EXERCISE 3

Question 1

Relative ease of a substance’s change from liquid to gas.

Answer 1

Volatility

Question 2

Equilibrium vapor pressure is dependent on the _______________ and increases with ___________.

Answer 2

External pressure of the system. Temperature.

Question 3

Refers to rapid volatilization accompanied by turbulence and occurs when vapor pressure is equal to the externally applied pressure.

Answer 3

Boiling

Question 4

Boiling points may vary due to _______.

Answer 4

Fluctuations in atmospheric pressure.

Question 5

A basic separation technique that takes advantage of the volatility of desired substance to be separated from the rest of the mixture.

Answer 5

Distillation

Question 6

Sample used in simple distillation.

Answer 6

Homogeneous mixture that can have a nonvolatile solute and volatile solvent or one liquid being more volatile than the other.

Question 7

Sample used in steam distillation.

Answer 7

Heterogeneous mixture of water and a slightly volatile liquid with higher boiling point than water.

Question 8

Law used in simple distillation stating that the vapor pressure of a compound is lowered when it becomes part of a solution.

Answer 8

Raoult’s Law

Question 9

Equation of Raoult’s Law.

Answer 9

Pa = vapor pressure of compound in pure form x its mole fraction in the mixture

Question 10

Law used in steam distillation stating how water codistills with the desired compound.

Answer 10

Dalton’s Law of Partial Pressure

Question 11

Contents of distillate in simple distillation.

Answer 11

Desired Substance

Question 12

Contents of distillate in steam distillation.

Answer 12

Water and oily droplets of desired substance.

Question 13

Mixture starts boiling in simple distillation at what temperature?

Answer 13

Boiling point of desired substance.

Question 14

Mixture starts boiling in steam distillation at what temperature?

Answer 14

Lower than the boiling point of both components.

Question 15

Conditions for using simple distillation.

Answer 15

Substances must have wide differences in boiling point.

Question 16

Conditions for using steam distillation.

Answer 16

1. Substance are volatile and water immiscible.
2. For purification of substances that are sensitive to heat and undergoes thermal degradation.
3. Mixtures containing large amounts of nonvolatile material.

Question 17

Required characteristics exhibited by sample used in steam distillation.

Answer 17

1. Liquid at room temp.
2. Slightly volatile.
3. Water immiscible.