Separating mixtures

solid mixtures

Liquid mixtures

filtration

Magnetic attractions

Crystallisation

Filtration helps to separate an insoluble solid from a liquid

It helps to separate the dissolved solid inside a solution.

Examples:
-water and sand
-chalk powder and water

Separates the iron, steel, nickel and cobalt from other metals.

Residue=sand
Filtrate=water

Residue=chalk powder
Filtrate=water

An example would be sugar solution.

At the scrapyard, cranes with electromagnets separate magnetic metals from non-magnetic materials.

sublimation

Used to separate either solid or liquid mixture, that has a solid component which sublimes.

fractional distillation

Simple Distillation

Chromatography

Used to separate two or more soluble substances that dissolve in the same solvent like water or ethanol.

differences between evaporation and crystallisation

Example:
iodine solid and sand
ammonium chloride mixture


Heating followed by sublimation and deposition

Evaporation involves heating the solution to dryness.

On the other hand, crystallisation involves heating the solution until you obtain a saturated solution.

Processes

Used to determine the contents of pen ink to determine if the signature is forged or not.

Process 2: cooling

Process 1: heating

Used to test athletes’ urine samples to find out if they used performance enhancing drugs in their event, if positive, disqualified.

Examples:
liquid air
ethanol and water
crude oil

Examples: separating water from salt(sodium chloride) water.

The processes involved include heating up the solution, and condensing it through the condenser.

It is used to separate a pure solvent from a solution

Used to separate miscible (dissolved) liquid mixtures that have different boiling points

Same as simple distillation but.....

Procedure:

  1. Draw a line using pencil on the chromatogram paper.
  2. Put a dye on the line above the solvent
  3. Close the lid immediately

Longer because the liquid with lower boiling
point boils first and collected, followed by second liquid

Procedure:

  1. Heating solution
  2. Liquid with lower boiling point boils first and is later collected after condensation through condenser
  3. Liquid with higher boiling point will boil later and after condensation, is collected as a liquid in a separate flask

Apparatus (important): a condenser

The condenser is used to cool down the vapour into a pure liquid (distillate).

The Rf value is used to compare the solubility of different substances in the dye

Separating funnel

Another important apparatus is the thermometer.

It is the ratio between the distance traveled by the substance and the distance traveled by the solvent is a constant (c).


This ratio is called the Rf value.

The thermometer is placed usually at the mouth of the condenser. It measures the boiling point of the liquid.

A fractionating column is used in the process.
When both vapours rise up the column, the liquid with a higher boiling point is separated from the liquid with a lower boiling point.
The higher boiling point liquid condenses and falls back into the boiling flask.

If the chromatogram shows only one spot, the substance is pure, therefore, the purity of the substance is 100%

Used to separate immiscible (insoluble in each other) liquids

Water and oil

Procedure:
1.Two liquids allowed to separate from each other (oil floating above water)

  1. Liquid below is poured and collected, followed by second one