This quiz covers laboratory techniques used in chemistry, including dialysis and ultrafiltration, to separate particles and molecules based on their size and properties.

Created by

@CompactCombination

Questions and Answers

What is the principle of dialysis?

Separation of micromolecular impurities based on diffusibility

What is the purpose of stirring in dialysis?

To maintain a high concentration gradient across the membrane

What is the main difference between dialysis and ultrafiltration?

Dialysis separates based on diffusibility while ultrafiltration separates based on size

What is the purpose of the electric potential in electrodialysis?

<p>To accelerate the movement of ionic impurities through the dialyzing membrane</p> Signup and view all the answers

What is the effect of electrical repulsion and particle adsorption on ultrafiltration?

<p>They decrease the correlation between particle and pore sizes</p> Signup and view all the answers

Study Notes

Dialysis

Colloidal particles are too large to pass through membranes like collodion or cellophane, but smaller molecules can.
Dialysis separates micromolecular impurities from colloidal dispersions based on diffusibility.
Stirring is necessary to maintain a high concentration gradient across the membrane, which hastens the process.

Ultrafiltration

Uses pressure or suction to force solvent and small particles across a membrane while retaining larger colloidal particles.
Membrane filters with known pore sizes can determine colloid particle sizes.
Membrane permeability is influenced by factors like electrical repulsion and particle adsorption, affecting the correlation between particle and pore sizes.

Electrodialysis

Applies an electric potential to accelerate the movement of ionic impurities through a dialyzing membrane.
Enhances purification speed, termed electrodecantation, by concentrating charged colloidal particles on one side of the membrane.