Equilibrium (Questions from Kognity)

At a specific temperature, the equilibrium constants were deduced for the following reactions.

                [1] 2A(g) + B₂(g) ⇌ 2C₂(g)                 K_c1 = 72.4

                [2] D₂(g) + 2E(g) ⇌ C₂(g)                   K_c2 = 43.1

Calculate the equilibrium constant at the same temperature and pressure for the following equilibrium reaction. State your answer to three significant figures. 

                [3] A(g) + ½B₂(g) ⇌ D₂(g) + 2E(g)

The following equilibrium reaction has an equilibrium constant K_c1.

                A + 2B ⇌ C + 2D

Identify which of the following would represent the equilibrium constant K_c2, for the following equilibrium reaction at the same temperature.

                ½C + D ⇌ ½A + B 

The equilibrium reaction of N₂O₄ (colourless gas) and NO₂ (brown gas) is shown below:

N₂O₄ (g) (colourless gas) ⇌ 2NO₂ (g) (brown)

At room temperature, a sealed glass tube of the equilibrium mixture appears to be a dark brown.

When this sealed tube is placed into an ice bath, the gas within the tube starts to change colour and, when equilibrium is reestablished, it is light yellow.

What information does this change provide about the equilibrium mixture in the ice bath?

• Forward reaction is endothermic; K_c decreases when mixture is placed in the ice.

• Forward reaction is exothermic; K_c decreases when mixture is placed in the ice.

• Forward reaction is endothermic; K_c increases when mixture is placed in the ice.

• Forward reaction is exothermic; K_c increases when mixture is placed in the ice.

Consider the data for the following reaction.

2NO₂ (g) (brown) ⇌ N₂O₄(g) (colourless)

ΔH = ?

The sign of ΔH for this reaction is __________

and the trial with the darker shade of brown is trial

___________.

• negative; 1

• negative, 2

• positive, 1

• positive, 2

Which of the following explains why a catalyst does not affect the position of equilibrium?

• A catalyst increases the rate of the forward and reverse reactions equally

• A catalyst has no effect on the rate of the forward or the reverse reactions

• A catalyst decreases the rate of the forward and reverse reactions equally

• A catalyst provides an alternative reaction pathway with a lower activation energy