Equilibrium Question

Question

0.450 mol of hydrogen bromide gas decomposes in a 0.75 L container according to the reaction below:

2 HBr_(g)  ↔ H_2(g) +  Br_2(l)

At equilibrium the concentration of H_2(g) was found to be 0.132 mol/L. The value of the equilibrium constant Kc is a.bc

Answer 1

This problem is a little different from all the others you posted, so I thought I'd give you a little guidance, so you can do others that are similar.

The balanced equation is

2HBr(g) <==> H₂(g) + Br₂(l) and you are given the initial [HBr] as 0.450 mol/0.75 L = 0.600 M. You are also provided with the equilibrium [H₂] as 0.132 M. You are asked to find the equilibrium constant, Kc.

From my previous explanation, Kc = products / reactants with each raised to the power of the coefficient in the balanced equation.

Set up an ICE table to find equilibrium [HBr].

2HBr(g) <==> H₂(g) + Br₂(l)

0.600 M...........0...........0.........Initial

-2x.................+x..........+x........Change

0.6-2x..............x............x.........Equilibrium

x = 0.132 M as given in the problem

[HBr] @ equilibrium = 0.600 - (2 x 0.132) = 0.600 - 0.336 = 0.264 M

Kc = [H₂] / [HBr]² (note: Br₂ is not included as it is a liquid)

Kc = (0.132) / (0.264)² = 0.132 / 0.0697

Kc = 1.89

Answer 2

Hi Jinjuu M.,

That's six questions, all on the same material area, all asked at the same time. One would have been sufficient to get the technique explained; six is misusing Wyzant to do your assignment.

-- Cheers, --Mr. d.