Heat Is Added to a Pure Substance in a Closed

question 82

Multiple Choice

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

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Definitions:

Rush

A spasm of warmth and ecstasy that occurs when certain drugs, such as heroin, are ingested.

Heroin

An illegal opioid drug derived from morphine, highly addictive and known for its powerful euphoric effects.

Injection

The act of administering a liquid, especially a drug, into the body using a needle and syringe.

Barbiturates

A class of drugs used as sedatives and hypnotics, historically prescribed for anxiety, insomnia, and seizure disorders, now less common due to the risk of dependence.