Final answer:
The boiling point of a substance is the temperature at which it transitions from a liquid to a gas, which occurs when the vapor pressure of the liquid equals the external pressure. Boiling, or vaporization, is observable when bubbles form in the liquid as it reaches this critical temperature. The boiling point varies with pressure, with the 'normal boiling point' defined at a standard pressure of 1 atm.
Step-by-step explanation:
The process that relies on the boiling point of a substance is known as boiling or vaporization. The boiling point is the temperature at which a liquid becomes a gas. At this specific temperature, the vapor pressure of the liquid is equal to the external pressure exerted on the liquid. When a liquid reaches its boiling point, you might observe bubbles forming in the body of the liquid. These bubbles indicate that the molecules within have gained enough kinetic energy to overcome the atmospheric pressure and transition into the gas phase. This conversion from liquid to gas can be illustrated with water as an easy-to-understand example, as water boils at 100 °C at a pressure of 1 atmosphere (atm).
It's also important to understand that the boiling point and melting point of a substance can change based on the surrounding pressure. The normal boiling point is the boiling point of a substance at a pressure of 1 atm. As the pressure around a liquid changes, so too does its boiling point. Conversely, in a low-pressure environment, the boiling point is lower than it would be at standard atmospheric pressure.
Understanding the concept of boiling points is crucial when determining the state of a substance at a given temperature. The knowledge of a substance's boiling and melting points allows one to predict whether it will be in a solid, liquid, or gaseous state under specific conditions.