Question

The purging of impurities from a compound by crystallization:

occurs when the compound is put under great pressure

occurs when the compound is vaporized

occurs after the liquid melt cools back to a solid

occurs after condensation from the vapor phase

Answer 1

Answer;

occurs after the liquid melt cools back to a solid

The purging of impurities from a compound by crystallization occurs after the liquid melt cools back to a solid.

Explanation;

• Purging of impurities from a compound by crystallization is done through a method known as melt crystallization. Melt crystallization is a type of cooling crystallization process which is operated close to the melting point of the pure compound.
• The sample for melt crystallization id normally an impure compound. When the impure sample is cooled below the equilibrium temperature the result is formation of a solid phase which is more pure that the initial compound, while the impurities remain in the impure sample.

Answer 2

C.

This is also the only change by which crystals may be produced.