 2011, 04:15:08 PM »
Can someone please help me?!!?!?

I have been working on this problem for hours and I am not getting it!!!

Usinh Hess's Law calculate the value of delta H value for the following reaction;

FeO + CO ----Fe +CO2

Using the three equations;

Fe(2)O + 3CO ----- 2Fe + 3CO2

3Fe(2)O(3) + CO ----- 2Fe(3)O(4) + CO2

Fe(3)O(4) + CO -----3FeO + CO2

Thanks!!!!!


Offline Nobby

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Re: Hess Law Different Coefficients
« Reply #1 on: February 15, 2011, 06:45:29 AM »
All equations not existent

Fe(2)O + 3CO ----- 2Fe + 3CO2

3Fe(2)O(3) + CO ----- 2Fe(3)O(4) + CO2

Fe(3)O(4) + CO -----3FeO + CO2

Iron can only be +II or +III

What means there is only

FeO + CO => Fe + CO2

Fe2O3 + 3 CO => 2 Fe + 3 CO2

and Fe3O4 + 4 CO => 3 Fe + 4 CO2

So what you can do is convert equation 2 in  CO => 2/3 Fe +  CO2 - 1/3 Fe2O3

Substitute the CO in Equation 3

Fe3O4 - 8/3 Fe - 4 CO2 + 4/3 Fe2O3 => 3 Fe + 4 CO2

Fe3O4 => 17/3 Fe + 8 CO2 + 4/3 Fe2O3

Fe3O4 = FeO x Fe2O3

FeO => 17/3 Fe + 8 CO2 + 1/3 Fe2O3


« Last Edit: February 15, 2011, 07:15:54 AM by Nobby »

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