jäätymispisteenä

Jäätymispisteenä refers to the temperature at which a liquid transitions into a solid state. This process is known as freezing. For pure substances, the freezing point is a specific and constant temperature under a given pressure. For example, pure water freezes at 0 degrees Celsius (32 degrees Fahrenheit) at standard atmospheric pressure.

The freezing point is influenced by several factors. The most significant is pressure. For most substances, an increase in pressure raises the freezing point. However, water is an exception, where increasing pressure lowers its freezing point. This anomaly is due to the unique crystalline structure of ice.

Impurities also affect the freezing point. When a solute is dissolved in a solvent, the freezing point of the solvent is typically lowered. This phenomenon is called freezing point depression and is a colligative property, meaning it depends on the concentration of solute particles, not their identity. Antifreeze, for instance, is added to car radiators to lower the freezing point of water, preventing the coolant from freezing in cold weather.

The freezing point is an important thermodynamic property and is utilized in various applications, from determining the purity of substances to understanding natural phenomena like the formation of ice on lakes and rivers. It is the reverse of the melting point, which is the temperature at which a solid transitions back into a liquid. For pure substances, the freezing point and melting point are the same temperature under identical pressure conditions.