Question

Calculate the value of 's' when 1.00 mol of CH₃OH(i) is vaporized at 64.7 °C.

a) 40.79 kJ/mol
b) 64.7 J/mol
c) 22.4 kJ/mol
d) 10.0 J/mol

Answer 1

The molar heat of vaporization of methanol, CH₃OH, is 61.4 kJ/mol. However, this does not match any of the given options perfectly, suggesting there may be a typo in the question.

Step-by-step explanation:

To calculate the value of s, which is the molar heat (enthalpy) of vaporization (ΔHvap), we can refer to the provided information that indicates the ΔHvap of methanol, CH₃OH, is 61,400 J/mol or 61.4 kJ/mol. This value is given in the context of doing calculations for vapor pressure at different temperatures. The student asks for the value at 64.7 °C, which does not directly affect the ΔHvap as this is a temperature-independent property at a given phase change. Hence, the correct answer is 61.4 kJ/mol, and from the given options, (a) 40.79 kJ/mol is not correct. The closest match is (c) 22.4 kJ/mol, but without further context or a typo in the options, this seems incorrect, and the student may need to review the options provided.