A mixture is a substance formed by the physical combination of two or more substances (elements or compounds) in any proportion, where
- The substances do not combine chemically.
- Each component retains its own properties.
- The components can be separated by physical methods.
In a mixture, substances are simply mixed together physically.
- No new substance is formed.
- No chemical reaction takes place.
- The composition may vary.
Examples: Salt and water, Air, Sugar solution, Soil
Properties
- Components are not chemically bonded.
- Substances can be mixed in any proportion.
- Components retain their original identity and properties.
- Mixtures can be separated by physical methods like filtration, Evaporation, distillation, and Magnetic separation
- Melting point and boiling point are not fixed.
- No chemical change occurs during formation.
- Can exist in solid, liquid, or gaseous states.
- Energy change is usually very small or absent.
Examples
- Smog → Smoke + Fog
- Cement mixture → Sand + Water + Gravel
- Seawater → Water + Salt
- Soil → Minerals + Air + Water + Organic matter
- Blood → Plasma + RBC + WBC + Platelets
- Gasoline → Mixture of hydrocarbons
- Brass (Alloy) → Copper + Zinc
- Nichrome (Alloy) → Nickel + Chromium + Iron
- Bleach solution → Water + Sodium hypochlorite
- Air → Nitrogen + Oxygen + Carbon dioxide + other gases
Types
Homogeneous Mixture
- A mixture in which the components are uniformly distributed throughout the mixture and the composition is the same in every part.
- “Homo” means same.
- example: Salt and Water, Sugar and Water, Alcohol and Water, etc.
Properties
- No visible boundaries between components.
- Cannot see different parts with the naked eye.
- Particle size is very small (less than 1 nm).
- Do not show the Tyndall effect.
- Cannot be separated by simple filtration.
- Appear as a single phase.
Examples: Air, Soft Drink, Cooking Gas, Coffee, cement, vinegar, etc.
Heterogeneous Mixture
- A mixture in which the components are not uniformly distributed and can be seen separately.
- “Hetero” means different.
- Examples: Sand and water, Oil and water, Sugar and salt, Ice in water, soil.
Properties
- Non-uniform distribution.
- Different parts can be seen clearly.
- Two or more phases present.
- Boundaries are visible.
- Particle size is larger (generally more than 1 nm).
- May show the Tyndall effect (especially colloids).
- Can often be separated easily by filtration or decantation.
Examples: Granite, Iron ore, Milk and cereal, Rice and beans, Water and sand, Water and oil