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in this lab, you will determine the vapour pressure (p) of water at var…

Question

in this lab, you will determine the vapour pressure (p) of water at various temperatures and use this data to find its enthalpy of vaporization ($\delta_{vap}h$).
more generally, for an unknown liquid: if a plot of $\ln p$ vs. $1/t$ gives a slope of -3105 k, what is its $\delta_{vap}h$ in kj/mol? do not worry about how realistic the value is. assume $r = 8.314 j mol^{-1}k^{-1}$.

Explanation:

Step1: Recall the Clausius - Clapeyron equation

The Clausius - Clapeyron equation in the form of a linear equation \(y = mx + c\) for \(\ln P\) vs. \(\frac{1}{T}\) is \(\ln P=-\frac{\Delta_{vap}H}{R}\times\frac{1}{T}+C\). Here, the slope \(m =-\frac{\Delta_{vap}H}{R}\).

Step2: Solve for \(\Delta_{vap}H\)

Given \(m=- 3105\space K\) and \(R = 8.314\space J\space mol^{-1}\space K^{-1}\). From \(m =-\frac{\Delta_{vap}H}{R}\), we can solve for \(\Delta_{vap}H\). Rearranging the formula gives \(\Delta_{vap}H=-m\times R\).
Substitute the values: \(\Delta_{vap}H=-(-3105\space K)\times8.314\space J\space mol^{-1}\space K^{-1}\)

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Answer:

\(25.8\space kJ/mol\)