Phase Changes: Heat Is Added to a Pure Substance in a Closed

question 109

Multiple Choice

Phase changes: Heat is added to a pure substance in a closed container at a constant rate. The figure shows a graph of the temperature of the substance as a function of time. If L_f = latent heat of fusion and L_v = latent heat of vaporization, what is the value of the ratio L_v / L_f for this substance?

• A) 5.0
• B) 4.5
• C) 7.2
• D) 3.5
• E) 1.5

---

Definitions:

Viagra

A pharmaceutical drug used primarily to treat erectile dysfunction by increasing blood flow to the penis.

Premature Ejaculation

A sexual disorder characterized by ejaculation that occurs sooner than desired, either before or shortly after sexual penetration.

Behaviorally Oriented Therapy

A type of psychotherapy that focuses on changing undesirable behaviors through conditioning techniques.

Ejaculate

The release of semen from the body during orgasm in males.