Lec.8 Eman

Question 1

What are dispersed systems composed of?
a) Particles of atomic and molecular dimensions
b) Particles measured in millimeters
c) Both a) and b)
d) None of the above

Answer 1

c) Both a) and b)

Question 2

How can dispersed systems be classified?
a) Based on the nature of the dispersed material
b) Based on the size of the dispersed phase
c) Based on the color of the dispersion medium
d) Based on the viscosity of the continuous phase

Answer 2

b) Based on the size of the dispersed phase

Question 3

What are the three types of dispersed systems based on the size of the dispersed phase?
a) Nano dispersions, micro dispersions, and macro dispersions
b) Molecular dispersions, colloidal dispersions, and coarse dispersions
c) Liquid dispersions, solid dispersions, and gas dispersions
d) Emulsions, suspensions, and solutions

Answer 3

b) Molecular dispersions, colloidal dispersions, and coarse dispersions

Question 4

Which class of dispersed systems has the smallest particle size?
a) Molecular dispersions
b) Colloidal dispersions
c) Coarse dispersions
d) They all have similar particle sizes

Answer 4

a) Molecular dispersions

Question 5

What is the technique called that uses a semipermeable membrane to separate colloidal particles from molecular particles?
a) Filtration
b) Dialysis
c) Centrifugation
d) Distillation

Answer 5

b) Dialysis

Question 6

Where does dialysis occur in vivo?
a) Within the capillary system
b) Within the tissue fluids
c) Within the blood
d) Within the artificial kidney

Answer 6

a) Within the capillary system

Question 7

What components of the blood remain within the capillary system during dialysis?
a) Ions and small molecules
b) Colloidal components
c) Both a) and b)
d) None of the above

Answer 7

b) Colloidal components

Question 8

What is the purpose of the artificial kidney in the dialysis process?
a) To remove colloidal components from the blood
b) To remove high-molecular-weight impurities from the body
c) To remove low-molecular-weight impurities from the body
d) To separate molecular particles from colloidal particles

Answer 8

c) To remove low-molecular-weight impurities from the body

Question 9

The shape of particles in a colloidal dispersion affects:
a) Specific surface area
b) Particle size
c) Viscosity
d) Density

Answer 9

a) Specific surface area

Question 10

Why is the shape of particles in a colloidal dispersion important?
a) It determines the color of the dispersion.
b) It affects the particle size distribution.
c) It influences the specific surface area and attractive forces.
d) It determines the density of the dispersion.

Answer 10

c) It influences the specific surface area and attractive forces.

Question 11

What happens to the specific surface area as the particle shape becomes more extended?
a) It decreases.
b) It remains constant.
c) It increases.
d) It depends on the dispersion medium.

Answer 11

c) It increases.

Question 12

What do attractive forces between particles in a colloidal dispersion depend on?
a) Particle size
b) Particle shape
c) Dispersion medium
d) Both a) and c)

Answer 12

d) Both a) and c)

Question 13

What are colloidal systems that interact with the dispersion medium referred to as?
a) Lyophilic colloids
b) Lyophobic colloids
c) Hydrophilic colloids
d) Lipophilic colloids

Answer 13

a) Lyophilic colloids

Question 14

How are lyophilic colloidal sols usually obtained?
a) By dissolving the material in the solvent
b) By chemical reaction between the dispersed phase and dispersion medium
c) By physical grinding of the particles
d) By heat treatment of the material

Answer 14

a) By dissolving the material in the solvent

Question 15

What term is used to describe the attachment of solvent molecules to the molecules of the dispersed phase in hydrophilic colloids?
a) Hydration
b) Solvation
c) Adsorption
d) Coagulation

Answer 15

a) Hydration

Question 16

Which class of colloids is composed of materials with little attraction for the dispersion medium?
a) Lyophilic colloids
b) Lyophobic colloids
c) Hydrophilic colloids
d) Lipophilic colloids

Answer 16

b) Lyophobic colloids

Question 17

How are lyophobic colloids generally prepared?
a) By dissolving the material in the solvent
b) By chemical reaction between the dispersed phase and dispersion medium
c) By physical grinding of the particles
d) By special methods

Answer 17

d) By special methods

Question 18

What are amphiphilic colloids characterized by?
a) Having a single distinct region of solution affinity
b) Having two distinct regions of opposing solution affinities
c) Having high concentrations in a liquid medium
d) Having large aggregate sizes

Answer 18

b) Having two distinct regions of opposing solution affinities

Question 19

At what concentration do amphiphiles exist separately and are subcolloidal in size?
a) Low concentrations
b) High concentrations
c) Intermediate concentrations
d) Concentrations that vary depending on the specific amphiphile

Answer 19

a) Low concentrations

Question 20

What is the term used to describe the aggregation of amphiphiles at higher concentrations?
a) Dissolution
b) Micellization
c) Precipitation
d) Emulsification

Answer 20

b) Micellization

Question 21

What are the aggregates containing 50 or more monomers called?
a) Agglomerates
b) Micelles
c) Polymers
d) Nanoparticles

Answer 21

b) Micelles

Question 22

Why are compounds that form micelles referred to as association colloids?
a) Because they associate with other colloidal particles
b) Because their association leads to increased solubility
c) Because they have an association with a specific type of solvent
d) Because their micelles lie within the size range of colloidal particles

Answer 22

d) Because their micelles lie within the size range of colloidal particles