What change occurs to molecule of a liquid as the liquid becomes as
The average mass of molecules decreases
The average mass of molecules increases
The spacing Bersen molecules decreases
The spacing between molecules increases

what is the volume occupied by 40 grams of argon gas (ar) at standard conditions? what volume, in liters, is occupied by 1.5 x 1023 

i believe you are right for all except the 3rd ( look at sqdancefan his answer is much better)

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)