Gaokao Exam Gaokao Chemistry: Chemical Equilibrium and Reactions 1

Question 1

For the equilibrium N₂(g) + 3H₂(g) ⇌ 2NH₃(g), increasing pressure at constant temperature will:

Accepted Answer

Shift the equilibrium toward products (NH₃)

Answer

Shift the equilibrium toward reactants

Answer

Have no effect on the equilibrium position

Answer

Decrease the equilibrium constant

Question 2

The equilibrium constant expression for 2SO₂(g) + O₂(g) ⇌ 2SO₃(g) is:

Accepted Answer

K = [SO₃]²/([SO₂]²[O₂])

Answer

K = [SO₂]²[O₂]/[SO₃]²

Answer

K = [SO₃]/([SO₂][O₂])

Answer

K = [SO₃]²[SO₂]²[O₂]

Question 3

At 25°C, for the reaction H₂(g) + I₂(g) ⇌ 2HI(g), K = 50. If [H₂] = [I₂] = 0.1 M and [HI] = 0.5 M initially, the reaction quotient Q is:

Accepted Answer

25

Answer

50

Answer

100

Answer

5

Question 4

For an endothermic reaction at equilibrium, increasing temperature will:

Accepted Answer

Increase K and shift equilibrium toward products

Answer

Decrease K and shift equilibrium toward products

Answer

Increase K and shift equilibrium toward reactants

Answer

Leave K unchanged

Question 5

Adding a catalyst to a reaction at equilibrium:

Accepted Answer

Speeds up both forward and reverse reactions equally, leaving equilibrium position unchanged

Answer

Shifts equilibrium toward products only

Answer

Shifts equilibrium toward reactants only

Answer

Changes the equilibrium constant

Question 6

For the reaction A(g) + B(g) ⇌ C(g) + D(g) with K = 4, if [A] = [B] = 1 M and [C] = [D] = x at equilibrium, then x =

Accepted Answer

2 M

Answer

4 M

Answer

0.5 M

Answer

1 M

Question 7

The degree of dissociation of a weak acid increases when:

Accepted Answer

The solution is diluted with water

Answer

A common ion is added to the solution

Answer

The solution is concentrated

Answer

The temperature is decreased