Equilibrium Partial Pressure Kp/Kc Question

[YeyFunNOT]

Homework Statement

At 100 ^o C K_c=.078 for the reaction SO₂Cl₂<-->SO₂ + Cl₂. In an equilibrium mixture the [SO₂CL₂]=.0108 M and [SO₂]=.052 M.

What is the partial pressure of Cl2 in the eq. mixture?

Homework Equations

K_p=K_c(RT)^$\Delta$n
P=RT/V

The Attempt at a Solution

I solve for K_p but I don't know how to find the partial pressure since neither the total pressure nor the volume is given.

 

[Borek]

Pressure can't be a function of the volume, which suggests in the end it will cancel out. Would it help to assume 1L total volume?

 

[YeyFunNOT]

I tried that, here's the work:
P=RT=(.0821)(373)=30.6233 atm

Moles is M*L so all of the moles equal the concentration. Total number of moles is .0108+.052+.0162 (moles of Cl₂)=.079 total moles. So the pCl₂= .0162/.079*30.6233=6.27 atm.

The book says 5 atm so where am I going wrong?

 

[Borek]

I tried that, here's the work:
P=RT=(.0821)(373)=30.6233 atm

List assumptions used to calculate this number.

But I don't see how the final answer can be 5 atm. Are you sure you have not missed a decimal point?

 

[YeyFunNOT]

List assumptions used to calculate this number.

But I don't see how the final answer can be 5 atm. Are you sure you have not missed a decimal point?

I used the ideal gas law, PV=nRT rearranged to solve for P. (I did this in another problem in the same set to get overall pressure). I just set the volume as 1 L.

I checked all the numbers and the answer in the book and everything seems correct. :S

 

[Borek]

I used the ideal gas law, PV=nRT rearranged to solve for P. (I did this in another problem in the same set to get overall pressure). I just set the volume as 1 L.

P=nRT/V, what have you used for n?

 

[YeyFunNOT]

Thanks for the help, I did indeed misplace a decimal xD.