Separation Techniques

Question 1

What are Separation Techniques?

Answer 1

• separation techniques are the physical means used to separate mixtures based on the properties of the substances in the mixture, and hence, the type of mixture

Question 2

What is Simple Filtration?

Answer 2

• used to separate solids from suspensions in a liquid solution
• bigger particles will not pass through the filter (residue)
• smaller particles will pass through the filter (filtrate)

The principle of separation is the difference in particle size

Question 3

What is Simple Distillation?

Answer 3

• a method of separating the solvent from the solution
• effective when the difference in boiling points is greater than 70°C

Question 4

What is Fractional Distillation?

Answer 4

• a method of separating a mixture into different parts based on their different boiling points
• effective when the difference in boiling points is less than 25°C

The principle of separation for both simple and fractional distillation is difference in boiling points

Question 5

Why is Fractional Distillation used?

Answer 5

• if simple distillation was used when the difference in boiling points is small, then the substance with the lower boiling point will evaporate first, but because of the close boiling points, the other substance will be evaporated to and the mixture will not be separated properly so fractional distillation uses a fractional column so that distillation occurs in series.

Question 6

What is Paper Chromatography?

Answer 6

• an analytical method used to separate coloured chemicals or substances

The principle of separation is the attraction of components to the stationary and the mobile phase

Question 7

How does Chromatography work?

Answer 7

• the stationary phase is the chromatography paper and the mobile phase is the liquid moving over the paper. The component more attracted to the mobile phase will move along with the liquid while the component more attracted to the stationary phase will stay at the bottom.

Question 8

What is Magnetism?

Answer 8

• the separation of magnetic substances from non-magnetic substances in a mixture

The principle of separation is the difference in magnetic properties of the substances

Question 9

What is Decantation?

Answer 9

• involves the separation of solids from a suspension by simple pouring off the liquid once the solids have settled

The principle of separation is the difference in particle size

Question 10

What is Centrifugation?

Answer 10

• used to separate colloidal mixtures
• involves rapidly spinning the mixtures to separate components based on their density

The principle of separation is difference in density

Question 11

What are Separating Funnels?

Answer 11

• a piece of laboratory equipment used to separate two immiscible liquids
• the liquids will have different densities

The principle of separation is difference in density

Question 12

How does the Separating Funnel work?

Answer 12

• the separating funnel has a stopcock, which when opened, the more dense liquid at the bottom will flow out. The stopcock is then closed and the less dense liquid is left behind