A. Among nonpolar liquids, those with higher molar masses tend to have normal boiling points that are (higher, lower, or about the same). b. Among compounds of approximately the same molar mass, those with greater polarities tend to have enthalpies of vaporization that are (higher, lower, or about the same).
c. Which is the only noble gas listed that is stable as a liquid at 0°C? Explain your answer using the concept of critical temperature.

Answers are below...and I have answered this question on the basis of above table.

Explanation :-

(a.) Among nonpolar liquids, those with higher molar masses tend to have normal boiling points that are (lower).

(b.) Among compounds of approximately the same molar mass, those with greater polarities tend to have enthalpies of vaporization that are (higher).

(c.) Xe (Xenon), a substance can exist only as a gas at temperatures above its critical temperature. Of the noble gases listed, only Xe has a critical temperature above O°c.

a compound is a molecule made of atoms from different elements.

a. by the combination of an unlimited number of elements

the answer is:  

line graphs show patterns in data with variables that change over time; whereas, circle graphs show data as parts out of a whole (such as out of 100%).