# Question 6

Consider the balanced equation below for a hypothetical reaction that takes place in a sealed 2 dm3
container at 300 K.
2P(g) + Q2(g) ⇌ 2PQ(g)

6.1 Define the term chemical equilibrium. (2)

6.2 The amount of each substance present in the equilibrium mixture at 300 K is shown in the table below.

The temperature of the container is now increased to 350 K.
When a NEW equilibrium is established, it is found that 1,2 mol P(g) is present in the container.

6.2.1 Is the heat of the reaction (∆H) POSITIVE or NEGATIVE? (1)

6.2.2 Use Le Chatelier’s principle to explain the answer to QUESTION 6.2.1. (3)

6.2.3 Calculate the equilibrium constant at 350 K. (8)

6.2.4 How will the equilibrium constant calculated in QUESTION 6.2.3 be affected when the volume of the container is decreased at constant temperature?
Choose from INCREASES, DECREASES or REMAINS THE SAME.
Give a reason for the answer. (2)

6.3 More Q2(g) is now added to the reaction mixture at constant temperature.
How will EACH of the following be affected? Choose from INCREASES, DECREASES or REMAINS THE SAME.

6.3.1 The yield of PQ(g) (1)

6.3.2 Number of moles of P(g) (1)