Mixtures in Fluids

General Chemistry Index

Where are we going with this? The point of this deck is to give the background information and examples so that we can differentiate between substances (pure and mixtures) based on physical and chemical properties.

Mixtures in Fluids

What's a fluid?

Fluids are things that… are fluid. Not helpful? Sigh…

https://www.google.com/search?q=fluid+chemistry 
(2020-07-08)

Okay, so, mixtures in fluids are what? How about examples: milk, soda, saltwater, muddy water… You get the idea. (cf. fluids that are compounds would include water, alcohol, acetone.) There are three types of mixtures in fluids.

Mixtures can be classified as solutions, suspensions, or colloids.

Solutions:

a liquid mixture in which the minor component (the solute) is uniformly distributed within the major component (the solvent).

SOLVENT: the major component in a solution. The thing that does the dissolving…

SOLUTE: the minor component in a solution. The thing that dissolves…

Key points about solutions:

• Homogeneous
• SMALL particles of one substance within another substance.
• Liquid solutions do not separate into distinct layers.
• Cannot be filtered into different parts.
• Does not scatter light.

Colloids:

a homogeneous, noncrystalline substance consisting of large molecules or ultramicroscopic particles of one substance dispersed through a second substance. Colloids include gels, sols, and emulsions; the particles do not settle and cannot be separated out by ordinary filtering or centrifuging like those in a suspension.

gel: a semisolid colloidal suspension of a solid dispersed in a liquid.

sol: a fluid suspension of a colloidal solid in a liquid

emulsion: a fine dispersion of minute droplets of one liquid in another in which it is not soluble or miscible.

Key points about colloids:

• Homogeneous
• INTERMEDIATE sized particles of one substance within another substance.
• Liquid colloids do not separate into distinct layers.
• Cannot be filtered into different parts.
• Will scatter light—like fog or milk.

Suspensions:

a mixture in which particles are dispersed throughout the bulk of a fluid

Key points about suspensions:

• Heterogeneous
• LARGER particles of one substance within another substance.
• Liquid suspensions do separate into distinct layers.
• Can be filtered into different parts.
• Will scatter light—suspensions are cloudy.

Summary

	Pure Substance	Solution	Colloid	Suspension
Category	Homogeneous	Homogeneous	Homogeneous	Heterogeneous
Particle Size	Small	Small	Intermediate / Medium	Large
Separate Into Layers	No	No	No	Yes
Can Be Filtered	No	No	No	Yes
Scatter Light	No	No	Yes	Yes
Evaporates and Leaves a Residue	No	Yes	Yes	Yes
Examples	Water, Acetone,	Tea, Salt Water, Window Cleaner, Soda	Milk, Fog	Muddy Water, Salad Dressing