At high temperature, 0.500 mol of HBR was placed in a 1.00L container where it decomposed to give the equilibrium:
2HBr <==> H2 + Br2
At equilibrium, the [Br2] is 0.0855 mol/L. What is the value of the equilibrium constant?
My work:
..2HBr <==> H2 + Br2
I 0.500M...---..---
C -0.171..-0.0855..+0.0855
E 0.500-0.171..-0.855..0.0855
Keq = 0.0855/(0.500-0.171)^2(-0.0855)
= 0.0855/-0.009254605
= -9.24
I'm not even sure if I'm doing this right, please help!
You went wrong on the C step and E step.
(HBr) = mols/L = 0.5/1 L = 0.5M which you hvave correctly.
..............2HBr <==> H2 + Br2
I..............0.5.......0....0
C..............-2x.......x....x
E............0.5-2x......x....x
The problem states that (Br2) is 0.0855 (which is x); therefore, (H2) must be 0.0855 and (HBr) must be 0.5-(2*0.0855)
Plug those values into Keq expression and calculate Keq.
Note that mols don't add up; remember mols are not conserved in a reaction. Grams yes but not mols.
Close but no cigar.
You didn't square the (0.5-0.171) which makes the 0.329 squared also. I have 0.0675
ooh, thank you!
To solve this problem, we need to use the concept of equilibrium constant (K). The equilibrium constant is a measure of the extent to which a reaction proceeds to form products at a given temperature.
In the given equation:
2HBr <==> H2 + Br2
The equilibrium constant expression (Kc) is given by:
Kc = [H2][Br2] / [HBr]^2
Given that the equilibrium concentration of Br2 ([Br2]) is 0.0855 mol/L, we need to find the equilibrium concentration of HBr ([HBr]).
From your provided work, it seems you did the initial and change calculations correctly, but made mistakes when calculating the equilibrium concentrations.
To correct your work, let's re-evaluate the equilibrium concentrations:
Initial concentration of HBr: 0.500 mol/L
Change in concentration of HBr: -0.171 mol/L (from the balanced equation)
Equilibrium concentration of HBr: 0.500 - 0.171 = 0.329 mol/L
Now, we can substitute the equilibrium concentrations into the equilibrium constant expression:
Kc = [H2][Br2] / [HBr]^2
= (0.0855 mol/L) / (0.329 mol/L)^2
Calculating this expression, we get:
Kc ≈ 0.725
Thus, the value of the equilibrium constant (Kc) is approximately 0.725.
Keq = (0.0855)^2/0.5-0.171
= 0.00731025/0.329 = 0.0222
Keq = 0.0222
is this correct?