A Positive Slope for a Region of a Heating Curve

Multiple Choice

A positive slope for a region of a heating curve indicates that ____ in that region.

A) no energy is being absorbed by the system
B) energy is being given off by the system, but it cannot be measured
C) energy is being absorbed by the system and is being used for a phase change
D) additional data is needed to explain this observation
E) energy is being absorbed by the system and is being used to increase the temperature