Free energy question involving Kp and deltaG

[hahaha158]

Homework Statement

The following reaction takes place at standard conditions

4NH₃(g)+6NO(g)----->5N₂(g)+6H₂0

A)calculate reaction enthalpy and Gibbs reaction energy

B)Calculate Kp

Homework Equations

the table gives the following values for deltaG⁰_f[X]
NH₃(g)=-16.5 Kj/mol
NO(g)=87.6 KJ/mol
H₂0(g)=-228.6 KJ/mol

ln(Kp)=-deltaG/(RT)

The Attempt at a Solution

I finished part a) and found gibbs reaction energy to be -1815 KJ

For part b) i am unsure of what to enter for deltaG in the equation ln(Kp)=-deltaG/(RT). Do I use the reaction energy calculated from part a), deltaG for NH3, NO, or H20? Any help is appreciated, thanks!

 

[kaja]

you would use the standard DG found by this formula:
∑nΔG^oproducts - ΣmΔG^oreactants

 

[kaja]

-the n and m being the coefficients for each molecule

 

[Chestermiller]

Homework Statement

The following reaction takes place at standard conditions

4NH₃(g)+6NO(g)----->5N₂(g)+6H₂0

A)calculate reaction enthalpy and Gibbs reaction energy

B)Calculate Kp

Homework Equations

the table gives the following values for deltaG⁰_f[X]
NH₃(g)=-16.5 Kj/mol
NO(g)=87.6 KJ/mol
H₂0(g)=-228.6 KJ/mol

ln(Kp)=-deltaG/(RT)

The Attempt at a Solution

I finished part a) and found gibbs reaction energy to be -1815 KJ

For part b) i am unsure of what to enter for deltaG in the equation ln(Kp)=-deltaG/(RT). Do I use the reaction energy calculated from part a), deltaG for NH3, NO, or H20? Any help is appreciated, thanks!

You use the ΔG⁰ that you calculated in part a (I didn't check your arithmetic). (Also, that should not be a ΔG in the equation; it should be ΔG⁰). To get the standard reaction enthalpy, you need to know the standard heats of formation. Did they give you these?

Chet