Gce Model Questions Vol1 2022 Chemistry Question 18

Practice objective / multiple choice question 18 from the 2022 Gce Model Questions Vol1 Chemistry examination.

Gce Model Questions Vol1 2022 Chemistry Objective / Multiple Choice Medium Difficulty
Question 18 GCE_MODEL_QUESTIONS_VOL1 • 2022 • CHEMISTRY • objective

The liquid-vapour equilibrium of a substance obeys the Clausius-Clapeyron relation with a constant enthalpy of vaporisation over the temperature range considered. At 350 K the vapour pressure is 0.80 atm and at 370 K it is 1.20 atm. Its solid-vapour equilibrium also follows the same relation with a constant enthalpy of sublimation. At 300 K the sublimation pressure is 0.10 atm and at 320 K it is 0.25 atm. Using R = 8.314 J mol\(^{-1}\) K\(^{-1}\), calculate (i) the enthalpy of vaporisation ΔHvap, (ii) the enthalpy of sublimation ΔHsub, both in kJ mol\(^{-1}\), and (iii) the enthalpy of fusion ΔHfus.

Answer Options

A. ΔHvap ≈ 24.5 kJ mol⁻¹; ΔHsub ≈ 38.2 kJ mol⁻¹; ΔHfus ≈ 13.5 kJ mol⁻¹
B. ΔHvap ≈ 22.3 kJ mol⁻¹; ΔHsub ≈ 40.1 kJ mol⁻¹; ΔHfus ≈ 12.0 kJ mol⁻¹
C. ΔHvap ≈ 19.0 kJ mol⁻¹; ΔHsub ≈ 34.0 kJ mol⁻¹; ΔHfus ≈ 15.2 kJ mol⁻¹
Correct Answer D. ΔHvap ≈ 21.8 kJ mol⁻¹; ΔHsub ≈ 36.6 kJ mol⁻¹; ΔHfus ≈ 14.8 kJ mol⁻¹
Correct Answer
D
Correct Option:
ΔHvap ≈ 21.8 kJ mol⁻¹; ΔHsub ≈ 36.6 kJ mol⁻¹; ΔHfus ≈ 14.8 kJ mol⁻¹

About This Question

This is Gce Model Questions Vol1 2022 Chemistry Question 18. It is one of the objective questions from the 2022 Gce Model Questions Vol1 Chemistry examination.

Difficulty level: Medium .

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