Physical Properties
• Any characteristic of a material that you can observe without changing the makeup of the material
Examples:ColorShapeSizeDensityMelting PointBoiling Point
Appearance
• Appearance is the most obvious physical property
• Shape, color, and state of matter can be identified just by looking
• They can also be measured
• Volume
• Temperature
• Mass
• Diameter
Behavior
• Behavior is also a physical property
• Examples:
• Magnetism
• Malleable
• Ductile
• Ability to flow
Using Physical Properties to Separate
• Some items can be separated by physical properties
• Sorting by hand
• Sifting
• Using a magnet
Physical Properties
• Can be used to identify substances
• Many physical properties are specific to the material and remain constant and can be used for identification
• Melting point
• Boiling point
• Density
• Specific Heat
Physical Changes
• Any change that does alter the makeup of the material
• You can change size, shape, or state of matter without altering the makeup of the material
• Sometimes physical change can accompany a color change without changing the composition of the material
• Heating a metal until it’s glowing hot
• Sometimes color change accompanies a chemical change
• Rusting
Using Physical Change to Separate
• We can also use physical change to separate materials
• Distillation is a separation technique that allows separation techniques by boiling point
• A mixture is heated until it boils.
• All the material that evaporates at a specific boiling point and be captured when it condenses
• The material that did not boil at that boiling point is left behind
Chemical Properties
• Chemical properties are characteristics of a substance that indicate whether it is likely to undergo a chemical change
• Flammability
• Reactive to light
• Reactivity
• Toxicity
Chemical Change
• The change of one substance into another
• There are several clues that a chemical change is going on
• Rapid release of energy
• Change of heat
• Light
• Sound
• Bubbling
• Color change
• Formation of a solid (precipitate)
Using Chemical Change to Separate
• Silver flatware can become tarnished
• Due to silver reacting with sulfur in the air to make silver sulfide
• The reaction can be reversed by putting the silver in warm water with baking soda and aluminum foil
• In industry and labs, chemical changes like this are used to purify metals
The Conservation of Mass
• During any chemical change, mass is conserved.
• The amount of substance present at the beginning of the reaction will be equal to the amount of substance present at the end of reaction
• Then why does there appear to be less mass after a log burns
• Mass is “lost” as water and gas