12 questions · 12 marks · ≈ 12 min
Which are correct for the reaction shown?
CH3COOH + KOH → CH3COO−K++ 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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Which is the correctly labelled reaction profile for an exothermic reaction?
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The energy profile for a reaction is shown.
What is the minimum energy needed for this reaction to occur?
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X
Y
X − Y
X + Y
Which equation does not represent a standard enthalpy change of atomisation?
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Mg (s) → Mg (g)
Cl2 (g) → 2Cl (g)
1⁄2O2 (g) → O (g)
Hg (l) → Hg (g)
Which equation represents the standard enthalpy change of atomisation, ΔatH, of bromine?
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1⁄2 Br2 (l) → Br (g)
Br2 (l) → 2Br (g)
1⁄2 Br2 (g) → Br (g)
Br2 (g) → 2Br (g)
The equation for a reaction is
2C (s) + O2 (g) → 2CO (g)
Which is the correct symbol for the enthalpy change for this reaction?
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ΔatH
ΔcH
ΔfH
ΔrH
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]
Choose your answer
–12.3 kJ mol−1
–16.6 kJ mol−1
–63.8 kJ mol−1
–16600 kJ mol−1
The equation for the complete combustion of methanal is shown.
Some bond enthalpy data are shown.
| Bond | Bond enthalpy / kJ mol−1 |
|---|---|
| C—H | 413 |
| OO | 498 |
| CO in CO2 | 805 |
| O—H | 464 |
What is the CO bond enthalpy in methanal?
Choose your answer
623 kJ mol−1
678 kJ mol−1
805 kJ mol−1
1036 kJ mol−1
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?
Choose your answer
methane
ethane
propane
butane
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?
Choose your answer
+113.2
+1.2
−1.2
−113.2
The reaction profile for an endothermic reaction is shown.
What is the activation energy of the reverse reaction?
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–70 kJ mol–1
+70 kJ mol–1
+80 kJ mol–1
+230 kJ mol–1
The enthalpy changes of combustion, ΔcH, are given below.
| Substance | ΔcH / kJ mol–1 |
|---|---|
| C (s) | –394 |
| H2 (g) | –286 |
| CH3OH (l) | –726 |
What is the enthalpy change of formation, ΔfH, of methanol, CH3OH (l)?
Choose your answer
–240 kJ mol–1
+240 kJ mol–1
–966 kJ mol–1
–1406 kJ mol–1