Boiling Point

The boiling point is the temperature at which boiling occurs for a specific liquid. For example, for water, the boiling point is 100 degrees Celsius at a pressure of 1 atm. The boiling point of a liquid depends on temperature, atmospheric pressure, and the vapor pressure of the liquid. When the atmospheric pressure is equal to the vapor pressure of the liquid, boiling will begin.

Video: Boiling Point

When boiling occurs, the more energetic molecules change to a gas, spread out, and form bubbles. These rise to the surface and enter the atmosphere. It requires energy to change from a liquid to a gas. In addition, gas molecules leaving the liquid take away heat energy. Therefore the temperature of the liquid remains constant during boiling. For example, at sea level water will remain at 100 degrees Celsius (at a pressure of 1 atm or 101.3 kPa) while boiling.