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    Thermodynamics : Heats of Formation

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    For the reaction CH4 (g) + N2 (g) + 164 kJ 6 HCN(g) + NH3 (g) at 25degrees C and 1 atm of pressure
    ÄGo = 159 kJ. Calculate ÄSo at 25degrees C.

    ÄHfo for CH4 (g) = -74.77 kJ/mol and ÄHfo for
    NH3 (g) = -46.09 kJ/mol. What is ÄHfo for HCN(g) ?

    © BrainMass Inc. brainmass.com December 24, 2021, 8:05 pm ad1c9bdddf
    https://brainmass.com/chemistry/energetics-and-thermodynamics/thermodynamics-heats-formation-246826

    SOLUTION This solution is FREE courtesy of BrainMass!

    For the reaction CH4 (g) + N2 (g) + 164 kJ 6 HCN(g) + NH3 (g) at 25degrees C and 1 atm of pressure
    ÄGo = 159 kJ. Calculate ÄSo at 25degrees C.

    Looking at your reaction, you know the reaction required 164 kJ of heat. This is your ΔH value. You know ΔG = ΔH - TΔS, so you can plug in the given values to solve:

    ÄHfo for CH4 (g) = -74.77 kJ/mol and ÄHfo for
    NH3 (g) = -46.09 kJ/mol. What is ÄHfo for HCN(g) ?

    To find the heat of formation, you need to find the products minus the reactants. Remember the heat of formation of N2 is zero because it is in its natural state:

    The heat of formation of HCN is 130 kJ/mol.

    This content was COPIED from BrainMass.com - View the original, and get the already-completed solution here!

    © BrainMass Inc. brainmass.com December 24, 2021, 8:05 pm ad1c9bdddf>
    https://brainmass.com/chemistry/energetics-and-thermodynamics/thermodynamics-heats-formation-246826

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