Clausius-Clapeyron Equation Video Lessons

Concept:

# Problem: What is the vapor pressure of mercury at 25°C if its enthalpy of vaporization is 59.1 kJ/mol? Note that the normal boiling point of mercury is 357°C.

###### FREE Expert Solution

For this problem, we can use the Clausius-Clapeyron Equation:

$\overline{){\mathbf{ln}}\mathbf{\left(}\frac{{\mathbf{P}}_{\mathbf{2}}}{{\mathbf{P}}_{\mathbf{1}}}\mathbf{\right)}{\mathbf{=}}{\mathbf{-}}\frac{\mathbf{∆}{\mathbf{H}}_{\mathbf{vap}}}{\mathbf{R}}\mathbf{\left[}\frac{\mathbf{1}}{{\mathbf{T}}_{\mathbf{2}}}\mathbf{-}\frac{\mathbf{1}}{{\mathbf{T}}_{\mathbf{1}}}\mathbf{\right]}}$

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

What is the vapor pressure of mercury at 25°C if its enthalpy of vaporization is 59.1 kJ/mol? Note that the normal boiling point of mercury is 357°C.