Colloidal Chemistry Basics

A mixture where particles are evenly distributed but too small to be seen with the naked eye, appearing homogeneous but are actually heterogeneous.

The scattering of light by particles in a colloidal dispersion, making the beam visible. This distinguishes colloids from true solutions.

A type of filtration that uses a membrane to separate larger particles from a solution

The ability of a substance to absorb light, blocking it from passing through.

The size of individual particles in a mixture affects how easily they are absorbed by the body.

The tendency of particles, surfaces, or functional groups to become extensively wetted, solvated, swollen, or dissolved by solvents.

Materials that do not disperse spontaneously in a liquid. Special methods must be used to create a colloidal dispersion.

Lyophobic sols with a strong attraction between particles coagulate easily, forming distinct granules. The system can't be easily restored to its original state.

At high concentrations, lyophobic systems can transition into pastes due to strong inter-particle attraction.

Colloidal aggregates form spontaneously when amphiphilic molecules exceed a certain concentration called the 'critical micelle concentration'.

Lyophilic molecules disperse spontaneously in a liquid to form a colloidal solution. These are generally easy to prepare.

Lyophobic colloids can't be prepared by simply mixing with the disperse medium. They require special methods like using SAA (stabilizers) or mechanical reduction.

Lyophilic colloids can be created by directly mixing with the disperse medium. They are relatively easy to prepare.

The stability of lyophobic colloids is maintained mainly by electrostatic repulsion between charged particles. This repulsion prevents particles from aggregating due to the attraction of their surface forces.

The stability of lyophilic colloids is maintained by a combination of charge and solvation. The particles are surrounded by a layer of solvent molecules, creating a 'solvation shell' that effectively prevents them from aggregating.

The process of forming a colloidal dispersion where particles are distributed throughout a solvent.

• Lyophobic colloids require special methods like grinding or applying energy to overcome repulsive forces.
• Lyophilic colloids form spontaneously due to their strong attraction to the solvent.

The movement of colloidal particles in a random, zigzag path due to collisions with molecules of the dispersion medium. This movement contributes to the diffusion of colloidal particles.

The scattering of light by particles in a colloidal dispersion is inversely proportional to the fourth power of the wavelength of light. This explains why shorter wavelengths, like blue, scatter more strongly than longer wavelengths like red.

When large polymer molecules cover the surface of lyophobic particles, they can create a protective layer that prevents coagulation, even in the absence of a significant zeta potential.

The ability of colloidal particles to settle under the influence of gravity or a centrifugal force. This is influenced by factors like particle size and density.

The tendency of dissolved substances to move from a region of high concentration to a region of low concentration. In colloids, the osmotic pressure is low due to the large size of the dispersed particles.

The use of a strong centrifugal force to separate colloidal particles based on their size and density. It is a more effective method than sedimentation.

The movement of charged colloidal particles towards the oppositely charged electrode in an electric field.

The tendency of a gel to absorb liquid and increase in volume.

The property of a colloid that resists flow and deformation, resulting in a thicker consistency.

The pressure required to prevent the movement of solvent across a semipermeable membrane into a solution with a higher concentration of solute.

A type of colloidal dispersion where the dispersed phase doesn't have a strong affinity for the dispersion medium. They need special preparation methods like mechanical reduction or adding stabilizers.

When dispersed particles in a lyophobic sol come together and clump, forming a visible, distinct separation between the phases. The original state is hard to recover.

Layered particles that form a gel-like structure. The faces are negatively charged, and edges are positively charged, leading to electrostatic attraction.

The shape of colloidal particles in a dispersion influences their surface area and interactions. Extended shapes have more surface area and are prone to attractive forces.

These colloids have high molecular weights and form random coils in solutions. Their extended structure enhances their interactions with the dispersing medium.

The ability of a material to change its viscosity based on applied force. After being sheared, it regains its viscosity over time.

Weak attractions between particles in a lyophobic gel that can affect the gel's viscosity and flow properties.