The accompanying graph shows the heating curves for one mole each of substances A and B, at one atmosphere pressure.

(a) Give the melting and boiling points for each substance.

(b) Which substance has the greater enthalpy of vaporization?

(c) Which substance has a greater molar heat capacity in the liquid phase?

(d) Which substance has the stronger intermolecular forces of attraction?

Strategy

Refer to the heating curve for approximate melting and boiling points. The enthalpy of vaporization is related to the length of the horizontal vaporization line, whereas the slope of the temperature-change segments is related to the heat capacity.

Transcribed Image Text:

Temperature (C) 140 120 100 80 60 40 20 0 -20 -40 -60 -80 -100 B A Heat added