Exam study: experiments

Question 1

What were the takeaway messages from the solubility lab?

Answer 1

Similar intermolecular forces increase solubility.

You can change the solubility of compounds by adding acid or base to protonate / deprotonate

Question 2

What were the takeaway messages from the chromatography lab?

Answer 2

When components of a mixture have different polarity, you can take advantage of it to distill compounds.

Question 3

What were the takeaway messages from the crystallization lab?

Answer 3

When components of a mixture have different solubilities depending on heat, you can dissolve them in heat, then crystallize out only one of them to purify.

Question 4

What were the takeaway messages from the distillation lab?

Answer 4

When components of a mixture have different boiling points, you can boil them and condense the vapor to purify.

Question 5

What is an azeotrope?

Answer 5

A mixture of two compounds whose vapor has the same composition as the liquid.

Represented as point on vapor-liquid comp diagram.

Question 6

What factors affect solvent choice in crystallization? (B.P vs solute MP? relationship between solvent/solute? solvent BP?)

Answer 6

Solvent B.P should be below melting point of solute

Solvent should not react with solute

Solvent should have low boiling point to evaporate better

Solvent should have large difference in solubility of solute with respect to temp