Freezing Point

The freezing point is the temperature at which a liquid turns into a solid when cooled. For pure water, the freezing point is 0 degrees Celsius (32 degrees Fahrenheit) at standard atmospheric pressure.

Factors Affecting Freezing Point

• Pressure: Changes in pressure can affect the freezing point of a substance. Generally, an increase in pressure will lower the freezing point, while a decrease in pressure will raise the freezing point.
• Impurities: Adding impurities, such as salt or sugar, to a liquid can lower its freezing point. This is why salt is often spread on icy roads to melt the ice.

Study Guide

1. What is the freezing point?
2. What is the freezing point of pure water?
3. How does pressure affect the freezing point?
4. What effect do impurities have on the freezing point of a liquid?
5. Give an example of how impurities are used to lower the freezing point of water.