7) In the heating curve shown below, heat is applied to a solid substance at a constant rate.
C
D
TEMPERATURE
TIME
What accounts for the fact that segment CD is longer than segment AB?
A)
Boiling occurs at a higher temperature than melting.
B)
The heat of vaporization is greater than the heat of fusion.
Average kinetic energy increases at a greater rate during boiling than during melting.
D)
Potential energy is being released during boiling.