Chemistry – Matter Unit
• What is matter?
• What is
chemistry?
• What is the
organization of
matter?
• What is the
nature of matter?
What is NOT Matter?
Energy !
Types of Energies
• Mechanical
• Chemical
•
•
•
•
Heat
Atomic
Light
Electrical
Is Air matter?
• What are the two
criteria for
matter?
–Does it take up
space?
–Does it have
mass?
What is chemistry?
• “Chemistry is the study of the
composition, structure, and the
properties of matter and the
changes it undergoes.”
• All chemical reactions involve
energy.
What is the composition of matter?
Matter
Pure Matter
Substance
Impure Matter
Mixture
What is a pure substance?
• A pure substance has a definite
composition (proportion).
• The composition of a substance will have
the same percent of elements no matter
where the sample was obtained.
– Water from Lake Okechobee and water from
the Atlantic Ocean (once cleaned up) will
have the same composition of hydrogen to
oxygen.
– Gold is the same as other gold (once cleaned
up).
What is a pure substance?
• A pure
substance, by
definition, is an
element or a
compound.
• A container with
an almost pure
compound:
Pure Substance
Pure Substance
Element
Compound
What is an element?
• “a pure substance made of only one kind
of atom”
• A substance that cannot be decomposed
any farther by simple chemical means
• An element has a definite composition.
Gold from South Africa is the same, when
purified, as a sample from California.
Periodic Table of Elements
• Most elements on the periodic chart are metals.
• Elements through 114 but not 113 have been discovered
or made.
Elemental Samples
• Zinc, copper, lead, carbon, sulfur
What is a compound?
• “A compound is a substance
that is made from the atoms of
two or more elements that are
chemically bonded.”
• The definition is actually more
involved than this.
What is a compound?
• A compound is a substance that
cannot be decomposed any farther by
simple physical means.
• A compound has a definite
composition by mass.
• A compound is made up of two or
more elements chemically combined.
What is a compound?
• A compound no longer has the
properties of its constituent
elements.
• Table salt, NaCl or sodium
chloride, is a compound of the
element sodium and the element
chlorine.
Sodium
Sodium metal
• Soft, can be
cut with a knife
• Shiny
• Good
conductor of
electricity
• Very reactive
Sodium in water
Chlorine gas
Chlorine gas
• Greenish gas
• Poisonous
• Heavier than
air
Sodium in chlorine gas
Sodium chloride, NaCl
• Sodium chloride dissolves in water
rather than reacts with water.
• Sodium chloride is a white solid, not a
poisonous green gas.
• Sodium chloride is its own substance
with its own properties, not those of
either sodium or chlorine.
Samples of Other Compounds
• Sucrose (table sugar), Sodium Chloride,
Water, Copper(II) sulfate
Colored Compounds
• Cobalt(II) chloride, Iron(II) sulfate, Potassium
dichromate, Potassium chromate, Nickel(II)
nitrate, copper(II) sulfate
What is the composition of
matter?
Matter
Pure Substance
Impure Matter
Mixture
Impure Matter - Mixture
• “A mixture is a blend of two or
more kinds of matter, each of
which retains its own identity and
properties.”
• A mixture is made up of two or
more substances that are not
chemically combined.
Mixtures
• Mixtures can be separated by simple
physical means.
• Two mixtures containing the same
substances may not have the same
proportions.
• Example: Very salty water versus
barely salty water. Very sweet sugar
water versus slightly sweet sugar
water.
Water and Dye Mixture
• Two mixtures of the same substances may
have different proportions.
Mixtures
Mixtures
Homogeneous
Mixture
Heterogeneous
Mixture
?
Solutions
• Mixtures
– Mixture = a blend of two or more kinds of
matter, each of which retains its own
identity and properties
a) homogeneous mixture = a mixture that
is uniform in composition throughout
Ex: Food coloring and water
b) heterogeneous mixture = a mixture that
is NOT uniform in composition throughout
Ex: Oil and water
Heterogeneous Mixtures
• Sand and water on the left and sand and
gravel on the right.
