Diffusion and osmosis

The osmometer uses supercooling to measure the depression of the freezing point. Supercooling is the process of cooling a liquid without causing a change in state. It involves rapidly cooling a sample to a temperature below its expected freezing point. The substance does not form a solid structure because freezing requires a seed crystal or nucleus around which a crystal structure can form. Once the desired temperature is reached, a physical shock called the ‘freeze pulse’ is introduced, which helps initiate rapid freezing by aligning some molecules to create a crystal seed. The crystallisation process releases the heat of fusion, which causes the temperature of the sample to rise. The temperature increases until equilibrium between the solid and liquid phases is established. At this point, the temperature represents the freezing point.

Only gold members can continue reading. Log In or Register to continue