Chapter 16: Lyophilic Colloids

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Listen to an AI-generated conversation about this lesson
Download our mobile app to listen on the go
Get App

Questions and Answers

What is the main cause of Brownian motion?

  • Electric charge
  • Thermal bombardment (correct)
  • External application of force
  • Gravitational force

How does the velocity of particles change with decreasing particle size?

  • Remains constant
  • Decreases
  • Increases (correct)
  • Stops completely

What is the main driving force behind diffusion?

  • Gravitational force
  • Applied external force
  • Brownian movement (correct)
  • Electrically induced motion

What does Fick's first law relate to?

<p>Change in concentration and distance traveled (A)</p>
Signup and view all the answers

What type of colloids are systems containing colloidal particles that interact significantly with the dispersion medium?

<p>Lyophilic colloids (B)</p>
Signup and view all the answers

How are lyophilic colloidal sols usually obtained?

<p>By dissolving the material in the solvent being used (A)</p>
Signup and view all the answers

What is the term for the attachment of solvent molecules to the molecules of the dispersed phase in hydrophilic colloids?

<p>Solvation (C)</p>
Signup and view all the answers

Which of the following materials produce lyophilic colloids in aqueous dispersion media?

<p>Gelatin and acacia (D)</p>
Signup and view all the answers

What does the negative sign in the equation for diffusion signify?

<p>Diffusion occurs in decreasing concentration of diffusion (D)</p>
Signup and view all the answers

Which particles diffuse faster in a given media?

<p>Molecular (D)</p>
Signup and view all the answers

What is the relationship between osmosis and diffusion?

<p>Osmosis involves transfer of solvent while diffusion involves passage of solute (D)</p>
Signup and view all the answers

What does the van't Hoff equation π = cRT describe?

<p>The osmotic pressure of a dilute colloidal solution (D)</p>
Signup and view all the answers

What does the negative sign in the equation for diffusion signify?

<p>Diffusion occurs in decreasing concentration of the diffusing material (D)</p>
Signup and view all the answers

What is the van't Hoff equation used to calculate?

<p>The osmotic pressure of a dilute colloidal solution (B)</p>
Signup and view all the answers

In which type of media do smaller particles diffuse faster?

<p>Molecular media (D)</p>
Signup and view all the answers

What is the main action involved in osmosis?

<p>Transfer of only the solvent (A)</p>
Signup and view all the answers

What is the basis of classifying dispersed systems according to the mean particle diameter of the dispersed material?

<p>Particle size (C)</p>
Signup and view all the answers

Which types of dispersed systems are generally considered based on the size of the dispersed phase?

<p>A. molecular dispersions, B. colloidal dispersions, C. atomic dispersions (C)</p>
Signup and view all the answers

What is the size range assigned to colloidal dispersions?

<p>1 - 1000 nm (A)</p>
Signup and view all the answers

What is the dispersed material in dispersed systems?

<p>Dispersed phase (C)</p>
Signup and view all the answers

What characterizes lyophobic colloids?

<p>They have little attraction for the dispersion medium. (D)</p>
Signup and view all the answers

In which dispersion medium may a material form a lyophilic colloidal system?

<p>Water (C)</p>
Signup and view all the answers

What is a characteristic of association or amphiphilic colloids?

<p>They are characterized by having two distinct regions of opposing solution affinities within the same molecule or ion. (A)</p>
Signup and view all the answers

What type of particles are generally found in lyophobic colloids?

<p>Inorganic particles (C)</p>
Signup and view all the answers

Which characteristic best describes colloidal dispersion based on particle size?

<p>Visible under a normal microscope (A)</p>
Signup and view all the answers

What technique can be used to separate colloidal particles from molecular particles?

<p>Dialysis through a semipermeable membrane (C)</p>
Signup and view all the answers

Which type of dispersion medium allows the formation of lyophobic colloidal systems?

<p>Non-polar solvents (D)</p>
Signup and view all the answers

What is the size range assigned to colloidal dispersions based on the text?

<p>From 1 nm to 0.5 µm (D)</p>
Signup and view all the answers

What are the factors affecting the sedimentation of particles in a dispersion medium?

<p>Particle size, viscosity, and density difference between particles and dispersion medium (A)</p>
Signup and view all the answers

What is the lower size limit of particles obeying Stokes's equation when subjected only to the force of gravity?

<p>0.5 µm (C)</p>
Signup and view all the answers

What device is used to produce a force one million times that of gravity to bring about the sedimentation of colloidal particles?

<p>Ultracentrifuge (A)</p>
Signup and view all the answers

What promotes mixing instead of sedimentation due to gravity for particles below the lower size limit obeying Stokes's equation?

<p>Brownian movement (A)</p>
Signup and view all the answers

What is the term for the process in which dispersed particles come together to form aggregates over a narrow concentration range?

<p>Agglomeration (C)</p>
Signup and view all the answers

In which type of colloidal dispersion would the diameter of each micelle be approximately 50 Ã…?

<p>Lyophilic (B)</p>
Signup and view all the answers

What is the main effect on the viscosity of the dispersion medium when lyophobic colloidal particles are present?

<p>Viscosity is not greatly increased because the particles tend to be unsolvated and symmetric (D)</p>
Signup and view all the answers

What is the term for the primary cause of the desolvation of lyophilic molecules in the presence of high concentrations of very soluble electrolytes?

<p>Salting out (B)</p>
Signup and view all the answers

In which type of dispersion system does the critical micelle concentration decrease with the addition of electrolytes in aqueous solutions?

<p>Association (Amphiphilic) (C)</p>
Signup and view all the answers

What is the term for the process where a sol may become a gel at sufficiently high concentrations of dispersed phase?

<p>Gel formation (B)</p>
Signup and view all the answers

What property generally characterizes lyophobic colloids in the presence of electrolytes?

<p>Instability due to neutralization of the charge on the particles (A)</p>
Signup and view all the answers

What is the term for when colloidal aggregates are formed spontaneously when the concentration of amphiphile exceeds a certain value?

<p>Salting out (B)</p>
Signup and view all the answers

What happens to the velocity of particles as micelles increase in number and become asymmetric in an association (amphiphilic) dispersion?

<p>The velocity increases (D)</p>
Signup and view all the answers

What is the term for when dispersed particles come together to form aggregates over a narrow concentration range?

<p>Agglomeration (A)</p>
Signup and view all the answers

What is the term for the process that causes lyophobic dispersions to be unstable in the presence of even small concentrations of electrolytes?

<p>Neutralization (D)</p>
Signup and view all the answers

Flashcards are hidden until you start studying

Related Documents

More Like This

Types of Colloids: Lyophilic vs. Lyophobic
24 questions
Introduction to Colloidal Dispersions
29 questions
Colloidal Dispersions Overview
30 questions
Colloidal Dispersions Overview
91 questions

Colloidal Dispersions Overview

ExemplaryBlackberryBush avatar
ExemplaryBlackberryBush
Use Quizgecko on...
Browser
Browser