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Big Picture — Classifying and Separating
Mixtures: Classify, then Separate
A mixture
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Classify it
Solution, suspension or colloid.
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Pick a method
Use a property like size, density, solubility or boiling point.
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Pure substances
Which Method Suits Which Mixture?
How do we separate mixtures?
Separation
Method fits the mixture
1. Homogeneous mixtures
Parts are dissolved
Example:
Crystallization
Distillation
Chromatography
2. Heterogeneous mixtures
Parts stay separate
Example:
Separating funnel
Sublimation
Centrifugation
Mind Map of the Chapter
Classifying mixtures
Homogeneous or heterogeneous; solutions, suspensions or colloids.
Concentration
Expressed as % m/m, % m/v or % v/v.
Crystallization
Gets a pure solid from its saturated solution.
Distillation
Separates miscible liquids differing by 25 °C or more.
Chromatography
Separates by different rates of movement on paper.
Separating funnel
Separates immiscible liquids by density.
Sublimation
Solid to vapour without melting; deposition is the reverse.
Centrifugation & coagulation
Spin or clump particles to separate them.
Tyndall effect
Colloids and suspensions scatter light.
Key Terms
- Solution
- A homogeneous mixture, uniform throughout.
- Solute / Solvent
- The dissolved substance / the dissolving substance.
- Concentration
- Amount of solute in a given amount of solvent or solution.
- Solubility
- The most solute that dissolves at a given temperature.
- Saturated solution
- One that can dissolve no more solute at that temperature.
- Crystallization
- Forming pure crystals from a saturated solution.
- Distillation
- Separating miscible liquids by boiling and condensing.
- Fractional distillation
- Separating liquids with small boiling-point gaps.
- Paper chromatography
- Separating a mixture by movement on paper.
- Immiscible liquids
- Liquids that do not mix and form layers.
- Sublimation / Deposition
- Solid to vapour / vapour to solid, skipping liquid.
- Alloy
- A homogeneous mixture of metals.
- Suspension
- A heterogeneous mixture with visible particles.
- Centrifugation
- Spinning to settle heavier particles.
- Coagulation
- Clumping fine particles with a coagulant.
- Colloid
- A mixture between a solution and a suspension.
- Tyndall effect
- Scattering of light by particles.
