Surfactant Activity in Chemistry

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

<p>5% (A)</p> Signup and view all the answers

<p>To select the appropriate surfactants for emulsification (C)</p> Signup and view all the answers

<p>It requires agitation for wetting (A)</p> Signup and view all the answers

<p>281 (D)</p> Signup and view all the answers

<p>It is usually a carbon chain with no affinity for water. (B)</p> Signup and view all the answers

<p>They disrupt water's structure without forming compensating bonds. (C)</p> Signup and view all the answers

<p>Surfactants will orient with hydrocarbon groups away from water. (C)</p> Signup and view all the answers

<p>It makes adsorption at the surface/interface more favorable. (A)</p> Signup and view all the answers

<p>They become stronger than water-hydrocarbon attractive forces. (A)</p> Signup and view all the answers

<p>Hydrophobic regions require structured water clusters around them. (A)</p> Signup and view all the answers

<p>Their amphipathic nature facilitates the displacement of water molecules. (C)</p> Signup and view all the answers

<p>9.13 (D)</p> Signup and view all the answers

<p>They orient with hydrophobic groups away from the aqueous phase. (D)</p> Signup and view all the answers

<p>Surface excess concentration (D)</p> Signup and view all the answers

<p>Micelles form and exist in dynamic equilibrium with monomers. (A)</p> Signup and view all the answers

<p>Surfactant molecules self-aggregate. (C)</p> Signup and view all the answers

<p>Non-ionic surfactants (C)</p> Signup and view all the answers

<p>Γ = −(Cb/RT).(dγ/dCb) (A)</p> Signup and view all the answers

<p>It exhibits a discontinuity upon reaching cmc. (D)</p> Signup and view all the answers

<p>CmC decreases and micellar size increases. (A)</p> Signup and view all the answers

<p>It increases the cmc. (D)</p> Signup and view all the answers

<p>By dividing 1 by p multiplied by Avogadro's number. (C)</p> Signup and view all the answers

<p>The majority of surfactant molecules are in the bulk phase. (D)</p> Signup and view all the answers

<p>They have a high number of counter ions bound. (A)</p> Signup and view all the answers

<p>They tend to entrap water in their structure. (D)</p> Signup and view all the answers

<p>It describes the dynamic equilibrium of surfactant concentrations. (D)</p> Signup and view all the answers

<p>It increases. (A)</p> Signup and view all the answers

<p>CH3(CH2)15(OCH2CH2)21OH (n=21) (C)</p> Signup and view all the answers

<p>It decreases the size and cmc due to reduced repulsive forces. (B)</p> Signup and view all the answers

<p>It decreases at elevated temperatures. (D)</p> Signup and view all the answers

<p>The temperature above which the solubility of ionic surfactants increases significantly. (C)</p> Signup and view all the answers

<p>Ionic micelles contain more bound counter ions, which impede movement. (C)</p> Signup and view all the answers

<p>Decreasing charge repulsion when absorbed into micelle surfaces. (D)</p> Signup and view all the answers

<p>The temperature at which aqueous solutions become cloudy. (C)</p> Signup and view all the answers

<p>It reduces viscous drag, which facilitates ion movement. (D)</p> Signup and view all the answers

A measure of the balance between hydrophilic (water-loving) and lipophilic (oil-loving) properties of a surfactant.

Surfactants with low HLB values (1-3) are more soluble in oil and tend to form water-in-oil (w/o) emulsions.

Surfactants with high HLB values (above 13) are more soluble in water and tend to form oil-in-water (o/w) emulsions.

The ability of a surfactant to create a clear solution by dispersing an insoluble substance in a liquid.

The ability of a surfactant to reduce the surface tension between two liquids, allowing them to mix more easily.

The process of creating a stable mixture of two immiscible liquids, where one liquid is dispersed throughout the other as tiny droplets.

The ability of a surfactant to prevent the formation of foam.

The specific HLB value required by an oil or fat phase to achieve a stable emulsion.

Molecules having both a hydrophilic (water-loving) and a hydrophobic (water-fearing) part. They are able to interact with both polar and non-polar environments.

The hydrophobic part of a surfactant molecule, typically a hydrocarbon chain, that dislikes and repels water.

The hydrophilic part of a surfactant molecule, that has a strong affinity for and interacts readily with water.

The tendency of non-polar substances to avoid aqueous environments, leading to increased structure and reduced entropy in water.

Surfactants accumulate at the interface between two phases (e.g., water and air), creating a barrier that lowers surface tension.

The property of surfactants to reduce the surface tension of liquids, enabling them to spread more easily and wet surfaces.

The force that acts on the surface of a liquid, creating a thin, elastic-like layer. Surfactants reduce this force, making the liquid less cohesive.

Water molecules have strong hydrogen bonds, creating a highly structured network. Adding polar or ionic solutes disrupts this structure, but the solutes can form their own hydrogen bonds with water.

The concentration of a surfactant at which micelles begin to form in solution.

The process by which surfactant molecules aggregate into spherical structures called micelles in solution.

The excess concentration of a surfactant at the surface of a liquid compared to its concentration in the bulk solution.

An equation used to calculate the surface excess concentration of a surfactant at the interface between two phases.

The tendency of molecules to move from a higher concentration area (the bulk) to a lower concentration area (the surface).

Ionic surfactants with larger counter ions exhibit lower CMC due to decreased repulsive forces between head groups.

Adding electrolytes to ionic micelles reduces repulsive forces between head groups, resulting in smaller micelles and a lower CMC.

Increasing temperature can cause non-ionic surfactants to become cloudy due to decreased solubility. This is reversible.

The temperature above which the solubility of ionic surfactants significantly increases.

Conductivity measurements can be used to determine the CMC of an ionic surfactant.

The movement of ions is hindered by the viscosity of the solvent. Micelle formation can reduce this drag, leading to increased conductivity. However, the charged micelle attracts counter ions, leading to counter-flow and reduced conductivity.

The lowest concentration of a surfactant at which micelles start to form in solution.

Self-assembled aggregates formed by surfactant molecules in solution above the critical micelle concentration (CMC) where the hydrophobic tails of the surfactant molecules are clustered together, while the hydrophilic heads point outwards interacting with the solvent.

The tendency of water molecules to form ordered structures around non-polar (hydrophobic) groups, leading to a decrease in the entropy of the system.

The tendency of surfactant molecules to self-assemble into micelles to minimize the contact between water and their hydrophobic tails.

A type of micelle with a spherical shape where the head groups (hydrophilic) are on the outer surface of the micelle interacting with the solvent and the hydrophobic tail groups are clustered inside.

The tendency of surfactant molecules to aggregate in a specific arrangement above the CMC, forming a structure that is different from the free monomer form.

The number of surfactant molecules that are associated together in a micelle.