This document summarizes various experimental techniques for separating mixtures, including: 1. Solid-solid separation techniques like filtration, crystallization/evaporation, and dissolving/filtration. 2. Solid-liquid separation techniques like sublimation, dissolving/filtration, and simple distillation. 3. Liquid-liquid separation techniques like using a separating funnel and fractional distillation. It also briefly discusses paper chromatography for separating mixtures based on solubility in a solvent.

1. Experimental
Techniques
- methods of separation
and purification.
Done by : Ooi huiying

2. Solid-solid
 Filt r at ion
 Cr yst allisat ion & Evapor at ion t o dr yness
 Simple dist illat ion
Solid-liquid
 Sublimat ion
 Dissolving & f ilt r at ion
Liquid-liquid
 Separ at ing f unnel
 Fr act ional dist illat ion
Types of mixtures 

4. a) Filtration : separating an insoluble solid from liquid
 This method is used to separate an
insoluble solid from a liquid in a liquid-
solid mixture.
 The filter paper has tiny pores that allow
the liquid component to pass through it.
The insoluble solid particles that are too
large to pass through the filter paper are
left behind in the filter funnel. The
insoluble solid is called the residue and the
liquid that passes through is called the
filtrate.
Separating a solid from solid-
liquid mixture ( Filtration)

5. b) Crystallisation and evaporation to dryness
 During crystallisation, the concentrated sugar mixture is heated until saturated,
that is, at crystallisation point. The solution is left to cool so that the excess
sugar in the mixture will precipitate out as crystals. Some salts such as copper
sulfate, are also separated out from their solutions by crystallisation.
 Crystallisation is a separation method used to obtain pure sugar crystals from a
mixture. This method is suitable for salts that decompose if evaporated to
dryness on heating.
 Evaporation to dryness is used to separate a dissolved solid from a liquid. The
dissolved solid must be heat-stable.
 In this method, the mixture is heated. When the mixture has completely
evaporated, no water is left behind. The solid salt left behind as the residue.
Separating a solid from solid-
liquid mixture (crystallisation &
evaporation to dryness)

6. • c)Simple distillation : Separating a liquid from a solution
 Distillation is used to separate a pure
liquid from solid-liquid or liquid-
liquid mixture. The two main
processes involved in distillation are
boiling and condensation.
 The pure liquid collected from
distillation is called the distillate. The
solid that remains in the distillation
flask is called the residue.
 Uses: -To make perfumes
-Desalination plants
Separating a solid from solid-
liquid mixture ( simple Distillation)

7. 1) Sublimation: Separating a solid that sublimes on heating
 Sublimation is the process whereby the substances changes from the
solid state to gaseous state directly. Sublimation is used to separate a
solid that sublimes upon heating from another substance with a high
melting point.
 The mixture is placed in an evaporating dish. An inverted funnel is
placed over the mixture. On gentle heating, the salt sublimes and is
deposited on cold filter funnel.
 This method has limited uses because very few solids will sublime
on heating. Among those that will sublime are ammonium salts,
iodine, dry ice ( CO2).
Separating a solid from a
solid-solid mixture (Sublimation)

8. 2) Dissolving and filtration: When only one solid is soluble
 A mixture of two solids can be separated by carefully choosing a solvent in
which only one of the solids is soluble.
 The mixture of two solid can be used to mix with liquid. The soluble solid can be
used to dissolve in liquid, and a mixture is formed. Then filtration can occur.
The filter paper has tiny pores that allow the liquid component to pass through it.
The insoluble solid particles that are too large to pass through the filter paper are
left behind in the filter funnel. The insoluble solid is called the residue and the
liquid that passes through is called the filtrate.
 E.g. : To separate Copper (11) sulfate from a mixture of copper (11) oxide and
copper (11) suifate.
Separating a solid from a solid-
solid mixture (Dissolving and filtration)

9. • 1) Separating funnel : Separating immiscible liquid
 Liquids that do not dissolve in each other are described as immiscible. Oil and
water are immiscible in each other.
 Pour the mixture of oil and water into the separating funnel. Wait until two layers
are formed. Water is denser than oil. It will form the bottom layer. Open the tap.
Allow water (the bottom layer) to run into a beaker. Close the tap, before the top
layer runs out. Place another beaker below the funnel. Open the tap to allow the
oil to run out.
Separating liquid-liquid mixture
( Separating Funnel )

10. • b) Fractional distillation : Separating miscible liquids
 Miscible liquids are liquids that dissolve in each
other completely to form a solution. Fractional
distillation can be used to separate a liquid-liquid
mixture which is miscible and can only be used if
liquids have different boiling points.
 A tall fractionating column is used. It allows the
separation of different liquids more efficiently. It
contains many glass beads which provides a large
surface area for the vapour to condense on. The
substance with a lower boiling point is distilled first.
 Uses : Separation of liquid air
Separation of crude oil ( or petroleum)
Separation of ethanol from glucose solution
Separating liquid-liquid mixture
(Fractional distillation)

11.  It is used to separate a mixture which is based on the extent of solubility
in a given solvent.
 The result of the separated components on the chromatography paper is
called the chromatogram.
 The more soluble the component in the solvent, the further distance it
travels on the chromatography paper.
 Advantage: Gives quick & accurate analysis of sample, Requires only a
small amount of sample, Able to separate complex mixtures such as food
dyes or flavouring or the dyes in inks.
Rf=distance travelled by the substance
distance travelled by the solvent
Paper chromatography

12. The End