Problem: For ethanol, ΔvapH° = 43.5 kJ mol-1. (i) Calculate q, w, ΔH and ΔU when 1.75 mol C2H5OH (l) is vaporised at 260 K at constant external pressure. (ii) Explain whether the vaporisation of ethanol is exothermic or endothermic. (iii) If methanol has a ΔvapH° = 37.4 kJ mol-1, would you expect methanol or ethanol to have greater intermolecular forces? Give a reason for your answer.

FREE Expert Solution

We are given with the Heat of Vaporization of ethanol, ΔvapH° = 43.5 kJ mol-1 and asked several questions.


Part A. We are asked to calculate q, wΔH, and ΔU when 1.75 mol C2H5OH (l) is vaporized at 260 K at constant external pressure. 

Part B. We are asked to explain whether the vaporization of ethanol is exothermic or endothermic

Part C. We are asked to explain which between methanol and ethanol, from the ΔvapH° of both, would have greater intermolecular forces


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Problem Details

For ethanol, ΔvapH° = 43.5 kJ mol-1

(i) Calculate q, w, ΔH and ΔU when 1.75 mol C2H5OH (l) is vaporised at 260 K at constant external pressure. 

(ii) Explain whether the vaporisation of ethanol is exothermic or endothermic. 

(iii) If methanol has a ΔvapH° = 37.4 kJ mol-1, would you expect methanol or ethanol to have greater intermolecular forces? Give a reason for your answer.

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