Transcript States of Matter - Barrington Public Schools

Matter: Properties &
Change
Chapter 3
Matter
• Matter – anything that has mass and
takes up space
– Everything around us
• Chemistry – the study of matter and the
changes it undergoes
Four States of Matter
• Solids
– particles vibrate but can’t move
around
– fixed shape
– fixed volume
– incompressible
Four States of Matter
• Liquids
– particles can move around
but are still close
together
– variable shape (shape of
container)
– fixed volume
– virtually incompressible
Four States of Matter
• Gases
– particles can separate and move
throughout container
– variable shape
– variable volume
– easily compressed
– vapor = gaseous state of a
substance that is a liquid or
solid at room temperature
Four States of Matter
• Plasma
– particles collide with enough energy to
break into charged particles (+/-)
– gas-like, variable
shape & volume
– stars, fluorescent
light bulbs
Physical Properties
• Physical Property
can be observed without changing the
identity of the substance
Physical Properties
• Physical properties can be described as
one of 2 types:
• Extensive Property
depends on the amount of matter present
(example: length)
• Intensive Property
depends on the identity of substance, not
the amount (example: density)
Chemical Properties
• Chemical Property
describes the ability of a substance to
undergo changes in identity
Physical vs. Chemical Properties
• Examples:
– melting point
physical
– flammable
chemical
– density
physical
– magnetic
physical
– tarnishes in air
chemical
Physical Changes
• Physical Change
– changes the form of a substance without
changing its identity
– properties remain the same
• Examples: cutting a sheet of paper,
all phase changes
Phase Changes
Evaporation =
Liquid  Gas
Condensation =
Gas  Liquid
Melting =
Solid  Liquid
Freezing =
Liquid  Solid
Sublimation =
Deposition =
Solid  Gas
Gas  Solid
Chemical Changes
• Process that involves one or more
substances changing into a new
substance
– Commonly referred to as a chemical
reaction
– New substances have different
compositions and properties than the
original substances
Chemical Changes
• Signs of a Chemical Change
– change in color or odor
– formation of a gas
– formation of a precipitate (solid)
– change in temperature
Physical vs. Chemical Changes
• Examples:
– rusting iron
chemical
– dissolving in water
physical
– burning a log
chemical
– melting ice
physical
– grinding spices
physical
Law of Conservation of Mass
• Although chemical changes occur,
mass is neither created nor destroyed
in a chemical reaction
• Mass of reactants equals mass of
products
massreactants = massproducts
A + B C
Conservation of Mass
• In an experiment, 10.00 g of red mercury (II) oxide
powder is placed in an open flask and heated until it is
converted to liquid mercury and oxygen gas. The liquid
mercury has a mass of 9.26 g. What is the mass of
the oxygen formed in the reaction?
GIVEN:
WORK:
10.00 g = 9.86 g + moxygen
Mercury (II) oxide 
mercury + oxygen
Mercury
(II) oxide 
mercury
+ oxygen
mmercury(II)
oxide = 10.00 g
moxygen
= (10.00
g – 9.86
mmercury
= 9.86 g
Mmercury(II)
oxide = 10.00 g
moxygen
=?
Mmercury
= 9.26 moxygen = 0.74 g
Moxygen = ?
massreactants = massproducts
g)
Matter Flowchart
MATTER
yes
Can it be physically
separated?
MIXTURE
yes
Is the composition
uniform?
Homogeneous
Mixture
(solution)
no
PURE SUBSTANCE
no
Heterogeneous
Mixture
yes
Can it be chemically
decomposed?
Compound
Element
no
Matter Flowchart
• Examples:
– graphite
element
– pepper
heterogeneous mixture
– sugar (sucrose)
compound
– paint
heterogeneous mixture
– soda
solution
Pure Substances
• Element
– composed of identical atoms
– Example: copper wire, aluminum foil
Pure Substances
• Compound
– composed of 2 or more
elements in a fixed ratio
– properties differ from those
of individual elements
– Example: table salt (NaCl)
Mixtures
• Variable combination of 2 or more pure
substances.
Heterogeneous
Homogeneous
Mixtures
• Solution
– homogeneous
– very small particles
– particles don’t settle
– Example: rubbing alcohol
Mixtures
• Heterogeneous
– medium-sized to
large-sized
particles
– particles may or
may not settle
– Example: milk,
fresh-squeezed
lemonade
Mixtures
• Examples:
• Answers:
– tea
– Solution
– muddy water
– Heterogeneous
– fog
– Heterogeneous
– NaCl & H2O
– Solution
– Italian salad dressing
– Heterogeneous
Separating Mixtures
• Substances in a mixture are
physically combined, so processes
bases on differences in physical
properties are used to separate
components
• Numerous techniques have been
developed to separate mixtures to
study components
–
–
–
–
–
Filtration
Distillation
Sublimation
Crystallization
Chromatography
Filtration
• Used to separate
heterogeneous mixtures
composed of solids and
liquids
• Uses a porous barrier to
separate the solid from
the liquid
• Liquid passes through
leaving the solid in the
filter paper
Distillation
• Used to
separate
homogeneous
mixtures
• Based on
differences in
boiling points of
substances
involved
Sublimation
• Process during which a solid changes
to a vapor without melting
• Can be used to separate two solids
present in a mixture when one of the
solids sublimates but the other does
not
Crystallization
• Separation technique
that results in the
formation of pure solid
particles from a
solution containing the
dissolved substance
• As one substance
evaporates, the
dissolved substance
comes out of solution
and collects as crystals
• Produces highly pure
solids
• Rocky candy is an
example of this
Chromatography
• Separates components of a
mixture based on ability of each
component to be drawn across the
surface of another material
• Mixture is usually liquid and is
usually drawn across
chromatography paper
• Separation occurs because various
components travel at different
rates
• Components with strongest
attraction for paper travel the
slowest; components with strongest
attraction for the liquid travel the
fastest
Separation of a Compound
The Electrolysis of Water
Compounds must be
separated by
chemical means.
With the application
of electricity, water
can be separated
into its elements
Reactant

Water

2 H2O

Products
Hydrogen + Oxygen
2 H2
+
O2