Colloids (11.5)

Question 1

What is suspensions?

Answer 1

Heterogeneous mixtures composed of relatively large particles that that are visible (or that it can be seen with magnifying glasses).

Question 2

Define colloids/colloidal dispersion.

Answer 2

A mixture where tiny particles are spread out evenly throughout another substance, but they are not dissolved in it.

• Tiny balls that are big enough that you can’t see them individually. But they are small enough to stay evenly spread out without settling to the bottom.

Question 3

What is Tyndall effect?

Answer 3

Particles in a colloid are large enough to scatter light, which causes the liquid to look cloudy or opaque.

Question 4

What is dispersed phase?

Answer 4

Part of a mixture where tiny particles or droplets are spread out.

Examples:
- Milk, the dispersed phase is the tiny fat droplets.
- Fog, the dispersed phase is the tiny water droplets in the air.

Question 5

Define dispersion medium.

Answer 5

The tiny particles or droplets is being held by another surrounding substance.

Examples:
- Milk, the dispersion medium is water (or liquid) that surrounds the fat droplets.
- In fog, the dispersion medium is the air that contains the tiny water droplets.

Question 6

Define emulsion.

Answer 6

A mixture where tiny droplets of one liquid are dispersed throughout another liquid. They are both immiscible (don’t mix well) but can be helped with an emulsifying agent.

Question 7

Define amphiphilic.

Answer 7

Molecule contains hydrophilic (water-attracting) and hydrophobic (water-repelling) parts. This allows molecule to interact with both water and oil, making it useful in forming mixtures like emulsions.

Question 8

What is an emulsifying agent?

Answer 8

Substance that helps mix two liquids that don’t mix well together by reducing the surface tension between them.

Question 9

Define gel in chemistry (colloids).

Answer 9

Liquid is spread throughout a solid-like substance, creating a thick, semi-solid structure.

Structure: liquid forms tiny droplets or networks within a solid-like matrix, giving it a gel-like consistency.