Concept

Pure Substance

• cannot be separated into 2 or more substances by physical/mechanical means
• homogeneous, uniform composition throughout the whole sample
• properties are constant throughout whole sample
• properties do not depend on how it is prepared/purified
• has constant chemical composition

Example: Tin, Gold, Oxygen

(www.ausetute.com.au)

Mixture

• can be separated into 2 or more substances by physical or mechanical means
• displays properties of the pure substances it is made of
• composition can vary by changing proportion of pure substances making it up
• heterogeneous substances, non-uniform composition throughout sample, are always mixtures

Example: mud, cereal & milk, sand & water

(www.ausetute.com.au)

Solution

• A homogeneous mixture of one or more solutes dissolved in a solvent

Solvent: substance in which a solute dissolves to produce a homogeneous mixture

Solute: substance that dissolves in a solvent to produce a homogeneous mixture

• The solvent is the substance present in the greatest amount
• Many different kinds of solutions exist.  Solvents and solutes can be  gases, liquids or solids
• A solute cannot be separated from a solvent by filtration

Examples:  Air (oxygen dissolved in nitrogen), Water (oxygen dissolved in hydrogen), Steel (carbon and iron)

(Paul Shepson, 2010)

Refresh on Matter...

• Students should have an understanding of how matter is categorized, as seen in the chart below
• Pure substances can be an element or a compound
• A solution is categorized as a homogeneous mixture

(John Wiley & Sons, Inc, 2013)