Methods for Separating Mixtures and Pure Substances

Heterogeneous Mixtures: Composite Nature

Heterogeneous mixtures consist of substances that do not mix uniformly, similar to water and oil. These can be separated using various physical methods:

• Solid-Solid Mixtures: Separated by magnetization (if one component is magnetic), manual sorting, or sieving (if particle sizes differ).
• Solid-Liquid Mixtures: Separated via sedimentation, decanting, centrifugation, or filtration.
• Immiscible Liquids: Separated using a separating funnel or normal settling based on density differences.

Homogeneous Mixtures and Solutions

Homogeneous mixtures have a uniform composition throughout. A solution is formed by two or more substances in variable proportions:

• Solvent: The component present in the largest quantity.
• Solute: The component present in the smaller quantity (e.g., salt in water).

Advanced Separation Techniques

Distillation

This process separates liquids based on different boiling points:

1. Heat the mixture until the liquid with the lower boiling point evaporates.
2. Condense the vapor using a refrigerant.

Evaporation and Crystallization

• Evaporation: Removing the liquid solvent to retain the solute.
• Crystallization: Recovering a solid dissolved in a liquid by cooling the solution or evaporating the solvent until the solid deposits at the bottom.

Pure Substances: Elements and Compounds

• Elements: Pure substances that cannot be decomposed into simpler substances (e.g., Iron, Carbon, Oxygen, Copper, Sodium, Chlorine).
• Compounds: Pure substances formed by two or more elements combined in fixed proportions.

Note: A substance formed by one element is a simple substance. Ozone (O3) is not considered a compound.