Consider the following reaction and associated equilibrium constant: aA(g)bB(g),
ID: 949256 • Letter: C
Question
Consider the following reaction and associated equilibrium constant: aA(g)bB(g), Kc = 2.7. 1).Find the equilibrium concentrations of A and B for a=1 and b=1. Assume that the initial concentration of A is 1.0 M and that no B is present at the beginning of the reaction. 2)Find the equilibrium concentrations of A and B for a=2 and b=2. Assume that the initial concentration of A is 1.0 M and that no B is present at the beginning of the reaction. 3)Find the equilibrium concentrations of A and B for a = 1 and b = 2. Assume that the initial concentration of A is 1.0 M and that no B is present at the beginning of the reaction.
Explanation / Answer
1)
A ----> B
1-X ....X
Kc = [B] / [A]
=> 2.7 = X / (1-X)
=> X = 0.73 M
=> [A] eq.= 1 - X = 0.27 M and [B] eq. = X = 0.73 M
2)
2 A ----> 2 B
1 - 2X ....2X
Kc = [B]2 / [A]2
=> 2.7 = (2X)2 / (1-2X)2
=> X = 0.311 M
=> [A] eq.= 1 - 2X = 0.378 M and [B] eq. = 2X = 0.622 M
3)
A ----> 2 B
1-X .... 2X
Kc = [B]2 / [A]
=> 2.7 = (2X)2 / (1-X)
=> X = 0.551 M
=> [A] eq.= 1 - X = 0.449 M and [B] eq. = 2X = 1.102 M