Heterogeneous Mixture
Types of Mixtures:
1) solution = a homogeneous mixture
2) suspension = a mixture in which the particles are so
large that they settle out unless the mixture is constantly
stirred or agitated
Heterogeneous mixture
Ex: Sand and water
3) colloid = a mixture consisting of particles that are
intermediate in size between those in solutions and those in suspensions
Heterogeneous mixture
Ex: Milk
Colloidal Suspension
• Fog
Tyndall Effect
THE NATURE OF SOLUTIONS:
1) Solvent = the substance that does the dissolving in a solution
a) Typically present in the greatest amount
b) Typically a liquid
c) Water is the most common or “universal” solvent
2) Solute = substance being dissolved in a solution
a) Typically present in the least amount
b) Typically a solid
9 Possible Solution
Combinations:
Factors Affecting the Rate of Dissolving
(Increase Solution Rate):
• 1) Grinding: increases
surface area
• 2) Stirring: allows solvent
continual contact with solute
• 3) Heating: increases kinetic
energy; increases mixing
SOLUBILITY:
1) Solubility = quantity of solute that will dissolve in specific
amount of solvent at a certain temperature.
(pressure must also be specified for gases).
a) Ex: 204 g of sugar will dissolve in 100 g of water at 20°C
b) soluble and insoluble are relative terms
c) solubility should NOT be confused with the rate at which
a substance dissolves
2) saturated solution = a stable solution in which the
maximum amount of solute has been dissolved.
3) solution equilibrium = state where the solute is dissolving at the
same rate that the solute is coming out of solution (crystallizing).
a) Opposing processes of the dissolving and crystallizing of a solute
occur at equal rates.
b) solute + solvent
solution
4) unsaturated solution = a solution that
contains less solute than a saturated
solution under existing conditions
5) supersaturated solution = a solution that
temporarily contains more than the
saturation amount of solute than the
solvent can hold (unstable)
3 FACTORS EFFECTING SOLUBILITY:
The extent to which a given solute dissolves in a
solvent depends on the identity of the solute and
solvent and also on the existing conditions of
pressure & temperature
1) Nature of solute
and solvent
a)“Like dissolves
o
Polarity
or
like” = rule of
nonpolarity of
Solvent-Solute Combinations:
2) Pressure:
a)Pressure has little effect on the
solubility of liquids or solids in liquid
solvents.
b)The solubility of a gas in a liquid
solvent
INCREASES when pressure
increases. It is a direct relationship.
3) Temperature:
a)The solubility of a gas in a liquid
solvent DECREASES with an increase
in temperature.
b)The solubility of a solid in a liquid
solvent MOST OFTEN increases with an
increase in temperature. However,
solubility changes vary widely with
temperature changes
sometimes decreasing with temperature
increases.
Mixtures vs. Compounds
• Rocks are
mixtures.
• Minerals
are pure
substances
• Granite
rock
Mixtures vs Compounds
• Minerals are
pure substances
although many
have impuities
that must be
cleaned up first.
Minerals
Amethyst
Halite
Diamond
What is the nature of matter?
• An atom is the smallest unit of an
element that maintains the properties
of that element
– An atom is made up of electrons,
protons, and neutrons as well as other
particles.
• Protons and neutrons are made up of
quarks.
What is the nature of matter?
• A molecule is a unit
that consists of more
than one atom
bonded together.
• A molecule can have
atoms of the same
element such as
oxygen. These are
called diatomic
elements.
O2
Diatomic
Blue –elements
diatomic– blue
elementselement – red
Tetraatomic
Octatomic element - yellow
What is the nature of mature?
• A molecule can
have atoms of
more than one
type of element.
• Water
• Sugar (sucrose)
H 2O
C12 H 22 O11
Atoms and Molecules
• Three particles:
– 2 atoms of
hydrogen
– 1 atom of oxygen
• One particle:
– 1 molecule of
water
Atoms
• How can an atom of an element
be broken up into atoms of other
elements or into other smaller
particles and energy?
• Nuclear Reaction
Compound
• How is a compound broken up into its
elements or other simpler compounds?
–Use a chemical separation
method.
• What are some examples of chemical
separation methods?
Chemical Separation Methods
• Heat the compound.
Chemical Separation Methods
• Use Electrolysis
which is using an
electric current to
decompose the
compound.
• An electrolyte has
been added to the
water since water
does not conduct.
Mixtures
• How can mixtures be separated?
–Use Physical Separation
Methods.
What are examples of physical
separation methods?
Physical Separation Methods
• Distillation is the
separation of
mixtures by using
the difference in
boiling points of
liquids.
• A water cooled
condenser is used.
Physical Separation Methods
• Filtration uses
the difference in
particle size to
separate
mixtures.
