Solving Partial Pressures for H2 & Cl2 given K & PHCl

[jtruth914]

a) Determine K at 298K for the reaction H2(g) + Cl2(g) <---> 2HCl(g)
b) The equilibrium partial pressure of HCl is 1 bar. Determine the equilibrium partial pressures of H2 and Cl2.


This question was on my test. I got K= 3.2 x 10^-34 using dG*=-RTlnK when dG=0 at equilibrium. I'm having trouble determining the partial pressures. I know that Pj=(xj)(Ptot). I also know that K= (PHCl)^2/(PH2)(PCl2), but I still don't know how to determine the partial pressure just based off of PHCl=1 bar?

 

[Borek]

You are most likely to assume you started with HCl and all H₂ and Cl₂ are products of dissociation. This, plus stoichiometry, gives you all information you need to solve the problem.

 

[jtruth914]

I figured it out. thanks