Question

Use the heating–cooling curve below to answer the following questions.

a. What is the freezing point of the liquid?

b. What is the boiling point of the liquid?

c. Which is greater, the heat of fusion or the heat of vaporization? Explain each term, and explain how the heating–cooling curve above helps you to answer the question.

Short answer

a. According to the graph, the freezing point of the substance begins at 20⁰C.

b. According to the graph, the boiling point of the substance will begin at 120⁰C.

c. The heat of vaporization is greater than the heat of fusion (as the slope parallel to or a plane parallel to is shorter in length at the heat of fusion compared to the heat of vaporization).

Step-by-step solution

Heat of fusion

The heat of fusion is the amount of heat energy required to change the state of matter of a substance from solid to liquid.

Heat of vaporization

The heat of vaporization is the amount of heat energy required to change the state of matter of a substance from liquid to gas or vapor.

The heat of vaporization mainly depends upon the intermolecular forcesbetween the molecules.

Explanation

a. According to the graph, the freezing point of the substance begins at 20⁰C.

b. According to the graph, the boiling point of the substance will begin at 120⁰C.

c. The heat of vaporization is greater than the heat of fusion (as the slope parallel to or a plane parallel to is shorter in length at the heat of fusion compared to the heat of vaporization).