Transcript Physical and Chemical Properties and Changes

Physical and Chemical
Properties and Changes
Physical Properties
• Any characteristic of a material that
you can observe easily without
changing the substance that makes
up the material
• You can sift out the different
substances by physical properties
• Easily observed properties
Physical Properties
• Viscosity – resistance to flow
– Low viscosity = thin liquids (runny)
– High viscosity = thick liquids (slow)
• Conductivity – heat flow
– Good conductor = heats easily (metals)
– Bad conductor = heats poorly (wood)
• Malleability – easily shaped
– Not brittle
Chemical Properties
• A characteristic of a substance
that indicates if it can undergo a
certain internal change
• These are usually internal
occurrences
• Not easily observed properties
Physical vs. Chemical
Properties
• Physical Properties • Chemical Properties
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Color
Shape
Size
Density
Amount
Volume
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Flammability
Rusting
Burning
Corrosion
Reactivity
Matter can be
changed two ways
• Physically
Physical reaction
Physical change
• Chemically
Chemical reaction
Chemical change
Physical Changes
• Most Physical changes can be reversed
• Affects one or more physical property of
a substance with out changing it’s identity
• Changes of state are physical changes
(solid liquids  gas)
Physical Changes
Do NOT CHANGE THE TYPE
OF MATTER
– Nothing new or different is formed
• Could be a change in:
Mass
Volume
Size
Density
Change in state
– Color
– Shape
Examples of
Physical Changes
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Boiling
Freezing
Dissolving
Breaking
Making a mixture 2 or more
types of matter (substances)
mixed together
– Not in specific amounts
– Can be separated physically
Chemical Changes
• A change that occurs when a
substance changes composition by
forming one or more new substances
that have different chemical and
physical properties
• Chemical changes are occurring
everywhere, including inside our body
• Chemical changes cannot be reversed
Chemical Changes
• Evidence of a chemical
reaction
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Formation of gas
Formation of precipitate
Change in color
Change in energy
• Endothermic Absorbs heat
energy (gets cold)
• Exothermic Releases heat
energy (gets hot)
Evidence: (signs of)
Physical vs. Chemical Changes
• Physical Changes • Chemical Changes
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Change of shape
Change of color
Melting point
Boiling point
Dissolving
– Changes in the
presence of light
– Flammability
– Reacting with water
– Reacting with acids
– Decomposing
– Producing a gas
– Absorbs or releases
heat