Question

1. Consider the reaction A(g) + B(g) ↔ C(g) + D(g) at 300°C. What is the equilibrium concentration of D if the initial concentrations are [A] = [B] = 1.25 x 10^-2 M and [C] = [D] = 3.50 x 10^-3 M? The value of the equilibrium constant for the reaction is 55.9 at 300°C.

1.41 x 10^-2 M

4.39 x 10^-2 M

8.34 x 10^-2 M

6.62 x 10^-2 M

5.76 x 10^-2 M

9.18 x 10^-3 M

2. The equilibrium constant for the following reaction is 4.66 x 10^-3 at 25°C. The system at equilibrium has [N₂O₄] = 0.208 M. What is [NO₂] in the equilibrium mixture?
N₂O₄(g) ↔ 2 NO₂(g)

4.51 x 10^-2 M
4.01 x 10^-2 M
5.79 x 10^-2 M
3.11 x 10^-2 M
2.21 x 10^-2 M
5.26 x 10^-2 M

3.The reaction 2 A(g) + B(g) ↔ C(g) + 3 D(g) has an equilibrium constant of 2.55 x 10^-3 at 85°C. If the initial concentrations are [A] = 1.50 M, [B] = 3.15 M, [C] = 0.0425 M, and [D] = 0.725 M, which of the following statements is true?

The system is not at equilibrium and will shift to the left to establish equilibrium.

The system is not at equilibrium and will shift to the right to establish equilibrium.

The system is at equilibrium and will not shift in either direction.

Cannot be predicted.

Answer 1

1. For the reaction

Initial concentration of reactants (A and B) are more than product (C and D) therefore reaction will proceed forward.

At equilibrium if x mole/L of A and B react to produce x moles of C and D

Final concentration of A= Final Concentration of B =

Final Concentration of C= Final Concentration of D=

Final concentration of

(2)

(3)

For the reaction

Intially

As

The system is at equilibrium and will not shift in either direction.