Chapter 16: Lyophilic Colloids

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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?

Change in concentration and distance traveled Signup and view all the answers

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

Lyophilic colloids Signup and view all the answers

How are lyophilic colloidal sols usually obtained?

By dissolving the material in the solvent being used 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?

Solvation Signup and view all the answers

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

Gelatin and acacia Signup and view all the answers

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

Diffusion occurs in decreasing concentration of diffusion Signup and view all the answers

Which particles diffuse faster in a given media?

Molecular Signup and view all the answers

What is the relationship between osmosis and diffusion?

Osmosis involves transfer of solvent while diffusion involves passage of solute Signup and view all the answers

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

The osmotic pressure of a dilute colloidal solution Signup and view all the answers

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

Diffusion occurs in decreasing concentration of the diffusing material Signup and view all the answers

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

The osmotic pressure of a dilute colloidal solution Signup and view all the answers

In which type of media do smaller particles diffuse faster?

Molecular media Signup and view all the answers

What is the main action involved in osmosis?

Transfer of only the solvent Signup and view all the answers

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

Particle size Signup and view all the answers

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

A. molecular dispersions, B. colloidal dispersions, C. atomic dispersions Signup and view all the answers

What is the size range assigned to colloidal dispersions?

1 - 1000 nm Signup and view all the answers

What is the dispersed material in dispersed systems?

Dispersed phase Signup and view all the answers

What characterizes lyophobic colloids?

They have little attraction for the dispersion medium. Signup and view all the answers

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

Water Signup and view all the answers

What is a characteristic of association or amphiphilic colloids?

They are characterized by having two distinct regions of opposing solution affinities within the same molecule or ion. Signup and view all the answers

What type of particles are generally found in lyophobic colloids?

Inorganic particles Signup and view all the answers

Which characteristic best describes colloidal dispersion based on particle size?

Visible under a normal microscope Signup and view all the answers

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

Dialysis through a semipermeable membrane Signup and view all the answers

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

Non-polar solvents Signup and view all the answers

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

From 1 nm to 0.5 µm Signup and view all the answers

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

Particle size, viscosity, and density difference between particles and dispersion medium 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?

0.5 µm 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?

Ultracentrifuge 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?

Brownian movement 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?

Agglomeration Signup and view all the answers

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

Lyophilic Signup and view all the answers

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

Viscosity is not greatly increased because the particles tend to be unsolvated and symmetric 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?

Salting out 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?

Association (Amphiphilic) 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?

Gel formation Signup and view all the answers

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

Instability due to neutralization of the charge on the particles 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?

Salting out 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?

The velocity increases Signup and view all the answers

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

Agglomeration 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?

Neutralization Signup and view all the answers

Chapter 16: Lyophilic Colloids

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Questions and Answers

What is the main cause of Brownian motion?

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

What is the main driving force behind diffusion?

What does Fick's first law relate to?

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

How are lyophilic colloidal sols usually obtained?

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

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

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

Which particles diffuse faster in a given media?

What is the relationship between osmosis and diffusion?

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

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

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

In which type of media do smaller particles diffuse faster?

What is the main action involved in osmosis?

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

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

What is the size range assigned to colloidal dispersions?

What is the dispersed material in dispersed systems?

What characterizes lyophobic colloids?

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

What is a characteristic of association or amphiphilic colloids?

What type of particles are generally found in lyophobic colloids?

Which characteristic best describes colloidal dispersion based on particle size?

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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