R1.4 Entropy and spontaneity (HL) - IB Questionbank | RevisionDojo

R1.1 Measuring enthalpy change

R1.2 Energy cycles in reactions

R1.3 Energy from fuels

R1.4 Entropy and spontaneity (HL)

R1.4 Entropy and spontaneity (HL) Questionbank

Practice R1.4 Entropy and spontaneity (HL) with authentic IB Chemistry exam questions for both SL and HL students. This question bank mirrors Paper 1A, 1B, 2 structure, covering key topics like atomic structure, chemical reactions, and organic chemistry. Get instant solutions, detailed explanations, and build exam confidence with questions in the style of IB examiners.

Paper

Level

Question 1

HLPaper 1A

Which of the following physical states has the highest entropy at a given temperature?

Question 2

HLPaper 1A

For a reaction where $\Delta H > 0$ and $\Delta S < 0$ , what is the sign of $\Delta G$ at all temperatures?

Question 3

HLPaper 1A

A reaction has $\Delta H^\ominus = +100\,\text{kJ}\,\text{mol}^{-1}$ and $\Delta S^\ominus = +250\,\text{J}\,\text{mol}^{-1}\,\text{K}^{-1}$ .

At what minimum temperature (in K) will the reaction become spontaneous?

Question 4

HLPaper 2

Melting ice is a spontaneous process at room temperature.

Predict the sign of $\Delta S$ for the melting of ice.

[1]

State one reason for this prediction.

[1]

Explain in terms of particle arrangement why entropy increases during melting.

[2]

Question 5

HLPaper 2

Reaction: $\text{H}_2(\text{g}) + \text{I}_2(\text{g}) \to 2\text{HI}(\text{g})$

$\Delta H^\circ = +26\ \text{kJ mol}^{-1}$

$\Delta S^\circ = +164\ \text{J mol}^{-1}\ \text{K}^{-1}$

Calculate $\Delta G^\circ$ at $298\ \text{K}$ .

[2]

Calculate the temperature where $\Delta G^\circ = 0$ .

[2]

Question 6

HLPaper 1A

Which of the following statements is true if $\Delta G^\ominus < 0$ ?

Question 7

HLPaper 2

Ammonia synthesis: $N_2(g) + 3H_2(g) \to 2NH_3(g)$

$\Delta H^\circ = -92\ \mathrm{kJ\ mol^{-1}}$ $\Delta S^\circ = -198\ \mathrm{J\ mol^{-1}\ K^{-1}}$

Calculations should be performed using the given values.

Calculate $\Delta G^\circ$ at $298\ \mathrm{K}$ .

[3]

State whether the reaction is spontaneous at this temperature.

[1]

Predict the effect of increasing temperature on the spontaneity of the reaction.

[1]

Question 8

HLPaper 1A

Which change results in the largest negative value of $\Delta S$ ?

Question 9

HLPaper 1A

The combustion of glucose is exothermic and occurs according to the following equation:

$\text{C}_6\text{H}_{12}\text{O}_6(\text{s}) + 6\text{O}_2(\text{g}) \rightarrow 6\text{CO}_2(\text{g}) + 6\text{H}_2\text{O}(\text{g})$

Which is correct for this reaction?

	$\Delta H^\ominus$	$\Delta S^\ominus$	Spontaneous / non-spontaneous
A	Negative	Positive	Spontaneous
B	Negative	Positive	Non-spontaneous
C	Positive	Negative	Spontaneous
D	Positive	Positive	Non-spontaneous

Question 10

HLPaper 1A

What is the sign of $\Delta S$ for the reaction below?

$\text{N}_2(\text{g}) + 3\text{H}_2(\text{g}) \rightarrow 2\text{NH}_3(\text{g})$

Paper

Level

Question 1

HLPaper 1A

Which of the following physical states has the highest entropy at a given temperature?

Question 2

HLPaper 1A

For a reaction where $\Delta H > 0$ and $\Delta S < 0$ , what is the sign of $\Delta G$ at all temperatures?

Question 3

HLPaper 1A

A reaction has $\Delta H^\ominus = +100\,\text{kJ}\,\text{mol}^{-1}$ and $\Delta S^\ominus = +250\,\text{J}\,\text{mol}^{-1}\,\text{K}^{-1}$ .

At what minimum temperature (in K) will the reaction become spontaneous?

Question 4

HLPaper 2

Melting ice is a spontaneous process at room temperature.

Predict the sign of $\Delta S$ for the melting of ice.

[1]

State one reason for this prediction.

[1]

Explain in terms of particle arrangement why entropy increases during melting.

[2]

Question 5

HLPaper 2

Reaction: $\text{H}_2(\text{g}) + \text{I}_2(\text{g}) \to 2\text{HI}(\text{g})$

$\Delta H^\circ = +26\ \text{kJ mol}^{-1}$

$\Delta S^\circ = +164\ \text{J mol}^{-1}\ \text{K}^{-1}$

Calculate $\Delta G^\circ$ at $298\ \text{K}$ .

[2]

Calculate the temperature where $\Delta G^\circ = 0$ .

[2]

Question 6

HLPaper 1A

Which of the following statements is true if $\Delta G^\ominus < 0$ ?

Question 7

HLPaper 2

Ammonia synthesis: $N_2(g) + 3H_2(g) \to 2NH_3(g)$

$\Delta H^\circ = -92\ \mathrm{kJ\ mol^{-1}}$ $\Delta S^\circ = -198\ \mathrm{J\ mol^{-1}\ K^{-1}}$

Calculations should be performed using the given values.

Calculate $\Delta G^\circ$ at $298\ \mathrm{K}$ .

[3]

State whether the reaction is spontaneous at this temperature.

[1]

Predict the effect of increasing temperature on the spontaneity of the reaction.

[1]

Question 8

HLPaper 1A

Which change results in the largest negative value of $\Delta S$ ?

Question 9

HLPaper 1A

The combustion of glucose is exothermic and occurs according to the following equation:

$\text{C}_6\text{H}_{12}\text{O}_6(\text{s}) + 6\text{O}_2(\text{g}) \rightarrow 6\text{CO}_2(\text{g}) + 6\text{H}_2\text{O}(\text{g})$

Which is correct for this reaction?

	$\Delta H^\ominus$	$\Delta S^\ominus$	Spontaneous / non-spontaneous
A	Negative	Positive	Spontaneous
B	Negative	Positive	Non-spontaneous
C	Positive	Negative	Spontaneous
D	Positive	Positive	Non-spontaneous

Question 10

HLPaper 1A

What is the sign of $\Delta S$ for the reaction below?

$\text{N}_2(\text{g}) + 3\text{H}_2(\text{g}) \rightarrow 2\text{NH}_3(\text{g})$