[Shipwreck]

Hi all,

First post on this forum. I would really appreciate some help with the following problem. I'm completely stuck! Thanks in advance!

0.050 mol NOBr is put into a flask with 1.0 L volume:

2 NOBr <=> 2NO + Br₂ (all gasses)

What is the equilibrium concentration K_p if the flask has a total pressure at equilibrium of 1.40 atm? Temperature = 300 K.

Answer: 0.025.

I don't understand how it's possible to calculate the partial pressures of the gasses at equilibrium. It seems that the question doesn't provide enough information...Would really appreciate your help, thanks!

[Borek]

What is the equilibrium concentration K_p

I suppose you mean "what is the equilibrium constant".

How does the pressure depend on the number of moles of the substance?

What does the stoichiometry of the reaction tell you about amounts of substances involved?

[Shipwreck]

I suppose you mean "what is the equilibrium constant".

Yep, that's exactly what I meant. My brain must have been off wandering as I was typing out the question 

Thanks so much for your help, Borek. I got it! I think I was overcomplicating the process. Your advice really helped simplify things. I somehow wasn't able to grasp the concept that the stoichiometric coefficients are always valid when it comes to determining the number of moles in a gaseous mixture. I think I confused myself by focusing too much on the nature of the equilibrium constant. Anyways, I really appreciate the guidance!