How do you find [delta]Hvap?
with
ln(p1/p2)=deltaHvap/R x (1/T2-1/T2)
To find the molar enthalpy of vaporization (ΔHvap) for a substance, you can follow these general steps:
1. Collect the necessary data: You will need the initial and final states of the substance, particularly its initial and final temperatures and pressures.
2. Determine the change in enthalpy: Calculate the change in enthalpy (ΔH) using the equation ΔH = q, where q represents the heat absorbed or released during the phase transition.
3. Apply the formula: Use the molar enthalpy formula, ΔHvap = ΔH / n, where n represents the number of moles of substance undergoing vaporization.
4. Convert units if necessary: Ensure that the units are consistent throughout the calculations. For example, if the heat (q) is given in joules, divide it by 1000 to convert it to kilojoules before using it in the formula.
Keep in mind that the data required may vary depending on the specific experiment or scenario.