What is Suspension/Colloid?

Question 1

Definition of a suspension.

Answer 1

Non-homogenous systems in which solids are dispersed in liquids are called suspensions. A heterogenous mixture in which the solute particles do not dissolve but remain suspended throughout the bulk of the medium.

Question 2

List the properties of suspensions.

Answer 2

1. heterogeneous mixture
2. particles of a suspension can be seen by the naked eye
3. particles scatter a beam of light passing through it and make its path visible (shows Tyndall effect)
4. solute particles settle down when a suspension is left undisturbed.
5. suspension is unstable
6. solute particles can be separated from the mixture by the process of filtration.
7. when particles settle down, suspension breaks and it does not scatter light anymore.

Question 3

Define colloidal solution.

Answer 3

Particles of a colloid are uniformly spread throughout the solution. Smaller size of particles. It is a heterogeneous mixture.

Question 4

List the properties of a colloidal solution.

Answer 4

1. heterogeneous mixture
2. size of particles too small to be seen with the naked eye
3. big enough to scatter a beam of light passing through and make it visible.
4. do not settle down when left undisturbed.
5. cannot be separated from the mixture by filtration.
6. centrifugation can be used to separate colloidal particles.

Question 5

Differentiate between colloids and suspensions.

Answer 5

COLLOID
1. particle size between true solution and suspension
2. particles are uniformly distributed
3. heterogeneous mixture
4. cannot see particles with the naked eye
5. shows Tyndall Effect
6. don’t settle down when left undisturbed
7. stable solution.
8. eg. milk

SUSPENSION
1. particles bigger than colloid
2. can be seen with the naked eye
3. shows Tyndall Effect when particles are suspended
4. can be separated by filtration
5. unstable solution
6. eg. sand in water

Question 6

Give two examples of Tyndall Effect.

Answer 6

1. When a fine beam of light enters a room through a small hole. Happens due to the scattering of light by the particles of dust and smoke in the air.
2. When sunlight passes through the canopy of a dense forest. Mist contains tiny droplets of water, which act as particles of colloid dispersed in the air.

Question 7

What is a dispersed phase and a dispersing medium?

Answer 7

The components of a colloidal solution are dp and dm.
Dispersed phase - solute-like component or the dispersed particles in a colloid
Dispersing medium - component in which the dispersed phase is suspended

Question 8

DID YOU STUDY THE COMMON EXAMPLES OF COLLOIDS ON PAGE 18?

Answer 8

Yes