• Filter papers
have different
size pores.
Physical Separation Methods
• Chromatography
uses the difference
in solubility in
various solvents.
• Gas, liquid, thin
layer, and paper
chromatography
are widely used.
States of Matter
• Three states of matter:
• Liquid, solid, gas
Physical Changes
• During physical changes matter
changes in appearance without
forming new substances.
• What some examples of physical
changes?
Physical Change Examples
• Breaking or tearing
Physical Change Examples
• Boiling or condensing
Physical Change Examples
• Freezing or melting
Physical Change Examples
• Sublimation
Physical Change Examples
• Sublimation:
• “The change of state directly to a gas
is known as sublimation.”
• “The reverse process is called
deposition, the change of state from
a gas directly to a solid.”
Chemical Changes
• During chemical changes new
substances are formed with
different properties than the
original substances.
• What is an example of a chemical
change?
Chemical Change Example
• Heating baking soda, sodium hydrogen
carbonate, forms sodium carbonate,
carbon dioxide, and water. The formation
of carbon dioxide is what causes cakes to
rise.
Mixture or Pure Substance
• These bottles contain sodium chloride,
sucrose, and a mixture of the two. Which
is which and how can they be identified?
Physical and Chemical
Properties
• What are some physical properties
of this pen?
Physical Properties
• Examples:
–Color
–Hardness
–Texture
–Volume
–Length
–Mass
Physical Properties
• More Examples:
–Density (mass/volume ratio)
–Odor
–Sound
–Boiling point
–Melting point
–Magnetism
Physical Properties
• Melting Point and freezing point
temperatures are the same.
Chemical Properties
• A chemical
property is how
something reacts.
• Does the pen float
is physical.
• Does the pen
dissolve is
physical.
• Does the pen react
with water is
chemical.
Chemical Properties
• Does the pen
burn is a
chemical
property.
• Whether and
how something
reacts is
chemical.
Extensive vs Intensive
• Extensive Properties depend upon
the amount of matter that is present.
• Intensive Properties do not depend
on the amount of matter present.
These properties are the same for a
given substance regardless of how
much of the substance is present.
Extensive vs Intensive
• Which of the properties listed
earlier are extensive and which
are intensive?
• Comparisons of several
properties are used together to
identify an unknown.
Matter Unit
Now it is time to try “Chemistry Vocabulary
Worksheet: Application of Matter”.
.
Chemistry Vocabulary
• A Symbol is a
representation of
an element.
• One or two letters
may be used.
• The first letter is
upper case while
the second is lower
case.
H C O
Fe Cl Ag
Cu Ba Cf
Chemistry Vocabulary
• A formula is a
representation of
a molecule of an
element or a
molecule of a
compound.
O2
H 2SO 4
Chemistry Vocabulary
• The subscript
represents the
12 22 11 number of
atoms of a
12 atoms of carbon
particular
22 atoms of
element in the
hydrogen
molecule.
C H O
11 atoms of oxygen
Chemistry Vocabulary
H 2SO 4
2 atoms of hydrogen
1 atom of sulfur
4 atoms of oxygen
• If no subscript
is shown. An
understood
one is
indicated.
Chemistry Vocabulary
• A coefficient is a
number in front of
a formula and
represents the
number of
molecules.
• If no coefficient is
shown, one
molecule is
indicated.
2C12 H22O11
2 molecules of sucrose
24 atoms of carbon
44 atoms of hydrogen
22 atoms of oxygen
Chemistry Vocabulary
2 H 2  O2  2 H 2O
Hydrogen oxygen water
• An equation is a sentence showing
what is happening in a chemical
reaction.
Chemistry Vocabulary
2H 2  O2  2H2O
• The reactants are the substances
(elements or compounds) that will
react. They are on the left or starting
side.
Chemistry Vocabulary
2H2  O2  2H 2O
• The products on the right side of the
equation are what are formed or are
produced during the reaction.
Chemistry Vocabulary
• An atom is the smallest unit of an
element that maintains the properties
of that element
– An atom is made up of electrons,
protons, and neutrons as well as other
particles.
• Protons and neutrons are made up of
quarks.
Chemistry Vocabulary
• A atom is made up of a nucleus and
particles outside the nucleus called
electrons.
• Electrons are negatively charged
particles.
• The mass of an electron is about
1800 times smaller than that of the
proton and neutron.
