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PASS Content Standard 1.3
Matter has characteristic properties,
such as boiling points, melting points,
and density, which distinguish pure
substances and can be used to
separate one substance from another.
Mass
Weigh
Volume
Density
Specific Gravity
Boiling Point
Melting Point
The amount of matter
in an object.
The SI units of mass
are Kilograms.
A measure
of the pull
of gravity
on an object.
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Mass & Weight - 2 min
Gravity accelerates
all objects
downward
2
at 9.8 m/s
All objects
fall at the
same rate.
The SI units of weight
are Newtons,
2
kg m/s
The amount of space
an object
takes up.
The SI units
of volume are
Liters.
What is the
volume
of this
object?
4 cm
3 cm
5 cm
4 cm X 5 cm X 3 cm = 60
4 cm
3 cm
5 cm
3
cm
Mass per unit volume
D=
m
/V
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Density - 3 min
The density of water is
1
gram /
3
cm
A ratio of density of
a substance to the
density of water.
The density of iron
g
is 7.9 /cm3, what
is its specific gravity?
Density
of iron
:
Density
of water
=
Specific Gravity
of Iron
Think of this as DIVIDE
Density
of iron
7.9
:
g/cm3
Density
of water
:
=
Specific Gravity
of Iron
1 g/cm3
= 7.9
Density
of iron
7.9
:
g/cm3
Density
of water
:
=
Specific Gravity
of Iron
1 g/cm3
= 7.9
Since specific gravity is a ratio,
there are no units for the number.
Take in water
to dive
Release water
to surface
The temperature at which
a solid becomes a liquid.
o
Water melts at _ C
o
Table salt melts at _ C
o
Diamond melts at _ C
The temperature at which
a solid becomes a liquid.
o
Water melts at 0 C
o
Table salt melts at 801 C
o
Diamond melts at 3700 C
The temperature at which
a liquid becomes a vapor.
o
Water boils at _ C
o
Table salt boils at _ C
o
Diamond boils at _ C
The temperature at which
a liquid becomes a vapor.
o
Water boils at 100 C
o
Table salt boils at 1413 C
o
Diamond boils at 4200 C
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Melting & Vaporization - 3 min
Elements are the simplest
pure substances.
An element cannot be
changed into simpler
substances by any
chemical process.
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Fireworks - 3 min
Compounds are pure substances
made of more than one element.
Atoms of elements
in a compound are
chemically bonded
together to form
molecules.
Chemical bonds form
as the valence electrons
of atoms
interact.
Valence electrons are
those in the outer
energy level
of an atom.
Atoms form chemical
bonds to get
8 electrons in
their outer
energy level.
The tendency of an
atom to attract
electrons.
Metals generally have
a low electron
affinity.
Nonmetals generally
have a high electron
affinity.
Ionic bonds form when
electrons are transferred
from one atom
to another.
Covalent bonds form
when electrons are
shared between
atoms.
Valence electrons can
be thought of as being
the property
of all the atoms.
A way of drawing the
valence electrons
of an atom.
Ne
The chemical symbol
represents the nucleus
and all electrons
except valence
electrons
Ne
Dots indicate the
number and sub-level
location of the
valence
electrons
Ne
Begin adding dots
with the "s"sublevel
electrons...
Add the "p" sublevel
electrons one at a time,
beginning at the
top and going
counterclockwise.
Na
Mg
Al
C
N
O
F
Ne
What is the electron-dot
diagram for iron?
What is the electron-dot
diagram for silver?
What is the electron-dot
diagram for uranium?
Electron-dot diagrams
can be drawn to
represent simple
compounds.
Draw the electron-dot
diagram for hydrochloric
acid.
H
Cl
Draw the electron-dot
diagram for water.
H
H O
Polyatomic ions are
groups of covalently
bonded atoms that
have an overall charge.
Chemical formulas use
combinations of
chemical symbols to
represent compounds.
Oxidation numbers
are used to write
chemical formulas.
Oxidation numbers
indicate the number of
valence electrons an
atom will gain or lose
when forming compounds.
Elements and ions
with a positive oxidation
number will lose electrons.
Elements and ions
with a negative oxidation
number will gain electrons.
The sum of the oxidation
numbers in a compound
is always equal to zero.
You can think of a
chemical formula as
having two parts a positive part and
a negative part.
The positive part is
always written first The negative part is
always written second.
Metals are almost always
the positive part of a
formula.
Nonmetals are usually
the negative part of a
formula.
1. Write the name of the
positive element.
2. Write the name of the
negative element with
an "ide" ending.
Iron (II) chloride
Magnesium iodide
Silver nitride
Aluminum bromide
Nickel (II) sulfide
Chromium (IV) oxide
CuS
AgF
Ca3N2
Hg2C
PbO
KBr
Some compounds
contain
polyatomic ions.
A polyatomic ions is:
a group of atoms
with an overall charge.
Know these 12 polyatomic ions:
ammonium - NH4
acetate - C2H3O2
chlorate - ClO3
-1
+1
-1
Know these 12 polyatomic ions:
hydroxide - OH
nitrate - NO3
nitrite - NO2
-1
-1
-1
Know these 12 polyatomic ions:
carbonate - CO3
sulfate - SO4
sulfite - SO3
-2
-2
-2
Know these 12 polyatomic ions:
phosphate - PO4
cyanide -
-3
-1
CN
hexafluorosilicate - SiF6
-2
Formulas
with
polyatomic ions
The charge on a
polyatomic ion
is its
oxidation number
Never change a
subscript in a
polyatomic ion.
