Separation Techniques

Key Definitions

• Chromatography: Separates mixtures soluble in the same solvent.
• Evaporation: Separates a solute and solvent, keeping the solute.
• Filtration: Separates insoluble solid and liquid mixtures.
  • Residue: Solid left in filter paper.
  • Filtrate: Liquid that passes through filter paper.
• Distillation: Separates a solute and solvent, keeping the solvent.
• Mixture: Substances together, but not chemically bonded.
• Solution: Mixture of two parts:
  • Solvent: Liquid that makes up most of the solution.
  • Solute: Substance that dissolves into the solvent.
• Solubility: How much solute dissolves in a solvent at a specific temperature.
• Saturated: No more solute can dissolve in the solvent.

Chromatography

1. Mixture placed on paper in a solvent.
2. Solvent moves up, separating constituents, producing a chromatogram.

Evaporation

1. Solution heated until solvent evaporates.
2. Solute left as a solid.

Filtration

1. Filter paper has small holes.
2. Liquid particles fit through holes.
3. Solid particles are too big and are held back.

Distillation

1. Solution heated, solvent evaporates.
2. Gas cools and condenses, turning back into a liquid for collection.

Mixtures vs. Compounds

• Mixtures: Substances not chemically bonded, easy to separate, amounts can vary.
• Compounds: Substances chemically bonded.

Pure vs. Impure Substances

• Pure Substance: Sharp melting point.
• Impure Substance (Mixture): Range of melting temperatures.

Solutions

• Solute particles break away and move into the solvent.

Solubility

• Different solutes have different solubilities in different solvents.
• Increasing temperature often increases solubility.
• Soluble substances can dissolve; insoluble substances cannot.