Classification of Matter:
1. Elements.
2. Compounds.
3. Mixtures.
Compounds:
A compound is a substance formed when two or more elements are chemically combined together and can be separated only by chemical means into the substances it is composed of. Examples of chemical compounds are water (H2O), sodium chloride or salt (NaCl), ethanol (C2H5OH), etc.
Properties of a Compound
1. The components of compounds are chemically combined together and they can only be separated by chemical means.
2. Compounds have a fixed boiling point, freezing point and melting pointThe temperature at which a solid changes its state to liquid at atmospheric pressure is called the melting point of that liquid. The melting point is usually defined as the point... More.
3. The properties of compounds are different from the properties of their components.
Examples of some commonly used compounds and their molecular formula:
| Compound Name | Compound Formula |
| Alcohol | C2H6O |
| Acetic Acid | C2H4O2 |
| Sulphuric Acid | H2SO4 |
| Ammonia | NH3 |
| Methane | CH4 |
| Nitrous oxide | N2O |
| Salt | NaCl |
Elements:
An element is a substance that cannot be broken down into simpler components. Examples of elements are oxygen, carbon, hydrogen, magnesium, nitrogen, chlorine, etc.
Examples of some commonly used elements along with their chemical symbols:
| Name of the element | Chemical symbol |
| Hydrogen | (H) |
| Boron | (B) |
| Carbon | (C) |
| Silicon | (Si) |
| Sodium | (Na) |
| Lead | (Pb) |
| Platinum | (Pt) |
Mixtures:
A Mixture is the physical combination of two or more substances, which can also be separated by physical means. Examples are air, crude oil, and seawater.
A mixture of salt and sand can easily be made by mixing the substances together. It can be separated into the constituent component because of no chemical change is involved in its formation. Some mixtures are not made but occur naturally. Some examples are air, crude oil, etc.
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