Enthelpy of vaporization of hexane

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The discussion focuses on estimating the enthalpy of vaporization (ΔHvap) for hexane, given its normal boiling point of 69.0°C. A user initially calculated ΔHvap as 34 kJ/mol using the Clausius-Clapeyron equation but found the expected answer to be 29.1 kJ/mol. The approximation's limitations are acknowledged, particularly the assumption of temperature independence and ideal gas behavior. Suggestions for improving accuracy include using reference points closer to the boiling point and pressure conditions. The conversation emphasizes the nature of estimates in thermodynamic calculations.
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Homework Statement


The normal boiling point of hexane is 69.0°C. Estimate (a) its enthalpy
of vaporization

The Attempt at a Solution


In order to solve for ΔHvap in the Clausius-Clapeyron equation I need a reference T and p point. I extracted it from the triple point (T=178K and p=1,23Pa).
I solve and I get 34kJ/mol, while the answer is 29,1kJ/mol. What I've done wrong?

Thanks!
 
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The Clausius-Clapeyron equation is just an approximation, because it is assumed in deriving it that the enthalpy of vaporization is temperature independent and that the gas phase behaves as an ideal gas. Like it's said in the question, you are only expected to give an estimate, anyway.
 
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So how would you do to get a more accurate result? One option is to get a (T,p) point closer to the desired 69ºC and 1bar, but if this is not available...?
 

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