RevisionDojo

R1.1 Measuring enthalpy change - IB Questionbank | RevisionDojo

Practice R1.1 Measuring enthalpy change 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

SLPaper 2

Ammonia is formed by the Haber process:

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

The diagram below shows the energy profile of this reaction.

State what is meant by the term activation energy.

[1]

Identify whether the reaction is exothermic or endothermic and justify your answer using the diagram.

[2]

Suggest one reason why a high temperature is required for this reaction to proceed at a practical rate.

[1]

Explain how the use of a catalyst would affect the energy profile diagram.

[2]

The Haber process is a reversible reaction. State and explain one condition used in industry to increase the yield of ammonia.

[2]

Question 2

HLPaper 2

A student investigates the enthalpy change when potassium chloride ( ${KCl}$ ) dissolves in water. They dissolve $2.00\ \mathrm{g}$ of ${KCl(s)}$ in $100.0\ \mathrm{g}$ of water and observe the temperature drop from $25.0^\circ\mathrm{C}$ to $22.5^\circ\mathrm{C}$ . The specific heat capacity of water is $4.18\ \mathrm{J\ g^{-1}\ ^\circ C^{-1}}$ and the molar mass of ${KCl}$ is $74.55\ \mathrm{g\ mol^{-1}}$ .

Calculate the heat absorbed by the water using $Q = mc\Delta T$ .

[2]

Calculate the number of moles of ${KCl}$ dissolved.

[1]

Determine the enthalpy change of solution for ${KCl}$ in $\mathrm{kJ\ mol^{-1}}$ . Include the sign.

[2]

State the physical meaning of the sign of your answer to Part 3.

[1]

Discuss why the dissolution of an ionic solid like ${KCl}$ can be spontaneous even when it is endothermic.

[2]

Question 3

HLPaper 1A

Which equation represents the standard enthalpy of atomization of bromine, $Br_2$ ?

Question 4

SLPaper 1A

What is the heat change, in kJ, when 100.0 g of aluminium is heated from 19.0 °C to 32.0 °C?

Specific heat capacity of aluminium: 0.90 $J g^{−1} K^{−1}$

Question 5

SLPaper 1A

Which change of state is exothermic?

Question 6

SL & HLPaper 1A

A student burns ethanol in a spirit burner to heat 200 g of water. The water temperature increases by $15.0^\circ \text{C}$ . What is the heat absorbed by the water? (Use $c = 4.18\ \text{J g}^{-1} \text{K}^{-1}$ )

Question 7

SLPaper 1A

The enthalpy of combustion of ethanol is determined by heating a known mass of tap water in a glass beaker with a flame of burning ethanol.

Which will lead to the greatest error in the final result?

Question 8

HLPaper 1A

Which expression gives the mass, in g , of ethanol required to produce 683.5 kJ of heat upon complete combustion?

$(M_r \text{ for ethanol} = 46.0, \Delta H_c^\ominus = -1367 \text{ kJ mol}^{-1})$

Question 9

HLPaper 1A

Which equation represents the bond enthalpy for H–Br in hydrogen bromide?

Question 10

SL & HLPaper 1A

Which of the following methods is commonly used to measure the enthalpy change of a reaction?

R1.1 Measuring enthalpy change Questionbank