Certified Hyperbaric Technologist Practice Test

At what point do liquids transform into gas?

1. At sub-zero temperatures

2. When they reach their melting point

3. At their respective boiling points

4. When cooled significantly

The correct answer is: At their respective boiling points

The transition of liquids into gas occurs when they reach their respective boiling points. At this temperature, the vapor pressure of the liquid equals the atmospheric pressure, allowing molecules within the liquid to gain enough energy to overcome intermolecular forces and escape into the gas phase. This process is known as vaporization, and it can happen quickly depending on the specific properties of the liquid and the environmental conditions (such as pressure and temperature). In contrast, sub-zero temperatures typically cause liquids to solidify rather than turn into gas. The term "melting point" refers to the transition from solid to liquid, not liquid to gas. Lastly, cooling a liquid significantly would lead to condensation or freezing, rather than vaporization. The boiling point is the definitive stage where boiling occurs, leading to the conversion of the liquid into gas.