PSE 322 Quiz 5 Question and answers
correctly solved 2025/2026
An emulsion half-life of 10,000,000,000,000 years was predicted for what value of energy barrier (in kT
units)? - correct answer ✔50 kT
Where is the zeta potential defined? - correct answer ✔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? - correct answer ✔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? - correct answer ✔Zeta potential (microelectrophoresis)
What kind of problem can be caused by high water hardness during dilution of a suspension of titanium
oxide (TiO2) particles? - correct answer ✔Coagulation and deposits
What can be expected if the thickness of electrical double layers is decreased in a suspension? - correct
answer ✔The frequency of sticking collisions between particles is increased.
Suppose that a concentration of 0.1 mM is just enough to bring about coagulation when using the
divalent calcium ion. About what concentration will be needed in the case of monovalent sodium? (The
"carrot" symbol (^) means "raised to the power of".) - correct answer ✔0.1 mM x (1/2)^(-6) = 64 mM
Which component of wood tends to be the most hydrophobic? - correct answer ✔Lignin
What characteristic of wood extractives is generally true of all the wood extractives? - correct answer
✔Predominantly hydrophobic
, Which of the following components of cellulosic fiber materials have a surface-active character? -
correct answer ✔Fatty acids and resin acids
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? - correct answer
✔Hemicellulose
What happens at the Stern layer? - correct answer ✔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? - correct answer ✔Energy
What can be expected when the absolute value of zeta potential in a suspension is very high? - correct
answer ✔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? - correct answer ✔Calcium
Which of the following can be expected to contribute to steric stabilization? - correct answer ✔Block
copolymer with hydrophobic and hydrophilic groups
In the Schultze-Hardy rule, what parameter is raised to the negative sixth power? - correct answer
✔Valence
What is the term used for hair-like cellulose strands at surface of cellulosic fibers, especially after
refining? - correct answer ✔Fibrils
correctly solved 2025/2026
An emulsion half-life of 10,000,000,000,000 years was predicted for what value of energy barrier (in kT
units)? - correct answer ✔50 kT
Where is the zeta potential defined? - correct answer ✔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? - correct answer ✔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? - correct answer ✔Zeta potential (microelectrophoresis)
What kind of problem can be caused by high water hardness during dilution of a suspension of titanium
oxide (TiO2) particles? - correct answer ✔Coagulation and deposits
What can be expected if the thickness of electrical double layers is decreased in a suspension? - correct
answer ✔The frequency of sticking collisions between particles is increased.
Suppose that a concentration of 0.1 mM is just enough to bring about coagulation when using the
divalent calcium ion. About what concentration will be needed in the case of monovalent sodium? (The
"carrot" symbol (^) means "raised to the power of".) - correct answer ✔0.1 mM x (1/2)^(-6) = 64 mM
Which component of wood tends to be the most hydrophobic? - correct answer ✔Lignin
What characteristic of wood extractives is generally true of all the wood extractives? - correct answer
✔Predominantly hydrophobic
, Which of the following components of cellulosic fiber materials have a surface-active character? -
correct answer ✔Fatty acids and resin acids
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? - correct answer
✔Hemicellulose
What happens at the Stern layer? - correct answer ✔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? - correct answer ✔Energy
What can be expected when the absolute value of zeta potential in a suspension is very high? - correct
answer ✔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? - correct answer ✔Calcium
Which of the following can be expected to contribute to steric stabilization? - correct answer ✔Block
copolymer with hydrophobic and hydrophilic groups
In the Schultze-Hardy rule, what parameter is raised to the negative sixth power? - correct answer
✔Valence
What is the term used for hair-like cellulose strands at surface of cellulosic fibers, especially after
refining? - correct answer ✔Fibrils
