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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: kraver0 on November 29, 2012, 10:52:11 PM

Title: Equilibrium Constants Problem
Post by: kraver0 on November 29, 2012, 10:52:11 PM

I apologize for posting another question after posting the previous question 30 minutes ago... But this will be my last question.. I promise.

Here's the problem:

At a certain temperature the following have their equilibrium constants given below:

S(s) + O_2 (g) <---> SO_2 (g)          Kc1 = 4.2E+52
2S(s) + 3O_2 (g) <---> 2SO_3 (g)     Kc2 = 9.8E+128

Calculate the equilibrium constant Kc for the reaction below at the same temperature:

2SO_2 (g) + O_2 (g) <---> 2SO_3 (g)

Could someone please help me with this problem? Thanks.

Note:
I have absolute no idea on how to solve this. This problem was from a quiz, and pretty much three-fourths of the students in my lecture class got this problem wrong. Funny thing is that my TA (teacher assistant) doesn't even know how to solve this. I could've asked my professor, but he's always asking other students questions before I could get him my attention.

Title: Re: Equilibrium Constants Problem
Post by: curiouscat on November 30, 2012, 12:22:30 AM

What are the eqns. you know.

Title: Re: Equilibrium Constants Problem
Post by: Borek on November 30, 2012, 04:08:25 AM

As curiouscat hinted: write equations for all three K, then see if you can express Kc using Kc1 and Kc2.