Mixtures

A physical combination of two or more substances.

• Constituents retain their chemical properties
• Can be separated by physical methods

Types of Mixtures

1. Solid + Liquid mixture
   • Example: sugar in water, salt in oil
2. Liquid + Liquid mixture
   • Immiscible (do not mix): water + oil
   • Miscible (mix uniformly): water + alcohol
3. Solid + Solid mixture
   • Example: clay and sand, alloys
4. Solid + Gas mixture
   • Example: smoke, dust, foam mattress
5. Liquid + Gas mixture
   • Example: fog, mist, clouds
6. Gas + Gas mixture
   • Example: air

Classes of Mixtures

• Homogeneous mixture → uniform composition (e.g., salt + water, alcohol + water)
• Heterogeneous mixture → non-uniform composition (e.g., sand + water, oil + water)

Differences Between Homogeneous and Heterogeneous Mixtures

Solute

A substance that dissolves in a solvent.

• Soluble: sugar, salt, ethanol
• Insoluble: sand, chalk, oil

Factors Affecting Dissolution

1. Smaller particle size → faster
2. Stirring → speeds mixing
3. Heating → increases rate

Solvent

The substance in which solutes dissolve.

• Usually present in larger quantity
• Water is called the universal solvent

Examples

Differences Between Solvent and Solute

Solution

A homogeneous mixture of two or more substances.

• Solute dissolves completely
• Constituents do not separate

Examples:

• Salt + water
• Sugar + water
• Vinegar + water
• Alcohol + water

Types of Solutions

• Dilute solution → less solute
• Concentrated solution → more solute but can still dissolve more
• Saturated solution → maximum solute dissolved

Suspension

A heterogeneous mixture where solute does not dissolve in the solvent.

• Particles visible to the naked eye
• Particles settle when undisturbed

Examples:

• Gari + water
• Muddy water
• Oil + water

Differences Between Solution and Suspension

Colloid

A mixture in which one substance is permanently dispersed in another medium.

• Stable, particles do not dissolve
• Too small to see with naked eye
• Appears homogeneous but is heterogeneous

Examples:

• Milk
• Starch in water
• Blood
• Egg
• Toothpaste

Differences Between Colloid and Suspension