1. Which statement about bonding is correct?

A. Bond breaking is endothermic and requires energy.

B. Bond breaking is endothermic and releases energy.

C. Bond making is exothermic and requires energy.

D. Bond making is endothermic and releases energy.

(Total 1 mark)

2. Which is correct about energy changes during bond breaking and bond
formation?

Bond breaking Bond formation

A. exothermic and ∆H positive endothermic and ∆H
negative
B. exothermic and ∆H endothermic and ∆H
negative positive
C. endothermic and ∆H exothermic and ∆H
positive negative
D. endothermic and ∆H exothermic and ∆H positive
negative
(Total 1 mark)

3. What is the energy, in kJ, released when 1.00 mol of carbon monoxide is
burned according to the following equation?

2CO(g) + O2(g) → 2CO2(g) ΔHo = –564 kJ

A. 141

B. 282

C. 564

D. 1128
(Total 1 mark)

IB Questionbank Chemistry 1
4. Which of the following reactions are exothermic?

I. CH4 + 2O2 → CO2 + 2H2O

II. NaOH + HCl → NaCl + H2O

III. Br2 → 2Br

A. I and II only

B. I and III only

C. II and III only

D. I, II and III
(Total 1 mark)

5. Which combination is correct for a chemical reaction that absorbs heat from the
surroundings?

ΔH at constant
Type of reaction
pressure
A. Exothermic Positive
B. Exothermic Negative
C. Endothermic Positive
D. Endothermic Negative
(Total 1 mark)

6. How much energy, in joules, is required to increase the temperature of 2.0 g of

aluminium from 25 to 30 °C? (Specific heat of Al = 0.90 J g–1 K–1).

A. 0.36

B. 4.5

C. 9.0

D. 54
(Total 1 mark)

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IB Questionbank Chemistry 3
7. The specific heat of iron is 0.450 J g–1 K–1. What is the energy, in J, needed to
increase the temperature of 50.0 g of iron by 20.0 K?

A. 9.00

B. 22.5

C. 45.0

D. 450
(Total 1 mark)

8. A pure aluminium block with a mass of 10 g is heated so that its temperature

increases from 20 °C to 50 °C . The specific heat capacity of aluminium is 8.99
× 10–1 J g–1 K–1. Which expression gives the heat energy change in kJ?

A. 10 × 8.99 × 10–1 × 303

B. 10 × 8.99 × 10–1 × 30

10  8.99  10 1  303
C. 1000

10  8.99 10 1  30
D. 1000
(Total 1 mark)

IB Questionbank Chemistry 4
9. The data below are from an experiment to measure the enthalpy change for the
reaction of aqueous copper(II) sulfate, CuSO4(aq) and zinc, Zn(s).

Cu2+(aq) + Zn(s) → Cu(s) + Zn2+(aq)

50.0 cm3 of 1.00 mol dm–3 copper(II) sulfate solution was placed in a
polystyrene cup and zinc powder was added after 100 seconds. The
temperature-time data was taken from a data-logging software program. The
table shows the initial 23 readings.

A straight line has been drawn through some of the data points. The equation
for this line is given by the data logging software as

T = –0.050t + 78.0

where T is the Temperature at time t.

IB Questionbank Chemistry 5
 (a) The heat produced by the reaction can be calculated from the temperature
change, ΔT, using the expression below.

Heat change = Volume of CuSO4(aq) × Specific heat capacity of H2O × ∆T

Describe two assumptions made in using this expression to calculate heat

changes.

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(2)

(b) (i) Use the data presented by the data logging software to deduce the
temperature change, ∆T, which would have occurred if the reaction
had taken place instantaneously with no heat loss.

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(2)

(ii) State the assumption made in part (b)(i).

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(1)

(iii) Calculate the heat, in kJ, produced during the reaction using the
expression given in part (a).

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(1)

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 (c) The colour of the solution changed from blue to colourless. Deduce the
amount, in moles, of zinc which reacted in the polystyrene cup.

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(1)

(d) Calculate the enthalpy change, in kJ mol–1, for this reaction.

