Transcript Chemical properties

CHEMICAL PROPERTIES
Chapter 8 - 3
IDENTIFYING CHEMICAL
PROPERTIES
• Chemical properties are the
ability of substances to change
into entirely new substances.
• The new substances have a
different set of properties from
the original substances.
REACTIVITY &
NONREACTIVITY
• Reactivity is the ability of a substance
to change into one or more substances.
• Flammability, a type of reactivity, is the
ability to burn.
• Wood burns = Flammable
• Smoke & ash don’t =
nonflammable
• Rusting is reactivity
of iron to oxygen.
COMPARING PROPERTIES
• If the property is physical, you can
observe that property without changing
the identity.
• Chemical properties are not easy to see
until the change is taking place, like when
wood is burning.
CHARACTERISTIC PROPERTIES
• Characteristics that are the most
useful in identifying substances are
called characteristic properties.
• Density and reactivity are two of
these properties.
• Scientists rely on these to identify
and classify substances.
CHEMICAL CHANGES & NEW
SUBSTANCES
• A chemical change happens when a
substance changes into something new.
• You can usually see a chemical change.
SIGNS OF CHEMICAL
CHANGES:
• Chemical changes often cause color
changes, fizzing or foaming, a
temperature change, production of
sound, light, or odor.
• Chemical changes cannot be “undone”
because the substance’s identity
changes.
EXAMPLES OF CHEMICAL
CHANGES:
• Soured milk smells bad because
bacteria have formed new substances in
the milk.
• Statue of Liberty turned green because
the copper reacts to the moist air.
• Effervescent tablets bubble because
the ingredients react with water.
• Hot gases from a rocket form because
hydrogen and oxygen join to make
water.
THE END
• CHAPTER 3 - 3