The terms compound and mixture both refer to combinations of substances, but they differ in their composition, properties, and how the components interact. Here’s a breakdown of the key differences:
1. Definition:
- Compound: A compound is a substance formed when two or more different elements chemically bond together in fixed proportions. The atoms in a compound are held together by chemical bonds (e.g., covalent, ionic).
- Mixture: A mixture is a combination of two or more substances (elements, compounds, or both) that are physically combined and not chemically bonded. The components can be present in any proportion.
2. Composition:
- Compound: The components of a compound are always present in a specific, fixed ratio (e.g., water (H₂O) always has two hydrogen atoms for every oxygen atom).
- Mixture: The components of a mixture can be in any proportion, and they retain their individual chemical properties (e.g., air is a mixture of nitrogen, oxygen, and other gases in varying proportions).
3. Bonding:
- Compound: The elements in a compound are chemically bonded, meaning the individual atoms are not easily separated without breaking chemical bonds.
- Mixture: In a mixture, the substances are physically combined, and no new bonds are formed. The components can be separated by physical methods such as filtration, distillation, or evaporation.
4. Properties:
- Compound: The properties of a compound are usually distinct from the properties of the individual elements that make it up (e.g., sodium chloride (NaCl) is a stable compound, while sodium and chlorine are dangerous on their own).
- Mixture: The properties of a mixture are the combined properties of the substances involved. The individual components retain their original properties (e.g., a mixture of sand and salt still has the properties of sand and salt).
5. Separation:
- Compound: To separate the components of a compound, a chemical reaction must occur (e.g., electrolysis of water to break it down into hydrogen and oxygen).
- Mixture: The components of a mixture can be separated by physical means (e.g., using a magnet to separate iron filings from sand).
6. Example:
- Compound: Water (H₂O), carbon dioxide (CO₂), sodium chloride (NaCl).
- Mixture: Air (a mixture of gases), salad, sand and salt mixture.
Summary:
A compound has a fixed, chemical composition and properties that differ from the individual elements it contains, while a mixture consists of substances that retain their original properties and can be separated physically.