PSE 322 QUIZ 5 QUESTIONS AND ANSWERS
An emulsion half-life of 10,000,000,000,000 years was predicted for what value of
energy barrier (in kT units)? - Answers :50 kT
Where is the zeta potential defined? - Answers :At the slip plane
What two tendencies combine to create an atmosphere-like distribution of counter-ions
in the Guoy diffuse layer at a charged surface in aqueous solution? - Answers :Thermal
(Brownian) diffusion and electrostatic attraction
What is being measured if particles in a suspension are subjected to a known electrical
field and observed with a microscope and stopwatch? - Answers :Zeta potential
(microelectrophoresis)
What kind of problem can be caused by high water hardness during dilution of a
suspension of titanium oxide (TiO2) particles? - Answers :Coagulation and deposits
What item, if present on fibrils at the fiber surface, would give them a negative charge
so that they would tend to repel each other and stick out in the presence of water? -
Answers :Hemicellulose
What happens at the Stern layer? - Answers :Counter-ions are immediately on a
surface of opposite charge.
To predict the rate of collisions between particles having the same sign of charge, what
kind of barriers must be considered in order to obtain accurate results? - Answers
:Energy
What can be expected when the absolute value of zeta potential in a suspension is very
high? - Answers :The suspension will be stable due to electrostatic repulsion between
particles.
Which of the following ions will have a higher affinity for the surface of a high-yield pulp
fiber that has a relatively high level of carboxylic acid groups? - Answers :Calcium
Which of the following can be expected to contribute to steric stabilization? - Answers
:Block copolymer with hydrophobic and hydrophilic groups
In the Schultze-Hardy rule, what parameter is raised to the negative sixth power? -
Answers :Valence
What is the term used for hair-like cellulose strands at surface of cellulosic fibers,
especially after refining? - Answers :Fibrils
An emulsion half-life of 10,000,000,000,000 years was predicted for what value of
energy barrier (in kT units)? - Answers :50 kT
Where is the zeta potential defined? - Answers :At the slip plane
What two tendencies combine to create an atmosphere-like distribution of counter-ions
in the Guoy diffuse layer at a charged surface in aqueous solution? - Answers :Thermal
(Brownian) diffusion and electrostatic attraction
What is being measured if particles in a suspension are subjected to a known electrical
field and observed with a microscope and stopwatch? - Answers :Zeta potential
(microelectrophoresis)
What kind of problem can be caused by high water hardness during dilution of a
suspension of titanium oxide (TiO2) particles? - Answers :Coagulation and deposits
What item, if present on fibrils at the fiber surface, would give them a negative charge
so that they would tend to repel each other and stick out in the presence of water? -
Answers :Hemicellulose
What happens at the Stern layer? - Answers :Counter-ions are immediately on a
surface of opposite charge.
To predict the rate of collisions between particles having the same sign of charge, what
kind of barriers must be considered in order to obtain accurate results? - Answers
:Energy
What can be expected when the absolute value of zeta potential in a suspension is very
high? - Answers :The suspension will be stable due to electrostatic repulsion between
particles.
Which of the following ions will have a higher affinity for the surface of a high-yield pulp
fiber that has a relatively high level of carboxylic acid groups? - Answers :Calcium
Which of the following can be expected to contribute to steric stabilization? - Answers
:Block copolymer with hydrophobic and hydrophilic groups
In the Schultze-Hardy rule, what parameter is raised to the negative sixth power? -
Answers :Valence
What is the term used for hair-like cellulose strands at surface of cellulosic fibers,
especially after refining? - Answers :Fibrils
