Differentiate pure substance and mixture?

A pure substance is a substance that is made up of only one type of particle, such as an element or a compound. It has a fixed composition and distinct properties. Examples of pure substances include water, salt, and gold.

On the other hand, a mixture is a combination of two or more substances that are physically combined but not chemically bonded. Mixtures can be homogeneous (uniform composition throughout) or heterogeneous (non-uniform composition). Examples of mixtures include air, saltwater, and trail mix.

In summary, the main difference between a pure substance and a mixture is that a pure substance has a fixed composition and distinct properties, while a mixture is a combination of two or more substances that are physically combined.

Pure Substance:

- A substance that has a definite and constant composition throughout, both physically and chemically.
- Consists of only one type of molecule or atom.
- Examples: water, pure gold, helium gas

Mixture:

- A combination of two or more pure substances that retain their individual chemical identities.
- Can be physical or chemical.
- Components can be present in varying proportions.

Key Differences:

| Feature | Pure Substance | Mixture |
|---|---|---|
| Composition | Definite and constant | Variable |
| Chemical Identity | Single type of molecule or atom | Multiple types of molecules or atoms |
| Physical State | Can exist in any physical state (solid, liquid, gas) | Can exist in multiple physical states |
| Separation | Can be separated into its components only by chemical means | Can be separated into its components by physical means (e.g., filtration, distillation) |
| Properties | Well-defined and characteristic of the pure substance | Dependent on the composition and proportions of components |
| Example | Water, salt | Saltwater, air |

Types of Mixtures:

Homogeneous Mixtures:

- Appear uniform throughout.
- Components are evenly distributed and cannot be distinguished.
- Examples: saltwater, air

Heterogeneous Mixtures:

- Do not appear uniform.
- Components are not evenly distributed and can be visually distinguished.
- Examples: sand and water, salad, soil