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(1)
(Total 8 marks)

10. Methanol is made in large quantities as it is used in the production of polymers

and in fuels.
The enthalpy of combustion of methanol can be determined theoretically or
experimentally.

1
CH3OH(l) + 1 2 O2(g) → CO2(g) + 2H2O(g)

(a) Using the information from Table 10 of the Data Booklet, determine the
theoretical enthalpy of combustion of methanol.

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(3)

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 (b) The enthalpy of combustion of methanol can also be determined
experimentally in a school laboratory. A burner containing methanol was
weighed and used to heat water in a test tube as illustrated below.

The following data were collected.

Initial mass of burner and

80.557
methanol / g
Final mass of burner and methanol /
80.034
g
Mass of water in test tube / g 20.000
Initial temperature of water / °C 21.5
Final temperature of water / °C 26.4

(i) Calculate the amount, in mol, of methanol burned.

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(2)

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 (ii) Calculate the heat absorbed, in kJ, by the water.

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(3)

(iii) Determine the enthalpy change, in kJ mol–1, for the combustion of 1

mole of methanol.

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(2)

(c) The Data Booklet value for the enthalpy of combustion of methanol is –
726 kJ mol–1.
Suggest why this value differs from the values calculated in parts (a) and
(b).

(i) Part (a)

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 .............
(1)

(ii) Part (b)

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(1)
(Total 12 marks)

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11. Consider the following reactions.

1
Cu2O(s) + 2 O2(g) → 2CuO(s) ∆HO = –144 kJ
Cu2O(s) → Cu(s) + CuO(s) ∆HO = +11 kJ

What is the value of ∆HO, in kJ, for this reaction?

1
Cu(s) + 2 O2(g) → CuO(s)

A. –144 + 11

B. +144 – 11

C. –144 – 11

D. +144 + 11
(Total 1 mark)

IB Questionbank Chemistry 14
12. The standard enthalpy change of three combustion reactions is given below in
kJ.

2C2H6(g) + 7O2(g) → 4CO2(g) + 6H2O(l)∆HO = –3120

2H2(g) + O2(g) → 2H2O(l) ∆HO = –572
C2H4(g) + 3O2(g) → 2CO2(g) + 2H2O(l) ΔHO = –1411

Based on the above information, calculate the standard change in enthalpy,

∆HO, for the following reaction.

C2H6(g) → C2H4(g) + H2(g)

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(Total 4 marks)

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13. Use the average bond enthalpies below to calculate the enthalpy change, in kJ,
for the following reaction.

H2(g) + I2(g) → 2HI(g)

Bond Bond energy / kJ mol–1

H–H 440
I–I 150
H–I 300

A. +290

B. +10

C. –10

D. –290
(Total 1 mark)

14. Propane can be formed by the hydrogenation of propene.

CH3CH=CH2(g) + H2(g) → CH3CH2CH3(g)

(i) State the conditions necessary for the hydrogenation reaction to occur.

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(2)

(ii) Enthalpy changes can be determined using average bond enthalpies.

Define the term average bond enthalpy.

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IB Questionbank Chemistry 16
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(2)

(iii) Determine a value for the hydrogenation of propene using information

from Table 10 of the Data Booklet.

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(2)

(iv) Explain why the enthalpy of hydrogenation of propene is an exothermic

process.

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(1)
(Total 7 marks)

15. Which equation best represents the bond enthalpy of HCl?

A. HCl(g) → H+(g) + Cl–(g)

B. HCl(g) → H(g) + Cl(g)

1 1
C. HCl(g) → 2 H2(g) + 2 Cl2(g)

D. 2HCl(g) → H2(g) + Cl2(g)

(Total 1 mark)

IB Questionbank Chemistry 17
16. Hydrazine is a valuable rocket fuel.

The equation for the reaction between hydrazine and oxygen is given below.

N2H4(g) + O2(g) → N2(g) + 2H2O(g)

Use the bond enthalpy values from Table 10 of the Data Booklet to determine
the enthalpy change for this reaction.
(Total 3 marks)

1
H2(g) + 2

IB Questionbank Chemistry 18