Podcast
Questions and Answers
What is the cause of non-wetting in a liquid-solid dispersion?
What is the cause of non-wetting in a liquid-solid dispersion?
- Insufficient uniform dispersion of solid particles (correct)
- Lack of gravitational effects
- Excessive uniform dispersion of solid particles
- Inadequate Brownian motion
What determines the stability of a suspension in a liquid?
What determines the stability of a suspension in a liquid?
- Size of the particles in the suspension
- Density of the liquid
- Temperature of the liquid
- Balance of attractive & repulsive interactions between particles (correct)
What type of forces lead to attraction between particles in a dispersion?
What type of forces lead to attraction between particles in a dispersion?
- Electrostatic forces
- Van der Waals forces (correct)
- Gravitational forces
- Magnetic forces
What leads to the thermodynamic instability of a system when particles are dispersed into a liquid?
What leads to the thermodynamic instability of a system when particles are dispersed into a liquid?
Which type of system is characterized by charged particles of different sizes and gravity causing hard cake formation?
Which type of system is characterized by charged particles of different sizes and gravity causing hard cake formation?
What type of forces predominate in a flocculated system?
What type of forces predominate in a flocculated system?
What is the sedimentation volume when flocculation equilibrium is achieved?
What is the sedimentation volume when flocculation equilibrium is achieved?
What is the effect of increasing the concentration of KH2PO4 on the zeta potential?
What is the effect of increasing the concentration of KH2PO4 on the zeta potential?
What is the rate of sedimentation/creaming according to the Stokes Equation?
What is the rate of sedimentation/creaming according to the Stokes Equation?
When does the rate of sedimentation/creaming become zero according to the Stokes Equation?
When does the rate of sedimentation/creaming become zero according to the Stokes Equation?
What are the limitations of the Stokes Equation?
What are the limitations of the Stokes Equation?
How can flocculation be controlled?
How can flocculation be controlled?
What is colloidal stability defined as?
What is colloidal stability defined as?
How are particles protected to prevent aggregation?
How are particles protected to prevent aggregation?
What does the zeta potential measure?
What does the zeta potential measure?
What forms when particle attraction occurs through weak and strong intermolecular forces?
What forms when particle attraction occurs through weak and strong intermolecular forces?
What prevents the formation of a hard cake on the particle?
What prevents the formation of a hard cake on the particle?
What is responsible for the energy of attraction curve describing the variation in van der Waals force with distance?
What is responsible for the energy of attraction curve describing the variation in van der Waals force with distance?
What is the role of steric in creating a repulsive barrier?
What is the role of steric in creating a repulsive barrier?
What does the Electric Double Layer consist of?
What does the Electric Double Layer consist of?
What is zeta potential dependent on?
What is zeta potential dependent on?
What is the energy condition for particles to spontaneously decrease area and lead to phase separation?
What is the energy condition for particles to spontaneously decrease area and lead to phase separation?
What is responsible for the electrical repulsion between particles being sensitive to counterions, their concentration, and valence?
What is responsible for the electrical repulsion between particles being sensitive to counterions, their concentration, and valence?
What is used to maintain electroneutrality and create a repulsive barrier?
What is used to maintain electroneutrality and create a repulsive barrier?
Study Notes
Colloidal Stability and Particle Interactions
- ΔG > 0 causes particles to spontaneously decrease area, leading to phase separation
- Particle attraction forms floccules and aggregates through weak and strong intermolecular forces
- Colloidal stability is defined as thermodynamically stable solutions and coarse dispersions being unstable
- To prevent aggregation, particles are protected by introducing repulsive interactions
- Particle-particle attraction occurs at a certain distance due to Van der Waals forces
- Energy of attraction curve describes the variation in van der Waals force with distance
- A repulsive or shielding barrier on the particle prevents the formation of a hard cake
- Repulsive barriers include steric (using long chain polymers) and electric (maintaining electroneutrality)
- Zeta potential measures the surface potential of particles and is important for system stability
- Electrical repulsion between particles is sensitive to counterions, their concentration, and valence
- The Electric Double Layer and the importance of potential-determining ions and counterions
- Zeta potential is dependent on the amount of counterion and is crucial for system stability
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Description
Test your knowledge of colloidal stability and particle interactions with this quiz. Explore concepts like ΔG, particle attraction, repulsive interactions, Van der Waals forces, zeta potential, and the Electric Double Layer. Understand how to prevent aggregation and maintain system stability in colloidal solutions.
