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Mixtures

What is a mixture?

A mixture is an impure substance that can be separated into pure substance by physical means. eg. dirty water can be purified by filtration.

There are many different methods of separating mixtures. Each method relies on differences in the physical properties of the components of the mixture.

Methods of Physical Separation

Method of separation Used to separate Basis - differences in Example
Filtration An insoluble solid from a liquid Solubility Muddy water
Decanting An insoluble solid from a liquid Solubility and density Water and sand
Centrifuging An insoluble solid from a liquid Solubility and density Blood cells from plasma
Evaporating A soluble solid from a liquid Boiling point Salt from sea water
Distillation A liquid from a soluble solid Boiling point Water from sea water
Fractional distillation

Miscible liquids

(liquids that can be mixed together as one)

Boiling point Alcohol from water
Separating funnel Immiscible liquids (liquids that do not mix) Density and miscibility Oil and water
Paper chromatography Soluble substances Retention rates on paper Food coloring
Crystallization Soluble substances Solublility Different salts