1. A phenomenon called supercooling is frequently encountered in this experiment
ID: 999689 • Letter: 1
Question
1. A phenomenon called supercooling is frequently encountered in this experiment. supercooling, a solution momentarily drops below its freezing point, and then warms up again, before solidification begins. What event is likely to give rise to supercooling?
2. The molal freezing point constant, Kf , is a property of the solvent, not the solute. What does this say about the fact that freezing point depends on the amount of solute, rather than on the solute’s nature?
3. A phenomenon that happens sometimes during freezing point depression experiments is that the solute is affected in some manner by the solvent. One common occurrence is for a solute to dimerize, that is, two solute molecules combine to produce a single double molecule (a dimer). What effect would there be on a molar mass determination if the solute were to dimerize?
Explanation / Answer
1.- Supercooling may be given to extremely rapidly cooling the liquid, avoiding its nucleation, until achieving its homogeneous nucleation.
2.- Obviously solute molecules interact or interfere with the normal movement of solvent molecules seriously affecting this propertie. Possibly the presence of solute molecules hinders the crystallization of the liquid.
3.- If the solute dimerized, the solution would behave as if it had half as many particles dissolved in it. You would end up calculating a molar mass based on fewer mols. Some mass divided by fewer moles gives you a larger calculated mass per mole.
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