Part 1 2.A mixture initially contains A, B, and C in the following concentration
ID: 902135 • Letter: P
Question
Part 1
2.A mixture initially contains A, B, and C in the following concentrations: [A] = 0.350M , [B] = 0.600 M , and [C] = 0.300 M . The following reaction occurs and equilibrium is established:
A+2BC
At equilibrium, [A] = 0.220 M and [C] = 0.430 M . Calculate the value of the equilibrium constant, Kc.
Express your answer numerically.
Part 2
Ammonium bisulfide, NH4HS, forms ammonia, NH3, and hydrogen sulfide, H2S, through the reaction
NH4HS(s)NH3(g)+H2S(g)
This reaction has a Kp value of 0.120 at 25 C.
What is the initial pressure of H2S(g) in the flask?
Express your answer numerically in atmospheres.
Explanation / Answer
Given, Initially
[A] = 0.35 M, [B] = 0.6 M, [C] = 0.3 M
The reaction is,
A + 2B ----------> C
0.35-X.. 0.6-2X..............0.3+X
At equilibrium
[C] = 0.3 + X = 0.43 M
=> X = 0.13 M
=> [B] = 0.6 - 2X = 0.6 - 0.26 = 0.34 M
Equilibrium Constant, Kc = [C] / [A] [B]^2
=> Kc = 0.43 / 0.22 x 0.34^2 = 16.91
Part 2
NH4HS(s)NH3(g)+H2S(g)
......................p............p
Kp = P (NH3) x P(H2S)
where,
P (NH3) = Partial Pressure of NH3
P (H2S) = Partial Pressure of H2S
Kp = 0.12 = p x p = p^2
=> p = 0.364 atm = Initial Pressure of H2S (g)