Upload
griselda-hardy
View
217
Download
1
Embed Size (px)
Citation preview
1. Suspensions
Suspension – a mixture containing particles that settle out if left undisturbed.
Particles are too large to be dissolved. Particles are greater than 1000 nm in diameter. They can be filtered. Examples : muddy water, many “liquid”
medicines that require “shaking,”
2. Colloids Colloid – Heterogeneous mixture of intermediate
size particles. They do not dissolve or settle. These particles remain dispersed in the
solution, they “float” and are suspended. Particles cannot be removed by filtering. They are between 1 nm and 1000 nm in
diameter. The most abundant substance in a colloid is the
dispersion medium.
If you stir an electrolyte into the colloid, it will cause the particles to settle out.
“Flocculents” bring the colloid particles together and the mass becomes so great that it forms a suspension.
Examples of colloids include smog, fog, milk, mayonnaise, marshmallow, smoke, clouds.
Colloids are classified as : sol, gels, emulsions, foam, and aerosols.
Sol – a solid dispersed in a liquidExamples : paints, blood
Gel – a solid network extending throughout a liquid.Example : gelatin (jello)
Liquid emulsion – liquid dispersed in a liquidExamples : milk, mayonnaise
Solid emulsion – liquid dispersed in a solidExamples : cheese, butter
Foam – gas dispersed in liquidExamples : shaving cream, whipped cream,
beaten egg white Solid Foam – Gas dispersed in a solid
Examples : marshmallow, soaps that float Solid aerosol – solid dispersed in gas (air)
Examples : smoke, air borne particulate matter, auto exhaust
Liquid aerosol – liquid dispersed in gas (air) Examples : fog, mist, clouds, aerosol spray
Brownian motion – the random, erratic motion of colloid particles.Caused by the polar areas of the molecules.
They attract and repel each other, keeping them in constant motion.
Tyndall Effect – particles in a colloid are large enough to scatter light.
Turbidity – how cloudy the water is.
ColloidType
Dispersed substance
Dispersing Medium Examples
Solid Sol Solid Solid Colored gems
Sol Solid Liquid Blood
Gel Solid Network Liquid Gelatin
Solid Emulsion Liquid Solid Butter, Cheese
Liquid Emulsion Liquid Liquid Milk, mayonnaise
Solid Foam Gas Solid Marshmallow, soaps that float
Foam Gas Liquid Shaving cream, whipped cream
Solid Aerosol Solid Gas Smoke, dust in air
Aerosol Liquid Gas Fog, aerosol spray, clouds