The following are the answers to the questions presented:
a. Mols = [tex]\frac{20g}{85g/m} [/tex]
b. 88g – 20g = 68g
c. Evaporation of water / Boiling of water
I am hoping that these answers have satisfied your queries and it will be able to help you in your endeavors, and if you would like, feel free to ask another question.