Question

Which of the following is a substance according to scientific meaning: air, water, smoke, fog

Answer 1

Substance - A substance is a pure single form of matter. It consists of a single type of particle and is the same in chemical nature.

Mixture: A substance that consists of two or more pure substances (elements or compounds) mixed together in any proportion so that components do not lose their identity.

1. Air is a mixture of several gases and particulate matter.
2. Water is a pure substance because it is a compound made of hydrogen and oxygen.
3. Smoke is a mixture of tiny solid and liquid particles as well as gases that escape from burning objects such as stoves, candles, and internal engine parts.
4. Fog is made up of microscopic liquid water droplets floating in the air or near the earth’s surface, as well as ice crystals.

Therefore, water is a substance while smoke, air, and fog are a mixture.