Thermochemistry | First Year Chemistry Past Papers MCQs | mosaicbro.com

Thermochemistry | First Year Chemistry Past Papers MCQs

7 of 38 questions (Page 5 of 6)

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29 The heat capacity of a substance is:
Correct Answer: A
Explanation: Heat capacity depends on amount of substance (extensive property).
30 The reaction with negative entropy change (ΔS < 0) is:
Correct Answer: D
Explanation: Freezing reduces disorder (ΔS < 0); others increase entropy.
31 The enthalpy of formation of an element in its standard state is:
Correct Answer: A
Explanation: By definition, ΔH°f = 0 for elements in their standard states.
32 The bond energy of H-H bond is:
Correct Answer: A
Explanation: H-H bond dissociation energy = 436 kJ/mol.
33 The heat of combustion is always:
Correct Answer: B
Explanation: Combustion releases energy (ΔH°c < 0).
34 The enthalpy change for the reaction N₂ + 3H₂ → 2NH₃ is called:
Correct Answer: A
Explanation: This is the standard heat of formation (ΔH°f) for ammonia.
35 The heat required to convert 1 mole of solid into liquid at its melting point is called:
Correct Answer: B
Explanation: Heat of fusion (ΔH_fus) is the energy for solid → liquid transition.
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