Edexcel International A Level Chemistry

Topic Questions

2.1 Energetics

11 mark

Which are correct for the reaction shown?

CH3COOH + KOH → CH3COOK++ H2O        ΔH = –55.8 kJ mol−1

      Type of reaction Type of enthalpy change
  A endothermic formation
  B endothermic neutralisation
  C exothermic formation
  D exothermic neutralisation

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21 mark

Which is the correctly labelled reaction profile for an exothermic reaction?

q1-paper-2-june-2021-edexcel-ial-chemistry

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31 mark

The energy profile for a reaction is shown.

q1-paper-2-jan-2021-edexcel-ial-chemistry

What is the minimum energy needed for this reaction to occur?

  • X

  • Y

  • X − Y

  • X + Y

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41 mark

Which equation does not represent a standard enthalpy change of atomisation?

  • Mg (s) → Mg (g)

  • Cl2 (g) → 2Cl (g)

  • 1⁄2O2 (g) → O (g)

  • Hg (l) → Hg (g)

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51 mark

Which equation represents the standard enthalpy change of atomisation, ΔatH, of bromine?

  • 1⁄2 Br2 (l) → Br (g)

  • Br2 (l) → 2Br (g)

  • 1⁄2 Br2 (g) → Br (g)

  • Br2 (g) → 2Br (g)

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11 mark

The equation for a reaction is

2C (s) + O2 (g) → 2CO (g)

Which is the correct symbol for the enthalpy change for this reaction?

  • ΔatH

  • ΔcH

  • ΔfH

  • ΔrH

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2
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1 mark

5.20 g of sodium hydrogencarbonate is added to an excess of acid.

The temperature increases and the energy change is calculated to be 1030 J.

What is the enthalpy change per mole of sodium hydrogencarbonate?

[Mr NaHCO3 = 84.0]

  • –12.3 kJ mol−1

  • –16.6 kJ mol−1

  • –63.8 kJ mol−1

  • –16600 kJ mol−1

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3
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1 mark

The equation for the complete combustion of methanal is shown.

q4-paper-2-jan-2022-edexcel-ial-chemistry

Some bond enthalpy data are shown.

Bond Bond enthalpy / kJ mol−1
C—H 413
OequalsO 498
CequalsO in CO2 805
O—H 464


What is the CequalsO bond enthalpy in methanal?

  • 623 kJ mol−1

  • 678 kJ mol−1

  • 805 kJ mol−1

  • 1036 kJ mol−1

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4
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1 mark

The table shows the amount of energy released per gram when some alkanes are burned in excess oxygen under standard conditions.

Alkane Energy released / kJ g−1
methane 55.6
ethane 52.0
propane 50.4
butane 49.6


Which alkane has a standard enthalpy change of combustion of −2877 kJ mol−1?

  • methane

  • ethane

  • propane

  • butane

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5
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1 mark

The enthalpy changes for two reactions are shown.

H+ (aq) + OH(aq) → H2O (l)                    ΔrH = −57.2 kJ mol−1

CH3COOH (aq) + OH(aq) → CH3COO(aq) + H2O (l)     ΔrH = −56.0 kJ mol−1

What is the enthalpy change for the dissociation of CH3COOH (aq) into CH3COO(aq) and H+ (aq) ions, in kJ mol−1?

  • +113.2

  • +1.2

  • −1.2

  • −113.2

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