Question

4. Air is not a pure substance. Justify.

Answer 1

Answer:

air is a mixture of different elements and compounds.

elements include

nitrogen (~78%)

oxygen (~21%)

argon (~1%)

compounds include

carbon dioxide (~0.04%)

compounds are made up of different atoms chemically combined together.

elements are entirely made up of atoms of the same type.

there are many different gases in air, and these gases are not chemically combined. instead, they are a mixture of different gases.

Hope this helps!!!

Answer 2

Air isn't considered a pure substance because there is no one single chemical element of compound that forms air. Air is a mixture of various purechemical substances, most of which exist in the gaseous state.

Air is a mixture, mostly of nitrogen (78%) and oxygen (20%)

There are other gasses as well, argon slightly less than 1% and of course carbondioxide which is not as abundant as one might think (.04%) considering

it's breathed out by every animal on earth
volcanoes spew a considerable amount as well (150-270 million metric tons/yr)
and human activity produces even spectacularly more (36 billion metric tons/yr)
Yes, you read that right, billions versus millions. Humans produce about 130 times as much CO2 as does nature. Even so, as a percentage it's a very small (but vitally important ! ) component of our atmosphere.

The remaining less than 1% is made up of neon, helium, methane, etc.