17.1 The Equilibrium Law

Question 1

Marks: 1

The Haber process is a key step in the manufacture of fertilisers:

N₂ (g) + 3H₂ (g) $⇌$ 2NH₃ (g) ΔH = -ve

Which is correct about the effect of increasing temperature for this reaction?

	Effect on equilibrium position	Effect on K_c
A.	Shifts left	No change
B.	Shifts right	No change
C.	Shifts right	Increase
D.	Shifts left	Decrease

Key Concepts

Explaining Le Châtelier’s Principle

Question 2

Marks: 1

Which equation represents a reaction where the number of moles alone can not be used to calculate the value of K_c?

CH₃CH₂OH (aq) + CH₃COOH (aq) $⇌$ CH₃CH₂OCOCH₃(aq) + H₂O (l)
H₂ (g) + I₂ (g) $⇌$ 2HI (g)
2SO₂ (g) + O₂ (g) $⇌$ 2SO₃ (g)
N₂ (g) + O₂ (g) $⇌$ 2NO (g)

Key Concepts

Equilibrium Problems

Question 3

Marks: 1

When 0.20 mol NO, 0.08 mol H₂ and 0.10 mol of H₂O are placed in a 1.0 dm³ flask, the following equilibrium is established:

2NO (g) + 2H₂ (g) $⇌$ N₂ (g) + 2H₂O (g)

At equilibrium, the concentration of H₂ (g) was found to be 0.02 mol dm^-3.

What is the correct calculation to work out K_c?

K_c = $\frac{{[0.14]}^{2} {[0.02]}^{2}}{{[0.03]}^{} {[0.16]}^{2}}$
K_c = $\frac{[0.03] {[0.16]}^{2}}{{[0.14]}^{2} {[0.02]}^{2}}$
K_c = $\frac{[0.03] {[0.06]}^{2}}{{[0.06]}^{2} {[0.06]}^{2}}$
K_c = $\frac{[0.06] {[0.16]}^{2}}{{[0.14]}^{2} {[0.04]}^{2}}$

Key Concepts

Equilibrium Problems

Question 4

Marks: 1

Nitrogen dioxide can form a dimer that can also break back down again as part of a reversible reaction:

N₂O₄ (g) $⇌$ NO₂ (g) ΔH = +ve

The reaction reaches an equilibrium at temperature T, where K_c = 1

What is true for a higher temperature, T₂?

	K_c value	ΔG^θ value
A.	Increases	Increases
B.	Decreases	Increases
C.	Decreases	Decreases
D.	Increases	Decreases

Key Concepts

Gibbs Free Energy & the Equilibrium Constant

Question 5

Marks: 1

Which would be the correct way to plot a graph and then calculate ΔG^θ from experimental data of K_c and temperature values?

ΔG^θ = -RT ln K

	y-axis	x-axis	ΔG^θ =
A.	1 / T	ln K	-R x gradient
B.	ln K	1 / T	-R x gradient
C.	ln K	1 / T	R / gradient
D.	1 / T	ln K	R / gradient

Key Concepts

Free Energy & Equilibrium Calculations

DP IB Chemistry: HL

Topic Questions

17.1 The Equilibrium Law

Question 1

Key Concepts

Question 2

Key Concepts

Question 3

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Question 4

Key Concepts

Question 5

Key Concepts

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