The standard entropy of liquid methanol at 298K is 126.8 J/K-mol and its heat capacity is 81.6 J/K-mol. Methanol boils at 337K with an enthalpy of vaporization of 35.270 kJ/mol at that temperature. The heat capacity of the vapor is 43.9 J/K-mol.__Calculate the entropy of one mole of methanol vapor at 800 K.

Explanation:

First, we will calculate the entropies as follow.

  J/K mol

As,   = 298 K,         = 373.8 K

Putting the given values into the above formula we get,

      J/K mol

                 =

                 = 18.5 J/K mol

Now,

                  =

                  = 94.2 J/mol K

Also,

                =

                = 33.4 J/K mol

Now, we will calculate the entropy of one mole of methanol vapor at 800 K as follows.

                 = (126.8 + 18.5 + 94.2 + 33.4) J/K mol

                 = 272.9 J/K mol

Thus, we can conclude that the entropy of one mole of methanol vapor at 800 K is 272.9 J/K mol.