Boiling Point

The boiling point of a substance is the temperature at which the vapor pressure of the liquid equals the external pressure surrounding the liquid. At this temperature, the liquid changes into a gas throughout the entire mass of the liquid.

Factors Affecting Boiling Point

Several factors can affect the boiling point of a substance:

1. Pressure: Increasing the pressure raises the boiling point, while decreasing the pressure lowers it. This is why cooking times can differ at high altitudes, where the atmospheric pressure is lower.
2. Intermolecular forces: Substances with stronger intermolecular forces require more energy to overcome these forces and reach the boiling point. Therefore, compounds with stronger intermolecular forces have higher boiling points.
3. Molecular weight: Generally, substances with higher molecular weights have higher boiling points because they have more electrons and a stronger attraction between molecules.

Study Guide

Here are some key points to remember about boiling points:

• Boiling point is the temperature at which the vapor pressure of a liquid equals the external pressure.
• Pressure, intermolecular forces, and molecular weight can affect the boiling point of a substance.
• Understanding boiling points is important in various fields, including cooking, chemistry, and material science.

Remember to consider these factors and concepts when studying the boiling point of a substance.