Equilibrium - exam practice

Equal amounts of W and X are mixed and allowed to reach equilibrium.

W + X ⇌ Y + Z

The value of the equilibrium constant is 4.85. At equilibrium, the mixture will contain

One mole of phosphorus(V) chloride, PCl₅, is heated to 600 K in a sealed flask of volume 1 dm³.

Equilibrium is established and measurements are taken.

PCl_5(g) ⇌ PCl_3(g) + Cl_2(g)

The experiment is repeated with one mole of phosphorus(V) chloride heated to 600 K in a sealed flask of volume 2 dm³.

How will the measurements vary?

Which statement about the effect of a catalyst on a reversible reaction is correct?

Chloroethene, CH₂=CHCl, is prepared in the presence of a solid catalyst using the equilibrium reaction below.

CH₂ClCH₂Cl_(g) ⇌ CH₂=CHCl_(g) + HCl_(g) ΔH = +51 kJ mol^-1

Which change would result in an increased equilibrium yield of chloroethene?

Hydrogen gas can be produced as shown below.

CH_4(g) + H₂O_(g) ⇌ CO_(g) + 3H_2(g) ΔH = +206 kJ mol^-1

Which conditions produce the greatest equilibrium yield of hydrogen?

A pale brown mixture of NO₂ and N₂O₄ is allowed to reach equilibrium in a sealed gas syringe according to the following equation.

2NO_2(g) ⇌ N₂O_4(g)

When the plunger is pushed further into the syringe the pressure increases and the mixture becomes paler in colour.

When the syringe is placed in a hot oven the mixture becomes darker in colour.

Which of the following statements is correct?

Which statement is not always correct for a reaction at equilibrium?

reactants ⇌ products

The equilibrium for the reaction between hydrogen gas and an oxide of iron is:

Fe₃O_4(s) + 4H_2(g) ⇌ 3Fe_(s) + 4H₂O_(g)

The K_c expression for this equilibrium is...