Block 4 – Lesson 3

AIR IS A MIXTURE OF GASES

What is a mixture of substances?

Most substances in nature are mixtures of elements, for example air, water, soil and others. A mixture is a combination of two or more substances that keep their original properties.

What is a mixture of substances?

A fruit salad is a mixture because fruits can be separated from each other. Lemonade is a mixture, too.

What is a mixture of substances?

Homogeneous Mixtures

Homogeneous MixturesIt is not possible to distinguish the components at first glance because they are in equal proportions. For example: air, seawater, sugar water, milk and vinegar.

Heterogeneous Mixtures

Heterogeneous MixturesIt is possible to distinguish the components at first glance. For example: sand in water, a fruit salad and vinegar in oil.

Mixtures can be separated by the following means:

MECHANICAL AND PHYSICAL

MechanicalSEDIMENTATION:

SEDIMENTATION:

It separates solids from liquids through the action of gravity. It can also separate liquids that do not mix, for example: oil and water.

Mechanical

FILTRATION:

Mechanical

FILTRATION:

It separates solids from liquids by using filters.

Mechanical

SIFTING:

Mechanical

SIFTING:

It separates solids by using a sieve or strainer.

Mechanical

CENTRIFUGATION:

Mechanical

CENTRIFUGATION:

It separates the components of a homogeneous mixture by spinning.

Mechanical

MAGNETISM:

Mechanical

MAGNETISM:

It separates ferromagnetic materials by using magnets.

Mechanical

EVAPORATION:

Physical

EVAPORATION:

It separates solids from liquids by using the action of heat. The liquid evaporates and the solid stays in the container.

Physical

CRYSTALIZATION:

Physical

CRYSTALIZATION:

It separates solids from liquids by heat. It is an industrial method to purify substances.

Physical

So air is a mixture of many gases. Mainly Nitrogen and Oxygen, but it also contains Argon, CO2, Neon, Helium, Krypton, Hydrogen, Carbon Monoxide, Xenon, Ozone, Nitrogen Dioxide, Iodine, Ammonia… (mmm…doughnut!)