1. A pure substance does not have to be of a single element or compound. A substance that has a fixed chemical composition throughout is called a pure substance such as water, air, and nitrogen. Air is also often considered as a pure substance.
2. Mixtures are the substances composed of two or more forms of matter. You can separate them by physical methods. Mixtures can be classified on the basis of particle size into three different types: solutions, suspensions, and colloids.
3. An element is a chemical element refers to the pure substance of one type of atom. An element cannot be broken down into any other substance. Common examples include carbon, sulfur, oxygen, iron, copper, aluminium.
4. A compound is a chemical substance that combines two or more elements. It is made up or consisting of two or more existing parts or elements. Water, carbon dioxide and table salt are some examples of compounds.
5. A homogeneous mixture is a mixture in which the composition is uniform throughout the mixture. Homogeneous mixtures can be solid, liquid, or gas. Examples of Homogeneous Mixtures include Water, Air, Steel, Detergent, Saltwater mixture, etc.
6. A heterogeneous mixture is a mixture in which the composition is not uniform throughout the mixture. By definition, a pure substance or a homogeneous mixture consists of a single phase. A heterogeneous mixture consists of two or more phases.
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