Chemical Properties
• Chemical Property
– something that leads to a change
in composition of matter
• Flammability –
– ability to burn when oxygen is
present
–Can be a good and bad property
(lighter fluid SHOULD be
flammable, Carpet is bad to be
flammable)
–Solids, liquids or gases.
• Reactivity– the ability to combine with another
substance easily
–Oxygen reacts with most
substances
• Causes rusting of metals, allows fire
to burn
• Nitrogen is not very reactive and is
often added to reduce the other
element side effects
Physical and
Chemical
Changes
How to tell the
difference
• Physical Change– physical properties change, but the
substance is the same
–Change in what you see but does
not produce a new substance
• Painting a house, cutting hair,
ironing shirt, melting
water/boiling water
Some physical changes are
reversible, some are not
• Reversible—freezing & melting
water, braiding hair
• Non-reversible—slicing a tomato,
peeling an orange
It’s a physical change if
•It changes shape
or size
•It dissolves.
It’s a physical
change if...
•It changes phase
(freezes, boils,
evaporates,
condenses)
Chemical Change
• Chemical Change– when substances react to form one
or more NEW substances
–Look for permanent change in
color, gas bubbles, leftover solid
–Non-Reversible
It’s a chemical change
if….
•It burns
• Temperature
changes without
heating/cooling
It’s a chemical change
if...
•It
bubbles
(makes a
gas)
It’s a chemical change
if...
• It changes
color
permanently
• It forms a
leftover
solid
– Examples:
• Silver ring that turns green
• Rusting cars
• Copper pennies turning green
• Baking powder in cake – cake rises
• Vinegar and baking soda
• Adding vinegar to milk
• Lighting a match
• Explosion or burning of wood
What kind of change is it
if someone...
•Tears up paper?
•Physical change
•Mixes salt and
water?
•Physical change
What kind of change is it
if someone...
•Burns paper?
•Chemical change
•Evaporates salt
water?
•Physical change
What kind of change is it
if someone...
•Mixes vinegar and
baking soda?
•Chemical change