1) Separation of mixtures of solids by physical methods can be based on difference in the following except
A. melting point B. solubility C. particle size
D. molar mass E. magnetic property
Solution
Molar mass is not a physical properties of a solid. (D)

2) Which of the substances lettered P to V in the equation
below would be left on the filter paper if the reaction
mixture were filtered
P(aq) + Q(aq)  V(s) + R(aq) + T(g)

A. P B. Q C. V D. T E. R
Solution
V, this is because only the solid substance remains in the
filter paper after filtration. (C)

3) Which of the following methods can be used to separate a mixture of two miscible liquids with different boiling points?
A. decantation B. distillation
C. evaporation D. filtration

Solution
Distillation, this is because of the property such as boiling
point, when the boiling points are far we use distillation
when relatively close we use fractional distillation. (B)

4) The most suitable method to use when separating an
insoluble solid from a liquid is
A. evaporation B. filtration C. sublimation
D. distillation

Solution
Filtration technique is useful for separating an insoluble
solid from a liquid. This is because most of the solids are
recovered. Correct option is B.

5) Liquefied air is mainly a mixture of nitrogen and oxygen which can be separated into its components by fractional distillation. (boiling point of oxygen is –196°C, boiling point of oxygen is –174°C).
(a) Name the fraction which distills over first. Give the
reason for your answer.
(b) Give another industrial application of fractional
distillation as a separation technique.

Solution
(a) Nitrogen distills over first. This is because it is more
volatile and boils at a much lower boiling point than
oxygen (–183°C).
(b) Fractional distillation of crude oil. Crude oil contains
many important fractions such as natural gases, petrol,
kerosene, gas oil, heavy oil and bitumen.