Colloids & Suspensions
Colloids, Suspensions, and Their Comparison
I. Colloids
- A. Definition: Heterogeneous mixtures with solute particles larger than true solutions but not visible to naked eye
- B. Characteristics:
- 1. Particle size: 1-1000 nm
- 2. Remain dispersed without settling
- 3. Scatter light (Tyndall effect)
- C. Examples: Starch, albumin, soap solutions, blood, milk, ink, jelly, toothpaste
II. Suspensions
- A. Definition: Heterogeneous mixture of undissolved solid particles in a liquid medium
- B. Characteristics:
- 1. Particle size: < 1000 nm
- 2. Visible to naked eye
- 3. Settle over time
- C. Examples: Chalk in water, paints, milk of magnesia
III. Comparison of Solutions, Colloids, and Suspensions
| Characteristic | Solution | Colloid | Suspension |
|---|---|---|---|
| Homogeneity | Homogeneous | Heterogeneous | Heterogeneous |
| Particle size | < 1 nm | 1-1000 nm | > 1000 nm |
| Visibility | Not visible | Not visible | Visible |
| Filtration | Passes all filters | Passes normal filter, not ultra-filter | Cannot pass filters |
| Light scattering | No | Yes (Tyndall effect) | Yes |
| Separation | Does not separate | Does not separate | Separates when stationary |
| Example | Sea water | Milk | Muddy water |
IV. Key Points Summary
Summarizes main concepts from the provided content
V. Review Questions
Includes multiple-choice and short answer questions
VI. Think Tank and Project
- A. Analytical questions about solutions and colloids
- B. Poster project on forms of matter in everyday environment