Energetics I | Edexcel A-Level Chemistry (9CH0)
Energetics I
- 39 questions
- 2 subtopics
- Paper 1: advanced inorganic and physical chemistry
- Paper 1 and Paper 3
Covers the standard enthalpy definitions, measuring an enthalpy change by calorimetry, and calculating one from Hess cycles or from bond enthalpies..
It covers enthalpy changes, standard definitions and calorimetry and hess's law and bond enthalpies.
Sample questions from Energetics I
Answer each one closed book first, then open the answer.
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Enthalpy changes, standard definitions and calorimetry
Define the standard enthalpy change of reaction.
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The enthalpy change when the molar amounts shown in the equation react under standard conditions, with all substances in their standard states. -
Enthalpy changes, standard definitions and calorimetry
What value of the specific heat capacity of water is normally used?
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4.18 J per gram per kelvin. -
Hess's law and bond enthalpies
Define bond enthalpy.
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The energy required to break one mole of a specified covalent bond with all species in the gaseous state. -
Hess's law and bond enthalpies
Which enthalpy change is found indirectly in Core Practical 8?
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The enthalpy change for the thermal decomposition of potassium hydrogencarbonate: 2KHCO₃(s) → K₂CO₃(s) + CO₂(g) + H₂O(l).
The 2 subtopics
One subtopic is one session. Work down the list.
| Subtopic | What it covers | Questions |
|---|---|---|
| Enthalpy changes, standard definitions and calorimetry | Enthalpy change and standard conditions, exothermic and endothermic signs and enthalpy level diagrams, the standard enthalpy changes of reaction, formation, combustion and neutralisation, using Q = mcΔT to find ΔH in kJ mol⁻¹, and the heat losses and assumptions that limit calorimetry. | 19 |
| Hess's law and bond enthalpies | Hess's law and cycles built from enthalpies of formation or combustion, bond and mean bond enthalpies and why calculations from them are approximate, and Core Practical 8 finding the enthalpy change for decomposing potassium hydrogencarbonate indirectly. | 20 |
How the guide is worked
Answering a question from memory stores it far better than reading the answer again. The guide runs that as a fixed procedure on one subtopic at a time, about twenty minutes a session.
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Step 1 · Closed book
Cover the answers. Work through one subtopic and write down what you can. Leave blanks where you have nothing.
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Step 2 · Open book
Go back to the top. Read each printed answer and write it out in full, including the ones you had right.
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Step 3 · Closed book again
Same questions, same order, from memory. The gap between pass one and pass three is the session result.
Read the full method, the return schedule and the research behind it.
Nearby topics
Edexcel A-Level Chemistry Active Recall Guide
Every topic, not just this one. 1,534 questions with their answers.