cbse class 9th subject science ch 2 topic 2.3 physical and chemical change and it's types of pure substance full notes
Answers
Explanation:
Pure Substance: The substances that are free from any kind of mixture and contain only one kind of particle are pure substances. Examples of pure substances include iron, aluminum, silver, and gold.
Mixtures: Substances that have two or more different particles are mixtures. Examples of mixture include the salt solution which is a ‘mixture’ of two components, salt, and water.
Types of Pure Substances
Based on their chemical composition, pure substances are classified into two categories:
Elements
Compounds
Element
A pure substance that has only one kind of atom and cannot be broken into two or more simpler substances by physical or chemical means is an element. Therefore, when you break down gold, you still get gold. It is an element.
Compound
A pure substance, basically composed of two or more elements and chemically combined in a fixed proportion is called a compound. Therefore, water is a compound. It has two elements, hydrogen and oxygen, combined in a fixed ratio.