Problem: The molar enthalpy of vaporization (∆H) of water is 40.7 kJ/mol. What is the vapor pressure of water at 40.°C (R=8.314J/K mol)?A) 11.5 torrB) 311 torrC) 3.58 torrD) 38.6 torrE) 61.4 torr

FREE Expert Solution

We’re being asked to determine the vapor pressure of water at 40°C. We’re given the heat of vaporization of water ΔHvap = 40.7 kJ/mol. 


We can use the Clausius-Clapeyron Equation to solve for the vapor pressure of water.


ln P2P1=-HvapR[1T2-1T1]


where:

P1 = vapor pressure at T1

P2 = vapor pressure at T2

ΔHvap = heat of vaporization (in J/mol)

R = gas constant (8.314 J/mol•K)

T1 and T2 = temperature (in K).


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Problem Details

The molar enthalpy of vaporization (∆H) of water is 40.7 kJ/mol. What is the vapor pressure of water at 40.°C (R=8.314J/K mol)?

A) 11.5 torr

B) 311 torr

C) 3.58 torr

D) 38.6 torr

E) 61.4 torr

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