Dear Aynaz: your analysis is correct. I wonder why you have doubts here, and the reason might be that you left energy (enthalpy) out of the equation.

You might also want to investigate the Clapeyron Equation, which follows from one of Maxwell's relationships, which reveals that the latent heat is related to the saturation pressure. There is an article here> https://en.wikipedia.org/wiki/Clausius%E2%80%93Clapeyron_relation

Thank you Dr. Dudley J Benton

Thank you dear Bas Mannaerts

Can you help me how to calculate the enthalpy of vaporization at a constant temperature (boiling temperature of the solvent)?

Dr. Dudley J Benton, I have a problem

There are 2 temperatures in the Clausius-Clapeyron relation but actually enthalpy of vaporation occurs at a constant temperature(boiling temperature)

The enthalpy of vaporization does indeed occur at constant temperature. There is a temperature and the change in temperature with pressure in the Clapeyron equation, which can be easily measured in the laboratory. In some cases, it is easier to measure each term in the Clapeyron equation than it is to isolate and insulate a container fitted with a weighted piston or some other means of assuring the pressure is constant, then add or remove heat so as to evaporate or condense the substance within. Bear in mind that the change in density from liquid to vapor may span orders of magnitude, which may present significant problems if you are trying to maintain constant pressure and no leakage. In a cylinder, for example, the newly exposed tube wall as the piston expands during evaporation will participate in the heat transfer, making it difficult to accurately quantify the heat transferred to the liquid alone.

Dear Aynaz: the enthalpies of evaporation are found in tables, but can also be found for individual liquids (solvents) in wikidata. More accurate would be to calculate the enthalpy of formation at boiling-point for both the liquid and the vapor and take the difference.

Thank you so much, Dr. Dudley J Benton

I appreciate it

Dear Bas Mannaerts, a solvent is a combination of several different substances

A solvent is a substance that dissolves a solute, resulting in a solution. (Wikipedia) A mixture of solvents does not have a proper boiling point, so the above analysis would not apply.

Enthalpy of vaporisation tables, i.e. latent heat, for many fluids are available in many textbooks, e.g, Perry, Chemical Engineers Handbook. Boiling a liquid is supplying the sensible heat to raise the liquid to boiling point, then a lot more energy to convert the liquid to vapour. Is your solvent very non-standard?

Yes Jack Broughton

It is an uncertain combination

what you stated is generally correct. Just be aware that, depending on the level of accuracy you need, and especially when in the gas phase, your material properties may not be constant with temperature or pressure. Additionally, if you can get estimates of heat loss from your vessel at different temperatures you will have a better idea of where measurement error might creep into your analyisis.

Thank you Dr. Nicholas Robert Jankowski for answering, I appreciate it.

1. Experimental measurement: The most accurate way to determine the enthalpy of vaporization is through experimental measurements using calorimetry. This involves measuring the heat transfer during the phase transition from liquid to vapor. By measuring the temperature change and known masses of the substance, the enthalpy of vaporization can be calculated using the equation Q = m × ΔH, where Q is the heat transferred, m is the mass, and ΔH is the enthalpy of vaporization.

2. Trouton's rule: Trouton's rule is an empirical rule that provides an estimate of the enthalpy of vaporization based on the boiling point of a substance. According to Trouton's rule, the enthalpy of vaporization (ΔHvap) is approximately a constant value of around 88 J/mol·K. It can be expressed as ΔHvap ≈ R × Tb, where R is the ideal gas constant and Tb is the boiling point in Kelvin.

3. Group contribution methods: Group contribution methods are used to estimate the enthalpy of vaporization based on the molecular structure of the substance. These methods assign specific contributions to different functional groups or molecular fragments and sum them up to estimate the overall enthalpy of vaporization.

4. Semi-empirical correlations: Various semi-empirical correlations exist to estimate the enthalpy of vaporization based on molecular properties, such as molecular weight, critical temperature, or critical pressure. These correlations are typically based on regression analysis of experimental data and provide reasonable estimates for a wide range of substances.

It is great!

Thank you dear Abdulsalam Abdu