Calculate the standard entropy of vaporization of ethanol at its boiling point, 352 k. the standard molar enthalpy of vaporization of ethanol at its boiling point is 40.5 kj/mol.
a. +40.5 j/mol k
b. +115 j/mol k
c. -40.5 j/mol k
d. -115 j/mol k

Answer : The correct option is, (b) +115 J/mol.K

Explanation :

Formula used :

where,

= change in entropy

= change in enthalpy of vaporization = 40.5 kJ/mol

= boiling point temperature = 352 K

Now put all the given values in the above formula, we get:

Therefore, the standard entropy of vaporization of ethanol at its boiling point is +115 J/mol.K

the formula mass of a molecule or a compound is the sum of the atomic weights of the atoms in its empirical formula

(that's what i know about formula mass)