Entropy Video Lessons

Concept

# Problem: Calculate the change in entropy that occurs in the system when 30.5 g of acetone (C3H6O) vaporizes from a liquid to a gas at its normal boiling point (56.1 ˚C).

###### FREE Expert Solution

$\overline{){\mathbf{∆}}{\mathbf{S}}{\mathbf{=}}\frac{\mathbf{∆}\mathbf{H}}{\mathbf{T}}}$

ΔS = entropy, J/mol•K
ΔH = enthalpy, J
T = temperature, K

$\overline{){\mathbf{∆}}{{\mathbf{S}}}_{{\mathbf{vap}}}{\mathbf{=}}\frac{\mathbf{∆}{\mathbf{H}}_{\mathbf{vap}}}{{\mathbf{T}}_{\mathbf{b}}}}$

ΔHvap of acetone = 31.3 kJ/mol    →  convert from kJ to J: 1 kJ = 103 J
***can be found in books or online

Tb = 56.1°C + 273.15 = 329.25 K

Calculate ΔSvap:

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###### Problem Details

Calculate the change in entropy that occurs in the system when 30.5 g of acetone (C3H6O) vaporizes from a liquid to a gas at its normal boiling point (56.1 ˚C).