The heating curve of an ice-water mixture that is slowly heated to 125°C contains three sloped and two level portions. What do the two level portions in the graph represent?

Question

Responses
A heatingheating
B depositiondeposition
C sublimationsublimation
D phase changes

Answer 1

The two level portions in the heating curve represent phase changes. In a heating curve, the level portions indicate the temperature remaining constant as energy is added, which corresponds to a phase change: one level portion corresponds to the melting of ice into water (solid to liquid), and the other corresponds to the boiling of water into steam (liquid to gas). Therefore, the correct answer is:

D phase changes.