Chemistry Vocabulary
• The nucleus is the tiny positive core
of the atom.
• Two of the particles in the nucleus are
the proton and the neutron.
• The proton is a positively charged
particle.
Chemistry Vocabulary
• What is wrong with
this commonly
used picture?
• The nucleus is
1/10000 times
smaller than the
atom.
• The atom is mostly
empty space.
Chemistry Vocabulary
• Proton:
– The charge on a proton is equal in
magnitude but opposite in sign to the
charge on an electron.
• A proton is made up of three quarks.
– Two quarks have a +2/3 charge.
– One quark has a -1/3 charge.
Chemistry Vocabulary
• The mass of a proton is approximately
1800 times heavier than an electron.
• ***The number of protons present
is what determines the type of
atom.***
– If the number of protons change, an
atom of a different element is formed.
Chemistry Vocabulary
• The number of protons found in
the nucleus is known as the
atomic number.
–Hydrogen with an atomic number of
1 has only one proton. If it had 2, it
would be helium.
–Uranium with an atomic number of
92 has 92 protons.
Chemistry Vocabulary
• A neutron is an uncharged particle
found in the nucleus.
• The mass of a neutron is almost the
same as the mass of a proton.
• A neutron is made of three quarks.
– One quark has a +2/3 charge.
– Two quarks have a -1/3 charge.
Chemistry Vocabulary
• Two atoms of the same element can
have differing numbers of neutrons.
These are called isotopes.
• Hydrogen has three isotopes:
– Hydrogen with 1 proton and 0 neutrons
– Deuterium with 1 proton and 1 neutron
– Tritium with 1 proton and 2 neutrons
Chemistry Vocabulary
• The different masses of these
isotopes give them different
properties such as melting and boiling
points and reactivities and stabilities.
• Regular uranium is not radioactive
enough for a nuclear fuel. Only
certain isotopes of uranium will work.
Chemistry Vocabulary
• The mass number is the total
number of protons and neutrons in
the nucleus of the atom.
• The mass number is not found on the
periodic table.
• The masses on the table are the
weighted averages of the isotopes.
Chemistry Vocabulary
Particle
Electron
Proton
Neutron
Symbol
Charge
Mass
Number
-
1-
0

1+
1
0
0
1
e
p
n
Chemistry Vocabulary
• Nuclear Symbol:
• Mass Number
– Number of protons
and neutrons
• Atomic number
– Number of protons
– Found on Periodic
Table
235
92
U
Chemistry Vocabulary
•
•
•
•
•
•
•
Number of protons =
17
Number of neutrons =
18
Number of electrons=
17
The number of
protons = number of
electrons
35
17
Cl
Chemistry Vocabulary
25
12
Mg
•
•
•
•
•
•
Number of protons =
12
Number of neutrons =
13
Number of electrons=
12
Chemistry Vocabulary
• In a neutral atom the number of
protons is equal to the number of
electrons.
• The number of protons can never
vary in an atom.
• The electrons are the particles that
can be gained or lost in a reaction.
Chemistry Vocabulary
• The sum of the
positive protons and
the negative electrons
give the overall
charge of the atom.
• The term charge was
once called valence.
• The charge is shown
as a superscript to the
upper right.
Mg
2
Chemistry Vocabulary
•
•
•
•
•
•
•
Number of protons =
17
Number of neutrons =
19
Number of electrons=
18
(17+) + (?-) = 1– So ? = 18-
36
17
Cl
-
Chemistry Vocabulary
•
•
•
•
•
•
•
Number of protons =
12
Number of neutrons =
12
Number of electrons=
10
(12+) + (?-) = 2+
– ?- = 10
24
12
2
Mg
Chemistry Vocabulary
• An ion is a charged atom or group of
atoms.
• A cation is a positively charged ion.
• An anion is a negatively charged ion.
The prefix an- can mean not or
negative.
Chemistry Vocabulary
• Free state – The atom or molecule is
not combined with atoms of other
elements.
– Gold can be found in the free state.
– Because of its reactivity, sodium cannot.
• Combined state – The atom is part
of a compound.
Matter Unit
• Now it is time to try “Chemistry Vocabulary
Worksheet: Application of Matter”.
• The exam will cover the material in this
unit, the lab safety material, and the lab
drawer equipment.
• Know the examples and how the ideas go
together. Know all parts of the definitions.