50 Questions
What is the interfacial tension between water and oleic acid as given in the text?
15.6 dyne/cm
When will spreading occur according to the text?
Initially
What happens after the initial spreading based on the text?
A lens will form
In the given scenario, what would prevent a lens from forming?
Continuous spreading
What is the significance of the interfacial tension value provided in the text?
Determines the behavior of water and oleic acid at their interface
What is necessary to resuspend and redisperse particles?
Overcome forces
Which action facilitates the process of resuspending and redispersing particles?
Applying more force
What is the main challenge in resuspending and redispersing particles?
Overcoming existing forces
What role do forces play in the process of resuspending and redispersing particles?
They need to be overcome
Why is overcoming forces crucial in the resuspension and redispersion of particles?
To break particle aggregates
Why do the majority of particles dispersed in water acquire a negative charge?
Due to preferential adsorption of the hydroxyl ion
Which ion is more hydrated, leading to its preference to be in the bulk of the aqueous medium?
Hydronium ion
What is the primary reason for hydroxyl ions to be adsorbed at the surface of particles?
They are less hydrated than hydronium ions
What leads to the charges on particles according to the text?
Ionization of groups at the particle surface
Which ion has a greater tendency to be in the bulk of the aqueous medium based on its hydration level?
Hydronium ion
What happens when the zeta potential is reduced below a certain value?
Attractions forces exceed repulsive forces
How do particles behave when the zeta potential is lowered beyond a specific threshold?
They come closer together
What is the consequence of attractive forces exceeding repulsive forces in a system?
Particles aggregate
Which statement is true when the zeta potential falls below a system-dependent threshold?
Particles start coming together
What occurs if the attractive forces between particles are stronger than the repulsive forces in a system?
Particles aggregate
What is the purpose of the curves shown in the liquid phase?
To represent ions or molecules
Which characteristic is NOT depicted by the curves in the liquid phase?
Shape
What does the term 'liquid phase' refer to in this context?
A state of matter with particles that flow
What does the presence of curves suggest about the ions or molecules in the liquid phase?
They are interacting with each other
Which property of ions or molecules is likely NOT indicated by the curves in the liquid phase?
Stability
What term is customarily used when referring to either a gas-solid or a gas-liquid interface?
Surface
In pharmacy, which of the following is an example of practical significance related to solid-solid interfaces?
Flow of particles
What is a key application of solid-solid interfaces in pharmacy according to the text?
Preparation of layered tablets
Which of the following is NOT mentioned as a practical significance of solid-solid interfaces in pharmacy in the text?
Zeta potential threshold
When referring to interfaces, what does the term 'surface' encompass according to the text?
Gas-liquid interfaces
What happens to the excess anions in the equilibrium situation described in the text?
Approach the surface
How are the remainders of excess anions distributed as one moves away from the charged surface?
In decreasing amounts
What term best describes the distribution of excess anions in the equilibrium scenario mentioned?
Radial dispersion
What characterizes the equilibrium situation established with respect to excess anions near the charged surface?
Radial migration
In the described equilibrium, why do some of the excess anions approach the surface?
As a result of attractive forces
What is the final spreading coefficient after equilibration?
33.4 dynes/cm
What does a greater spreading coefficient value indicate in this context?
Increased adhesion between the liquid and solid
How would the system behave if the final spreading coefficient was negative?
Spreading would cease and the liquid would retract from the solid surface
In this scenario, what would a decrease in the solid surface tension lead to?
Increase in spreading coefficient
What effect would an increase in both γS′ and γL′ have on the spreading coefficient?
No effect on spreading coefficient
What is the mechanism of cell death mentioned in the text?
Loss of essential materials
Which type of organisms are susceptible to the action of cationic quaternary compounds according to the text?
Both gram-positive and gram-negative organisms
What property of interfaces is discussed in Chapter 15 of Interfacial Phenomena?
Electric properties
What is the role of charge on the surface of a particle in interfacial phenomena?
Facilitate resuspension
What results in the death of cells according to the text?
Loss of essential materials
Which type of particles are described as settling rapidly, not forming a cake, and easily resuspended?
Flocculated particles
What is a characteristic of flocculated particles when the zeta potential is decreased beyond a specific threshold?
They settle slowly
Why do flocculated particles settle rapidly?
Weak bonding forces
What happens to flocculated particles in terms of cake formation compared to agglomerated particles?
Agglomerated particles form a cake, flocculated particles do not
What distinguishes flocculated particles from colloidal particles?
Formation of a cake
Explore the phenomenon of spreading between γ (gamma) water and oleic acid with a surface tension of 15.6 dyne/cm. Learn how the initial spreading transforms into a lens formation over time in Chapter 15's study of Interfacial Phenomena.
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