Download Describing Matter Chapter 2:2 Physical and Chemical Properties

Describing Matter
Chapter 2:2
Terms
• Physical Properties~ a property of matter that can
be observed or measured without changing the
identity of the matter
• Physical Change~ a change that affects one or
more physical properties of a substance: many are
easy to undo
• Chemical Properties~ a property of matter that
describes a substance based on its ability to change
into a new substance with different properties
• Chemical Change~ a change that occurs when one
or more substances are changed into entirely new
substances with different properties; cannot be
reversed using physical means
• Density~ the amount of matter in a given space
Physical and Chemical
Properties
The ability to change the substance
Physical Properties
• Examples
– Color
– Odor
– Volume
– State
– Density
• Density of a substance is always the same
at a given pressure and temperature
• Density of one substance is usually
different than other substances
More Examples
• Thermal Conductivity~ the ability to
transfer thermal energy from one area
to another
• Malleability~ the ability to be pounded
into thin sheets
• Ductility~ the ability to be drawn or
pulled into a wire
• Solubility~ the ability to dissolve in
another substance
Chemical Properties
• Examples
– Flammability~ able to burn
– Reactivity with other substances
• Means something can happen
– Reactivity with oxygen (rust)
Characteristic Properties
• Always the same whether the
sample is large or small
– Density
– Solubility
– Reactivity with acids
• Used to identify and classify
substances
Physical and Chemical Change
The process of a substance
changing
Physical Change
• Does not form a new substance
• Examples
– Dissolve sugar in water
– Sanding a piece of wood
– Melting a stick of butter
• Usually easy to undo
Chemical Change
• Form new substances
• Is the actual process in which one
substance changes into another
substance
• Usually cannot be reversed by
physical means
• Example~ baking a cake
– Cake properties are different than
those of individual ingredients
Clues to Chemical Changes
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Color changes
Fizzing or foaming
Heat
Production of sound, light, or odor