Here's why:
* Pure Substance: This means the substance is made up of only one type of particle. It's not a mixture of different things.
* Chemical Reaction: This involves the breaking and forming of chemical bonds between atoms.
* Compound: A compound is formed when two or more different elements chemically combine in a fixed ratio. This means the elements are held together by chemical bonds.
Example:
Water (H₂O) is a pure substance (only water molecules) and a compound (formed from hydrogen and oxygen). You can break it down into its constituent elements through electrolysis (a chemical reaction).
Important Note: Elements themselves are pure substances but cannot be broken down into simpler substances by chemical reactions. They are the building blocks of all matter.
