Separation Methods

Types of Solutions & Mixtures Solution: A homogeneous mixture of two or more compounds where a solute has dissolved in a solvent Homogeneous: A mixture that is perfectly uniform throughout, that is the same throughout

Mixture: A combination of two or more substances that are mixed together but not chemically combined. Mixtures can be either homogeneous or heterogeneous Heterogeneous: A mixture of substances that is not the same through out or not uniform

Examples: Homogeneous or Heterogeneous + = + = Heterogeneous

Examples: Homogeneous or Heterogeneous + + + = Heterogeneous + + + = Homogeneous

Examples Homogeneous Heterogeneous Heterogeneous

Separating Mixtures Decanting Definition: A method of separation in which a solution is poured from a container in order to leave the precipitate at the bottom of the original container When to use: When there is presence of a precipitate that is of much greater density than the solution. Ex : Solid in liquid or Oil in Water

Decanting (cont.)

Filtering Definition: A separation technique using a filter to: remove particles that are suspended in a solution physically block certain substances from passing through while allowing others to pass easily (e.g. a coffee filter) The liquid resulting after a filtration is called the filtrate

Filtering (cont.) When to Use: When a solid is present in a solution but is too fine, small or not a higher density than the liquid to allow for decanting.

Distillation Definition: A separation method that separates homogeneous mixtures by using the difference in boiling points of the different parts. As the component with the lowest density begins to boil first, the resulting gas can be collected, cooled, condensed and the separated liquid collected.

Distillation (cont.) When to Use: When a solution has little to no visible particulates (Mixture) When the presence of micro-organisms is suspected When there is a need to separate two liquids in solution

Centrifugation Definition : Relies on the same principle as decantation, only the mixture is placed in a large, fast-spinning machine called a centrifuge. The components in the mixture separate much faster this way. When to Use : Same as Decantation but much faster

Centrifugation This Photo by Unknown Author is licensed under CC BY

Sieving Definition : Involves running a mixture through a sieve that has holes of a certain size. When to Use : Separating the components of mixtures (Solids) by separating the larger particles from the smaller ones. Ex : litter

Sieving This Photo by Unknown Author is licensed under CC BY This Photo by Unknown Author is licensed under CC BY-SA

Evaporation Definition : Involves letting the liquid component of a mixture evaporate at room temperature. The solids can then be collected. When to Use : To avoid destroying the solids by heating the mixture To collect the solid components of a heterogeneous mixture

Evaporation This Photo by Unknown Author is licensed under CC BY This Photo by Unknown Author is licensed under CC BY-SA