The particles in suspensions are larger than those found in solutions. Components of a suspension can be evenly distributed by a mechanical means, like by shaking the contents, but the components will settle out.
What are the differences between solutions, suspensions, colloids, and pure substances in chemistry?
A solution is a homogenous mixture composed of two or more substances. In such a mixture, a solute is a substance dissolved in another substance, known as a solvent. A suspension is a heterogeneous mixture in which the solute particles do not dissolve. A colloid is in which one substance of microscopically dispersed insoluble particles is suspended throughout another substance. Pure substances are defined as substances that are made of only one type of atom or only one type of molecule (a group of atoms bonded together).
Resources in this Lesson
1. Discuss with students three basic types of aqueous systems: solutions, colloids and suspensions. Review aqueous systems, pure substances, and mixtures. Discuss the difference between homogeneous mixtures and heterogeneous mixtures.
Suspension vs. Colloid: How Do They Differ?
In this chapter of chemistry, we will introduce you to another form of matter, known as colloids and their solution, known as a colloidal solution. We are sure you know quite a bit about these solutions. However, we are going to dig further into the chapter, looking at their properties, types, and examples.
Imagine you are sailing on a yacht. The engine suddenly breaks down and you are stranded in the middle of the ocean. You call the Coast Guard on your radio, but cannot give them an exact location because your GPS isn’t working. Fortunately, you have a smoke flare, which you fire off. The dense colored smoke shows the Coast Guard where you are so they can rescue you. In using the flare, you are taking advantage of a type of mixture called a colloid.
Characteristics of a Colloid
A colloid may consist of particles suspended in a gas, liquid or solid, although many colloidal properties are most pronounced in liquid colloids. Gas colloids consist of particles suspended in the air or a gas medium, and include fog, smoke and atmospheric dust. Liquid colloids can consist of liquid or solid particles suspended in a liquid medium, such as milk, or incorporate gas bubbles, such as whipped cream. Solid colloids include solid foams, such as plaster, liquid-bearing solids, such as butter or cheese, and firm substances, such as paper.
Colloid chemistry at the coffee shop
Tired after your walk, you head for a coffee and doughnut. This introduces us to colloids, tiny particles of one substance (gas, liquid or solid – the disperse phase) suspended (or floating) in another (the continuous phase – gas, liquid or solid). All combinations are possible, except gas in gas, eight in all. Colloids account for a surprisingly high proportion of the substances we come across in everyday life, as a visit to a coffee shop demonstrates.
Mixtures are combinations of several substances. Each of the substances retains its physical properties. There are no new substances created. This is in contrast to a chemical reaction in which two or more reactants make new products.