Separation Techniques

Question 1

What is a separation technique?

Answer 1

A separation technique is a method used to separate mixtures based on their physical or chemical properties.

Question 2

What properties can be used to apply separation techniques?

Answer 2

State of matter, solubility in water, rate of migration over an adsorbent, ability to be attracted by a magnet, boiling point, size of the particle, density, and reactivity.

Question 3

What is sieving?

Answer 3

Sieving is a separation method used to separate particles of different sizes using a sieve.

Question 4

Give an example of a mixture that can be separated by sieving.

Answer 4

A mixture of stones and sand.

Question 5

What is filtration?

Answer 5

Filtration is a method used to separate a solid-liquid mixture using a filter paper, where the liquid that passes through is called the filtrate, and the solid that remains is called the residue.

Question 6

In filtration, should the solid be soluble or insoluble in the liquid?

Answer 6

The solid must be insoluble, otherwise, it would dissolve in the liquid, rendering filtration ineffective.

Question 7

What is decantation?

Answer 7

Decantation is a technique used to separate immiscible liquid-liquid mixtures or suspensions of solids in liquids by allowing the layers to form and then pouring off one layer.

Question 8

How is decantation different from sedimentation?

Answer 8

Sedimentation allows heavier particles to settle, while decantation involves removing the liquid layer without disturbing the sediment.

Question 9

What is centrifugation?

Answer 9

Centrifugation is a technique used to separate suspensions of solids in liquids by applying centrifugal force in a centrifuge.

Question 10

Where is centrifugation commonly used?

Answer 10

In medicine to separate blood components and in washing machines to separate dirt from clothes.

Question 11

What is magnetic separation?

Answer 11

Magnetic separation is a technique used to separate magnetic substances from non-magnetic ones.

Question 12

Give an example of a mixture that can be separated by magnetic separation.

Answer 12

A mixture of iron filings and sulfur powder.

Question 13

What is sublimation?

Answer 13

Sublimation is a technique used to separate volatile solids (sublimes) from non-volatile solids, where the solid vaporizes directly without passing through a liquid phase.

Question 14

List examples of substances that sublime.

Answer 14

Iodine, camphor, ammonium chloride, dry ice, and naphthalene.

Question 15

What is the method used to separate a mixture of ammonium chloride and iodine?

Answer 15

Sublimation, because ammonium chloride sublimes at a lower temperature compared to iodine.

Question 16

What is evaporation?

Answer 16

Evaporation is a technique used to separate soluble solid particles from liquids by heating the mixture until the liquid evaporates, leaving the solid behind as residue.

Question 17

What are the drawbacks of evaporation?

Answer 17

Evaporation doesn’t remove impurities, and some substances may decompose upon heating.

Question 18

What is crystallization?

Answer 18

Crystallization is a technique used to recover dissolved solutes from a supersaturated solution in the form of crystals.

Question 19

What is the principle behind crystallization?

Answer 19

Crystallization is based on the principle that solubility increases with temperature, and cooling a supersaturated solution allows crystals to form.

Question 20

What is distillation?

Answer 20

Distillation is a separation technique used for liquid-liquid mixtures based on differences in boiling points or volatilities.

Question 21

What is the difference between simple and fractional distillation?

Answer 21

Simple distillation is used for mixtures with a wide difference in boiling points, while fractional distillation is used for mixtures with a small difference in boiling points.

Question 22

What is an azeotropic mixture?

Answer 22

An azeotropic mixture is a constant boiling mixture that cannot be completely separated by distillation or fractional distillation.

Question 23

What method is used to separate the color extracts of a flower?

Answer 23

Chromatography.

Question 24

What method is used to separate a powdered mixture of alum and chalk?

Answer 24

Filtration, followed by evaporation to dry the alum.

Question 25

What method is used in the separation of sodium chloride and naphthalene?

Answer 25

Sublimation to remove naphthalene and then filtration to separate the remaining sodium chloride.

Question 26

What separation technique does a washing machine use?

Answer 26

Centrifugation.