Question

A substance has a boiling point of 78 °C. Which of the following is true about the substance? (5 points) a It will also change from a gas to a solid at 78 °C while the gas loses energy. b It will also change from a gas to a solid at 78 °C while the gas gains energy. c It will also change from a gas to a liquid at 78 °C while the gas loses energy. d It will also change from a gas to a liquid at 78 °C while the gas gains energy.

Answer 1

Answer: If a substance has a boiling point of $78^{o}C$ then it is true that it will also change from a gas to a liquid at 78 °C while the gas loses energy.

Explanation:

The temperature at which vapor pressure of a liquid substance becomes equal to the atmospheric pressure is called boiling point of substance.

At the boiling point, liquid phase and vapor phase remains in equilibrium.

This means that as liquid phase changes into vapor phase and also vapor phase changes into liquid phase at the boiling point.

Thus, we can conclude that if a substance has a boiling point of $78^{o}C$ then it is true that it will also change from a gas to a liquid at 78 °C while the gas loses energy.