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Science

Air and molecular compounds

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The Earth is surrounded by an atmosphere that is a mixture of gases. Some of these gases are molecular elements, and some are molecular compounds.

Composition of dry air

air is made up of nitrogen (78%), oxygen (21%) and other gases (1%)

The composition of air

The air contains a number of gases. The amount of water vapour in the air varies from place to place, and day to day. For this reason, the proportions of the gases in the air are usually given for dry air.

Some of the gases in the air are elements: nitrogen (N2), oxygen (O2) and argon (Ar). But carbon dioxide (CO2) is a compound (as is and water vapour, H2O).

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Back to Chemicals of the natural environment index

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