Which of the following processes requires heat to change a substance from liquid to gas?

Which of the following processes requires heat to change a substance from liquid to gas?

• A. Condensation
• B. Vaporization
• C. Fusion
• D. Solidification

Answer: (B)

Vaporization is the process that requires heat to change a substance from a liquid to a gas. This occurs when the molecules within the liquid gain sufficient energy to overcome the intermolecular forces that hold them together, allowing them to move freely as gas molecules. Heat is necessary to provide this energy, which is why vaporization often takes place during boiling or evaporation, both of which involve the absorption of heat. In contrast, condensation refers to the process where gas turns into a liquid, which releases heat. Fusion, also known as melting, is the transition from solid to liquid and similarly requires heat, while solidification refers to the process of a liquid turning into a solid, releasing heat in the process. Therefore, vaporization is distinctly characterized by the input of heat to achieve the change from liquid to gas.

Vaporization is the process that requires heat to change a substance from a liquid to a gas. This occurs when the molecules within the liquid gain sufficient energy to overcome the intermolecular forces that hold them together, allowing them to move freely as gas molecules. Heat is necessary to provide this energy, which is why vaporization often takes place during boiling or evaporation, both of which involve the absorption of heat.

In contrast, condensation refers to the process where gas turns into a liquid, which releases heat. Fusion, also known as melting, is the transition from solid to liquid and similarly requires heat, while solidification refers to the process of a liquid turning into a solid, releasing heat in the process. Therefore, vaporization is distinctly characterized by the input of heat to achieve the change from liquid to gas.