[4evrastudent]

I'm asked to solve a problem given this chemical equation:

2SO_(g)  2SO_2(g) + O_2(g)

I'm given K = 1.32 at 900.15 K and asked to find the constant at 828.15 K.

I'm not really sure how to go about this, but I'm thinking that I would plug in the constant and temperature into the equation ΔG = -R*T*lnK_eq

Then I'm thinking I would take the ΔG value and and plug it into the above equation with 828.15 K as the T value.

I've tried this and it doesn't seem to get me to the right answer. Could someone point me in the right direction? Do I have to go back and use ΔG = ΔH - TΔS

Thanks!

EDIT: My notation was messed up.

[Corribus]

Look up the Van't Hoff equation.

http://en.wikipedia.org/wiki/Van%27T_Hoff_Equation

(Using your approach won't work because ΔG is not invariant to temperature.)

EDIT: By the way, your equation doesn't seem to be balanced.

[4evrastudent]

Look up the Van't Hoff equation.

http://en.wikipedia.org/wiki/Van%27T_Hoff_Equation

(Using your approach won't work because ΔG is not invariant to temperature.)

EDIT: By the way, your equation doesn't seem to be balanced.

Thank you, that chemical equation is not correct. The correct one is:
2SO_3(g)  2SO_2(g) + O_2(g)

Just to clarify, the equation I want is this one: ΔG = -R * T * lnK_eq

[Corribus]

Well, you really need ΔH.  This is not given?  Are you allowed to look up this value?
Otherwise I'm not seeing at first glance how to solve the problem.