Question

The following are thermodynamic data for isopropanol, an alcohol commonly known as rubbing alcohol: ΔH°f = -317.0 kJ mol-1 ΔH°comb = -127.2 kJ mol-1 ΔH fus = 5.3 kJ mol-1 ΔH vap = 44.0 kJ mol-1 S°m = 180.6 J mol-1 K-1 ΔS fus = 28.6 J mol-1 K-1 ΔS vap = 123.9 J mol-1 K-1 (a) At the boiling point, liquid and vapor phase of isopropanol are at equilibrium (ΔG = 0). Choose appropriate thermodynamic data to calculate the boiling point of isopropanol. (b) Compare your calculated value with the value reported in the literature (or online).

3. (2 pts) The following are thermodynamic data for isopropanol, an alcohol commonly known as rubbing alcohol: AH = -317.0 kJ mol-1 AHⓇcomb = -127.2 kJ mol-1 AH fus = 5.3 kJ mol-1 AH vap = 44.0 kJ mol-1 Sºm = 180.6 J mol K-1 AS fus = 28.6 J mol-1 K-1 AS vap = 123.9 J mol-1 K-1 (a) At the boiling point, liquid and vapor phase of isopropanol are at equilibrium (AG = 0). Choose appropriate thermodynamic data to calculate the boiling point of isopropanol. (b) Compare your calculated value with the value reported in the literature (or online)

Answer 1

A) T_{​​​​BP} =∆H°_vap/∆S°_vap

= 44.0×1000/123.9

= 355 K => 82.1 °c

B) Value reported from literature = 82.5 °C

So, values are approximately equal as calculated and online data