The enthalpy change for the transition of liquid water to steam is 40.8 kJ mol -1 at 373 K. Calculate the entropy of vaporisation of water.

Question

The enthalpy change for the transition of liquid water to steam is 40.8 kJ mol -1 at 373 K. Calculate the entropy of vaporisation of water. (A) 109.4 JK -1 mol -1 (B) 10.94 JK -1 mol -1 (C) 1.094 JK -1 mol -1 (D) 1009.4 JK -1 mol -1

Tardigrade Admin · Accepted Answer

Δ S text vap =(Δ H text vap / T ) ∵ Δ H text vap =40.8 kJ mol -1, T =373 K Δ S text vap =(40.8 × 103/373)=109.4 JK -1 mol -1

Q. The enthalpy change for the transition of liquid water to steam is $40.8 k J m o l^{- 1}$ at $373 K$ . Calculate the entropy of vaporisation of water.

$109.4 J K^{- 1} m o l^{- 1}$

$10.94 J K^{- 1} m o l^{- 1}$

$1.094 J K^{- 1} m o l^{- 1}$

$1009.4 J K^{- 1} m o l^{- 1}$

$Δ S_{vap} = \frac{Δ H _{vap}}{T}$
$∵ Δ H_{vap} = 40.8 k J m o l^{- 1}, T = 373 K$
$Δ S_{vap} = \frac{40.8 \times 1 0 ^{3}}{373} = 109.4 J K^{- 1} m o l^{- 1}$

Q. The enthalpy change for the transition of liquid water to steam is 40.8kJmol−1 at 373K. Calculate the entropy of vaporisation of water.

109.4JK−1mol−1

10.94JK−1mol−1

1.094JK−1mol−1

1009.4JK−1mol−1