Classification of Matter
Matter
Matter: Anything that has mass and volume
(takes up space)
3 phases of matter
The Nature of Matter
Gold
Mercury
Chemists are interested in the nature of matter and
how this is related to its atoms and molecules.
Chemistry & Matter
• We can explore the MACROSCOPIC
world — what we can see —
• to understand the PARTICULATE worlds
we cannot see.
• We write SYMBOLS to describe these
worlds.
A Chemist’s View of
Water
Macroscopic
H 2O
(gas, liquid, solid)
Particulate
Symbolic
A Chemist’s View
Macroscopic
Particulate
2 H2(g) + O2 (g)
--> 2 H2O(g)
Symbolic
Kinetic Nature of Matter
Matter consists of
atoms and molecules
in motion.
STATES OF MATTER
• Solids — have rigid shape, fixed volume.
External shape can reflect the atomic and
molecular arrangement.
• Liquids — have no fixed shape and may not
fill a container completely.
• Gases — expand to fill their container.
OTHER STATES OF
MATTER
• PLASMA — an electrically charged gas;
Example: the sun or any other star
• BOSE-EINSTEIN CONDENSATE
— a condensate that forms near absolute
zero that has superconductive properties;
Example: supercooled Rb gas
Physical Properties
– Characteristic of a substance that can be
observed (using your senses) without
changing the substance into something
else.
Physical properties are used to identify,
describe and classify matter.
Hardness
Texture
Color
Odor
Taste
Temperature
More EXAMPLES Physical
• size, shape, freezing point, boiling
point, melting point, magnetism,
viscosity, density, luster and many
more.
– Viscosity - The resistance of a liquid to
flowing.
– Examples:
– Low viscosity-water, rubbing alcohol
– High viscosity-honey
Physical Changes
– can be observed
without changing the
identity of the
substance
Some physical changes would
be
• boiling of a liquid
• melting of a solid
• dissolving a solid in a liquid
to give a homogeneous
mixture — a SOLUTION.
Physical Changes can be
Reversible include melting,
freezing, boiling, condensing, and
evaporating.
• Irreversible include breaking,
splitting, grinding, crushing, and
cutting.
•
Intensive/Extensive
Properties
• extensive property - a property that depends
on the amount of matter in a sample. Mass
and volume are examples of extensive
properties.
• intensive property - a property that depends
on the type of matter in a sample, not the
amount of matter.
• Every sample of a pure substance has identical
intensive properties because every sample has the
same composition. Hardness, color, conductivity,
density and malleability are examples of intensive
properties.
Chemical
Properties
• Chemical properties are characteristics
involved when a substance interacts
with another substance to change its
chemical make-up.
Flammability
Rusting
Creating a
Reactivity with
new chemical
water
product
Creating gas
bubbles
pH
Chemical Change
•Burning hydrogen (H2) in
oxygen (O2) gives H2O.
• Chemical change or
chemical reaction —
transformation of one or
more atoms or molecules
into one or more different
molecules.
Possible Signs of a Chemical
Change
• Heat- exothermic • Precipitate – a
if given off,
solid formed by
endothermic if
mixing two
taken in
liquids together
• Light
• Color Change
(sometimes)
• Gas Produced
(not from
boiling!)
A. Physical vs B. Chemical
• Examples:
– melting point
physical
– flammability
chemical
– density
physical
– magnetic
physical
– tarnishes in air
chemical
A. Physical vs B. Chemical
• Examples:
– rusting iron
chemical
– dissolving in water
physical
– burning a log
chemical
– melting ice
physical
– grinding spices
physical
Classification of Matter
• Now that we have defined chemical and
physical properties of matter, we can use that
to help us classify it.
• One way chemists classify matter is based on
its purity.
Matter
Can be
separated
physically
Pure
Substance
Mixture
Cannot
see the
parts
Can see
the parts
Heterogeneous
Mixture
suspension
Most impure
Cannot be
separated
physically
Homogeneous
Mixture
Can be
separated
chemically
Compound
Cannot be
separated
Element
colloid
Most pure
Classification of Matter
• Pure Substance – Matter that has only 1 set of
chemical and physical properties.
Example: Pure water always
has the exact same chemical
and physical properties
under the same conditions.
If water ever tastes different
then it isn’t pure water; it fits
into our next category.
Classification of Matter
• Mixture – Two or more pure substances mixed
together. Each substance in the mixture retains
its own set of chemical and physical properties.
Even though
Example:
Copper
it may
and
look
Zinc can be
different,
it mixed
is still copper
together
and
zinc. to
Each
produce
metal
brass. its own properties
retains
like melting point.
Classification of Matter
• Mixture – Two or more pure substances mixed
together. Each substance in the mixture retains
its own set of chemical and physical properties.
Unlike pure substances,
mixtures can always be
separated by physical
means.
How could we separate the
copper and zinc back out?
Mixtures
• Mixture – Two or more pure substances mixed
together. Each substance in the mixture retains
its own set of chemical and physical properties.
If a sample of sand
contains iron and salt,
how could you separate
them from the other
minerals?
Mixtures
• Some mixtures are more pure than others.
• Heterogeneous mixture – Uneven distribution
of substances. (Very impure)
- You can see the different parts.
Examples:
Sand
Granite
Wood
Mixtures
• Some mixtures are more pure than others.
• Heterogeneous mixture – Uneven distribution
of substances. (Very impure)
- You can see the different parts.
Examples:
Milk
Blood
Mixtures
• Homogeneous Mixture – Components are
evenly mixed. (More pure than heterogeneous)
- Cannot see the parts.
Salt water contains salt
and water, but are mixed
all the way to the atomic
level, but it can still be
separated by physical
means.
Seawater distillation plant
Pure Substances
• Pure substances can also be divided into 2
categories: compounds and elements.
Pure Substances
• Compound – Two or more elements chemically
bonded together.
Examples:
Carbon Dioxide (CO2)
Water (H2O)
Salt (NaCl)
Sucrose (C12H22O11)
Pure Substances
• Compounds have only 1 set of properties. They
cannot be separated by any physical process.
- Can only be separated by a chemical reaction.
Water can be
separated into
Hydrogen and Oxygen
by a process called
Electrolysis.
Pure Substances
• Elements – Substances made up of only one
type of atom.
- Cannot be separated by any physical OR
chemical process.
Examples:
Carbon
Helium
Gold
Matter
Can be
separated
physically
Pure
Substance
Mixture
Can see
the parts
Heterogeneous
Mixture
Most impure
Cannot be
separated
physically
Cannot
see the
parts
Homogeneous
Mixture
Can be
separated
chemically
Compound
Cannot be
separated
Element
Most pure
Classify the following slide using
these five classifications:
- Non-matter
- Heterogeneous Mixture
- Homogeneous Mixture
- Compound
- Element
Helium
He
Bronze
Cu + Sn
Diamond
C
Electricity
Italian Dressing
Heat
Light
Air
N2 + O2 + Ar + CO2
Mercury
Hg
Steel
Fe + C
Cookie
Iron
Fe
Carbon Dioxide
CO2
Water
H2O
Salt Water
H2O + NaCl