1. Matter
* Definition: Anything that has mass and takes up space.
2. Mixtures
* Definition: A combination of two or more substances where each substance retains its own properties.
* Characteristics:
* Components can be physically separated.
* No fixed composition (ratios of components can vary).
* Components retain their individual properties.
* Types:
* Homogeneous mixtures: Uniform composition throughout (e.g., saltwater, air).
* Heterogeneous mixtures: Non-uniform composition (e.g., sand and water, oil and water).
3. Pure Substances
* Definition: A substance with a fixed composition and properties.
* Characteristics:
* Components cannot be separated by physical means.
* Have a definite and consistent composition.
* Types:
* Elements: Simplest form of matter. Cannot be broken down into simpler substances by ordinary chemical means. (e.g., gold, oxygen, carbon).
* Compounds: Formed when two or more elements chemically combine in a fixed ratio. (e.g., water (H₂O), salt (NaCl)).
Here's a simple way to visualize the classification:
```
Matter
|
--------------------------
| |
Mixtures Pure Substances
| |
--------------------- ------------------
| | | |
Homogeneous Heterogeneous Elements Compounds
```
Key Differences:
* Mixtures: Components retain their individual properties and can be separated by physical means (filtration, evaporation, etc.).
* Pure Substances: Components are chemically bonded, resulting in new properties, and can only be separated by chemical means.
Examples:
* Mixture: A salad (lettuce, tomatoes, cucumbers) - Each ingredient retains its own properties.
* Pure Substance (Element): Gold (Au) - Cannot be broken down further.
* Pure Substance (Compound): Water (H₂O) - Two elements (hydrogen and oxygen) chemically combined, resulting in new properties (liquid at room temperature).
