## Homework Problem 11.3 for 6th Edition

Helen Zhao 1F
Posts: 31
Joined: Fri Sep 28, 2018 12:20 am

### Homework Problem 11.3 for 6th Edition

For Question 11.3 from the 6th edition textbook, the question asks to find the equilibrium constant of the following equations. According to the solution manual, the equilibrium constant involves the partial pressure of the molecules. Is it partial pressure because we do not know the molarity of the gases?

Neil Hsu 2A
Posts: 61
Joined: Fri Sep 28, 2018 12:16 am

### Re: Homework Problem 11.3 for 6th Edition

For gas-phase molecules, you can use either partial pressures or concentrations depending on what they give you. Additionally, you can convert between partial pressure and concentration using the ideal gas law PV=nRT, where n/V is concentration, so P = (conc)RT or (conc) = P/RT. I'm not sure which question you're talking about since I have the seventh edition, but just know that both partial pressures and concentrations are acceptable involving gas-phase molecules.

Laura Gong 3H
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### Re: Homework Problem 11.3 for 6th Edition

I think you can either Kc or Kp as long as you follow the conventions for either. So if you were to write Kc expressions, remembering to put the brackets symbolizing concentration around the products and reactants or for Kp expressions, using P (representing partial pressure) and the subscript of either the product or reactant.

Hai-Lin Yeh 1J
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### Re: Homework Problem 11.3 for 6th Edition

So, does that mean if you wrote it like this:
Kc = [C2H4Cl2]^2 [H2O]^2 / [C2H4]^2 [O2] [HCl]^4
is this still correct because you wouldn't have to write P (partial pressure)?