If more than one
polyatomic ion is
needed to make
the oxidation numbers
total zero....
put the polyatomic ion
in parenthesis before
adding the subscript.
When a chemical reaction
occurs, there is always a
change in properties
and energy
• Color change
• Heat change
• Gas produced
• Precipitate
formed
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Chemical Reactions - 3 min
There are five basic
types of chemical
reactions:
Two simple substances combine
to form a more complex one.
element + element
compound
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Synthesis Reactions - 3 min
A complex substance breaks
into simple substances.
compound
element + element
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Decomposition Reactions - 2 min
A single element replaces
an element in a compound.
element + compound
element + compound
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Single Displacement Reactions - 5 min
Two different elements in two
different compounds switch places.
compound + compound
compound + compound
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Double Displacement Reactions - 3 min
A hydrocarbon reacts with oxygen
to form carbon dioxide and water.
CH4 + O2
CO2 + H2O
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Combustion Reactions - 7 min
Chemical equations
represent chemical
reactions on paper.
H2 + O2
H2 O
The Law of Conservation of
Matter and Energy says that
matter can be neither created
nor destroyed during chemical
reactions.
Because of this, the products
of a chemical reaction must
contain the same atoms as
the reactants.
Reactants
Products
Correctly written chemical
equations must be balanced.
2H2 + O2
2H2O
Coefficients indicate the
number of molecules.
2H2 + O2
2H2O
Subscripts indicate the
number of atoms.
2H2 + O2
2H2O
Equations are balanced
by changing coefficients,
never by changing the
subscripts in correctly
written chemical formulas.
Seven steps are used
to balance equations
by inspection.
These steps must
be done in order.
Check for
diatomic molecules.
All diatomic molecules must
have a subscript of 2.
H 2 N 2 O 2 F2
Cl2 Br2 I2
Balance metals.
Balance nonmetals.
Balance oxygen.
Balance hydrogen.
At this point, the equation
should be balanced.
Recount all atoms.
If the numbers are not the
same, go back to step #1
and work through the steps.
Reduce coefficients,
if needed.
Do this only if every coefficient
is divisible by the same number.
S8 + O2
SO3
S8 + 12O2
8SO3
HgO
Hg + O
2HgO
2Hg + O2
Na + H2O
NaOH + H
2Na + 2H2O
2NaOH + H2
C10H16 + Cl
C + HCl
C10H16 + 8Cl2
10C + 16HCl
FeS2 + O2
Fe2O3 + SO2
4FeS2 + 11O2
2Fe2O3 + 8SO2
Two or more substances
are physically combined,
but not chemically
combined.
Homogeneous mixtures
have identical properties
throughout.
Heterogeneous mixtures
are not identical
throughout.
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Mixtures - 6 min
Special mixtures formed
when one substance
dissolves in another.
All solutions
have 2 parts
Solvent - the most abundant
substance.
Solute - the least abundant
substance.
Solutions may have several
solutes, but they will have
only one solvent.
Solution concentration
compares the amounts
of solvent and solutes.
Concentration terms like
"strong" and "dilute"
do not describe the
solution well enough for
most scientific needs.
The most common
concentration used in
chemistry is "molarity".
Molarity indicates
the number of
moles of solute
per liter of solution
One mole, in solution
One dozen equals
12
One mole equals
6.02 X 10
23
A mole of any solute is
equal to its formula mass
in grams.
How many grams of
sodium chloride are
needed to make 1 mole?
NaCl
Na = 23
Cl = 35
58 grams/mole
A liter of hydrochloric acid
solution contains 72 grams
of HCl. What is the molarity
of this acid solution?
72 g
36 g/mole
= 2M
Acids produce hydronium ions,
+
H3O in solution.
Acids produce protons
in chemical reactions.
Acids taste sour.
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Acids & Bases - 4 min
Common acids
contain hydrogen
that is ionized
in aqueous (water)
solution.
Whether an acid
is strong or weak
depends on the
amount of hydrogen
that is ionized.
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strong & weak - 3 min
Common Industrial Acids:
• Hydrochloric Acid HCl
• Nitric Acid HNO3
• Sulfuric Acid H2SO4
Bases produce hydroxide ions,
OH in solution.
Bases accept protons
in chemical reactions.
Bases taste bitter.
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Properties - 2 min
Common Industrial Bases:
• Sodium Hydroxide NaOH
• Calcium Hydroxide Ca(OH)2
• Ammonium Hydroxide NH4OH
pH is a measure of
+
H3O concentration
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pH Scale - 3 min
pH of some substances
Even "concentrated" acids and bases
are solutions containing water:
Concentrated HCl is 12 M
Concentrated H2SO4 is 18 M
Concentrated HNO3 is 16 M
Concentrated NaOH is 19 M
Use caution when diluting
acids and bases.
When Chemists take acid trips
Composed of the positive
part of a base
and the
negative part
of an acid.
Formed during a
neutralization
reaction
between an
acid and base.
HCl + NaOH
Hydrochloric
Acid
Sodium
Hydroxide
Acid + Base
NaCl + H2O
Sodium
Chloride
Water
Salt + Water
End
Content
Standard 1.3