Pure Substance
* Definition: A pure substance is a material made up of only one type of particle.
* Composition: The composition of a pure substance is fixed and uniform throughout.
* Examples: Water (H₂O), gold (Au), sugar (C₁₂H₂₂O₁₁), salt (NaCl)
* Properties: Pure substances have unique and consistent physical and chemical properties.
Mixture
* Definition: A mixture is a combination of two or more substances where each substance retains its own properties.
* Composition: The composition of a mixture can vary. It's not uniform throughout.
* Examples: Saltwater (salt and water), air (nitrogen, oxygen, and other gases), soil (sand, clay, organic matter), salad (lettuce, tomatoes, cucumbers, etc.)
* Properties: The properties of a mixture are often a blend of the properties of the individual substances.
Key Differences:
* Composition: Pure substances have a fixed composition, while mixtures have a variable composition.
* Uniformity: Pure substances are uniform throughout, while mixtures can be heterogeneous (non-uniform) or homogeneous (uniform).
* Separation: Components of a mixture can often be separated by physical methods (like filtration, evaporation, or magnetism), while the components of a pure substance cannot.
Here's a simple analogy:
Imagine a box of Legos.
* Pure substance: A box filled with only red Legos.
* Mixture: A box filled with Legos of different colors (red, blue, green).
