Physical separation techniques

Characteristics to separate mixture

Properties

Examples

Separating by particle size.

3 types

Sieving is used to separate a mixture of solids with different particle sizes (think sand in water)

Gravitational filtration is when you rely on the weight of the solid particles to filter the two materials

Vacuum filtration is faster than gravitational filtration, it is useful if the particles are light, and you want to dry out the mixture

• sand in water

Filtration

(Particle size)

Filtration can be used to separate an insoluble substance from a soluble substance.

• heterogeneous mixtures composed of solids and liquids,

How?

• a porous barrier to separate the solid from the liquid → (Liquid passes through leaving the solid in the filter paper.)

• heterogeneous mixtures

Separation by Density.

Sedimentation = (denser materials drop to the bottom)

decantation (After sedimentation → Ask teacher) is when you pour the liquid at the top away.

Separation funnels can be used when liquids don’t mix, the funnel has a tap at the bottom, and you can let the densest material out.

Centrifugation is when we spin a mixture in a centrifuge, → helps to settle finer particles that may not settle naturally

Separation by Boiling Point

Evaporation is when you boil off the liquid (solvent) and it leaves the dissolved material (solute) behind.

Distillation is evaporation but collect the gases. using a condenser to then converts the gas back into a liquid, and it is collected in a flask.

Fractional distillation used for mixtures many different substances in them, that all have slightly different boiling points.

• Homogeneous mixtures

Distillation & Evaporation

Used to separate homogeneous mixtures.

Based on differences in boiling points of substances involved.

Evaporation can be used to separate a solute from the solvent in a solution.

Crystallization.

(separation)

As one substance evaporates, the dissolved substance comes out of the ?solution and collects as crystals

• Produces highly pure solids

Separation technique that results in the formation of pure solid particles from a solution containing the dissolved substance

Rock candy

Separating by Electric Charge. ???

Electrostatic separation can be used to separate charged solid particles from a gas, many factories use this in their exhaust towers so that solid material in the fumes is removed.

Chromatography is a technique that relies on how “sticky” one material is to a static medium (e.g. resin or paper), this separates components of a mixture out.