PYQ Vault
EbooksTutor

Melting or boiling point from the enthalpy and entropy of the phase change

This type of question, asked 2 times: 15 Apr 2023, 9 Apr 2024. All 2 questions below, oldest first.

Try each one first, then open its answer.

  1. Question 1

    15 Apr 2023

    60
    30.4 kJ30.4\text{ }kJ of heat is required to melt one mole of sodium chloride and the entropy change at the melting point is 28.4 J K−1 mol−128.4\text{ }J{\text{ }K}^{- 1}{\text{ }mol}^{- 1} at 1 atm1\text{ }atm. The melting point of sodium chloride is_____ K (Nearest Integer)

  2. Question 2

    9 Apr 2024

    150
    When ΔHvap =30 kJ/mol\Delta H_{\text{vap~}}= 30\text{ }kJ/mol and ΔSvap =75 J mol−1 K−1\Delta S_{\text{vap~}}= 75\text{ }J{\text{ }mol}^{- 1}{\text{ }K}^{- 1}, then the temperature of vapour, at one atmosphere is ____ KK.