The boiling point of any pure substance is the temperature at which, under common atmospheric pressure, that substance changes its state from liquid to gas. If the substance is a gas at 25 degrees Celsius, this temperature is sometimes called the ''condensation point''. | The boiling point of any pure substance is the temperature at which, under common atmospheric pressure, that substance changes its state from liquid to gas. If the substance is a gas at 25 degrees Celsius, this temperature is sometimes called the ''condensation point''. |