Problem: The vapor pressure of ammonia at several different temperatures is shown below. Temperature (K)  Pressure (torr)20065.3210134.3220255.7230456.0235597.0Determine the normal boiling point of ammonia.

FREE Expert Solution

We’re being asked to determine the normal boiling point of ammonia. We’re given the vapor pressure at different temperatures.

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

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

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
The vapor pressure of ammonia at several different temperatures is shown below.

 Temperature (K) Pressure (torr) 200 65.3 210 134.3 220 255.7 230 456.0 235 597.0

Determine the normal boiling point of ammonia.