Separating Mixtures

How can you Separate Mixtures?

• A mechanical mixture has a heterogeneous composition.

• Since the types of particles in the mixture are not strongly attracted to each other, they can be separated by a number of different ways.

Ways to Separate Mixtures

• Heterogeneous mixtures can be separated in the following ways:

– Settling or Floating– Filtration– Magnetism– By hand– Dissolving and evaporating

Settling or Floating

• Settling or Floating: When mixtures are separated into layers because of their density (meaning some float and some sink), we can separate them by skimming, pumping, or pouring off the layers.

Filtration

• Filtration: Different sized of filters are available, ranging from filters capable of capturing bacteria, to those used to sieve gravel.

Magnetism

• Magnetism: Magnets can be used to separate particles such as iron, nickel or cobalt from non-magnetic materials.

By Hand

• By Hand: Large particles that are easily identifiable can be separated by hand. For example, it would be easy to separate pieces of Trail Mix.

Dissolving and Evaporating

• Dissolving and Evaporating: Certain solvents can be used to dissolve a solute and separate it from a mixture. The solute can then be recovered by evaporating the solvent.

Separating Mixtures Questions

1. Explain which separating techniques you might use to separate the substances in each of the mixtures:– Water, sugar and sand– Water flour and marbles– Vegetable soup, salt and water– Water iron fillings and soil

Questions Continued…

2. Draw a flow chart to show hoe you would separate a mixture of iron fillings, sand, salt, stones, and sawdust.

3. Explain why settling isn’t always used to separate particles suspended in a liquid?