The temperature at which a substance changes from a liquid to a gas is called what?

The temperature at which a substance changes from a liquid to a gas is called what?

• A. Boiling point
• B. Freezing point
• C. Melting point
• D. Absolute zero

Answer: (A)

The main concept is the temperature at which a liquid becomes a gas, which is its boiling point. At this temperature, the liquid’s vapor pressure matches the surrounding pressure, allowing bubbles of vapor to form inside the liquid and rise to the surface as it changes to gas. This is what defines a boiling point and distinguishes it from evaporation, which can happen below that temperature at the surface. For water at standard pressure, the boiling point is 100°C. The other terms refer to different phase changes: the freezing point is when a liquid becomes a solid, the melting point is when a solid becomes a liquid, and absolute zero is the lowest possible temperature.

The main concept is the temperature at which a liquid becomes a gas, which is its boiling point. At this temperature, the liquid’s vapor pressure matches the surrounding pressure, allowing bubbles of vapor to form inside the liquid and rise to the surface as it changes to gas. This is what defines a boiling point and distinguishes it from evaporation, which can happen below that temperature at the surface. For water at standard pressure, the boiling point is 100°C. The other terms refer to different phase changes: the freezing point is when a liquid becomes a solid, the melting point is when a solid becomes a liquid, and absolute zero is the lowest possible temperature.