List four characteristics of a mixture.

A mixture is a substance formed by the physical combination of two or more substances that are not chemically bonded.

1. No New Substance is Formed

The formation of a mixture is a physical change, not a chemical reaction. The individual components are simply intermingled, and no new chemical substance is created. For example, when you mix sand and sugar, you just have a container of sand and sugar together.

2. Components Can Be in Any Proportion

The constituents of a mixture can be mixed in any ratio or proportion by mass. You can add a little salt to water or a lot of salt to water; in both cases, you have created a saltwater mixture. This is unlike a compound, like water (H₂O), which always has a fixed ratio of hydrogen to oxygen.

3. Components Retain Their Individual Properties

Each substance in a mixture keeps its own original properties. In a mixture of salt and water, the water is still a liquid that freezes at 0°C, and the salt still has its characteristic salty taste. The properties of the components do not change.

4. Components Can Be Separated by Physical Means

Because no chemical bonds are formed, the components of a mixture can be separated using physical methods. These methods rely on the different physical properties of the constituents. Common separation techniques include:

• Evaporation (e.g., separating salt from water)
• Filtration (e.g., separating sand from water)
• Magnetism (e.g., separating iron filings from sand)