Lec.9 Eman

Question 1

What is the cause of Brownian motion in colloidal systems?
a) Gravitational force
b) Thermal bombardment by molecules of the dispersion medium
c) Applied external force
d) Electrical repulsion between particles

Answer 1

b) Thermal bombardment by molecules of the dispersion medium

Question 2

How does increasing the temperature affect Brownian motion?
a) Increases the velocity of particles
b) Decreases the velocity of particles
c) Halts the Brownian motion completely
d) Has no effect on Brownian motion

Answer 2

a) Increases the velocity of particles

Question 3

What is diffusion in colloidal systems?
a) The random movement of colloidal particles
b) The settling of particles due to gravity
c) The motion induced by an external force
d) The movement of particles from higher concentration to lower concentration

Answer 3

d) The movement of particles from higher concentration to lower concentration

Question 4

Which property of colloidal systems is directly related to Brownian motion?
a) Viscosity of the dispersion medium
b) Particle size
c) Concentration of particles
d) Electrical charge on particles

Answer 4

b) Particle size

Question 5

What is the main mechanism by which smaller particles diffuse faster in a given media?
a) Osmosis
b) Active transport
c) Brownian motion
d) Filtration

Answer 5

c) Brownian motion

Question 6

Which type of substances can pass through tortuous pores or channels, such as the skin?
a) Molecular substances only
b) Colloidal substances only
c) Coarse substances only
d) Both molecular and colloidal substances

Answer 6

d) Both molecular and colloidal substances

Question 7

What is the main driving force for passive diffusion?
a) Concentration gradient
b) Electrical potential
c) Osmotic pressure
d) Surface tension

Answer 7

a) Concentration gradient

Question 8

What is the main difference between osmosis and diffusion?
a) Osmosis involves the passage of solute, while diffusion involves the transfer of solvent.
b) Osmosis involves the transfer of solvent, while diffusion involves the passage of solute.
c) Osmosis requires an external force, while diffusion occurs spontaneously.
d) Osmosis occurs only in biological systems, while diffusion occurs in both biological and non-biological systems.

Answer 8

b) Osmosis involves the transfer of solvent, while diffusion involves the passage of solute.

Question 9

What information can the osmotic pressure provide about a colloid in a real solution?
a) The concentration of the colloid
b) The size of the colloid particles
c) The molecular weight of the colloid
d) The charge of the colloid particles

Answer 9

c) The molecular weight of the colloid

Question 10

What does the constant B in the pi/cg plot represent?
a) The concentration of the colloid
b) The size of the colloid particles
c) The interaction between the solvent and the solute
d) The osmotic pressure of the solution

Answer 10

c) The interaction between the solvent and the solute

Question 11

Which line of the r/cg plot represents a system with a high affinity between the solvent and the dispersed particles?
a) Line I (ideal system)
b) Line II (real system)
c) Line III (good solvent system)
d) The plot does not provide information about solvent affinity

Answer 11

c) Line III (good solvent system)

Question 12

In which line of the pi/cg plot is B equal to zero?
a) Line I (ideal system)
b) Line II (real system)
c) Line III (good solvent system)
d) B is never equal to zero

Answer 12

a) Line I (ideal system)