Pure Substances/Physical Mix

All matter can be classified as either a pure substance or a physical mixture.

PURE SUBSTANCE

A pure substance is a chemical combination of matter in a definite (fixed) proportion.

Pure substance have unique properties (because its composition is fixed and constant)

Most substances do not exist in a pure state

Examples of Pure Substance: Water and Salt

Water: 2 hydrogen atoms per oxygen atom (H20)

Salt: 1 sodium atom per chlorine atom (NaCI)

Its recipe will always be the same.

PHYSICAL MIXTURES

A physical mixture is a physical combination of matter in any proportion but is not chemically bonded.

❗❗Solutions, suspensions and emulsions are all also physical mixtures.

Examples of Physical Mixtures:

> Saltwater: When you put salt in water. You get a mixture but also the sand is still sand and the water is still water. The salt and water molecules do not chemically bond, they just mix water. The properties are the properties contained in salt water: salt water is salty and wet.

> Sand and Water

> Fruit Salad