COMPOUNDS
WHAT IS A COMPOUND?
A pure substance made of 2 or more elements that are chemically combined,
forming a molecule.
If the proportion of elements is changed in a molecule, the compound changes.
Water Hydrogen Peroxide.
CO CO2
Properties of a
compound
are different than
properties of the
elements
that make it up.
Compounds do not look like or
act like the elements that form them.
Water H2O
Sucrose C12H22O11
Carbon dioxide CO2
Sodium chloride NaCl
Baking soda NaHCO3
3H2O
3 Molecules of water
6Atoms of Hydrogen
3 Atoms of Oxygen
3H2O
The 3 is the COEFFICIENT
The 2 is the SUBSCRIPT
3H2O
The COEFFICIECT tells how many molecules
The SUBSCRIPT tells how many atoms.
Coefficient
X subscript
total number of atoms
Coefficient
X subscript
total number of atoms
3H2O
Three molecules of water
6 atoms of hydrogen
3 atoms of oxygen
Coefficient
X subscript
total number of atoms
CO2
One molecule of carbon dioxide
1 atom of carbon
2 atoms of oxygen
Coefficient
X subscript
total number of atoms
8CO
8 molecules of carbon monoxide
8 atoms of carbon
8 atoms of oxygen
Coefficient
X subscript
total number of atoms
H2O2
\
1 molecule of hydrogen peroxide
2 atoms of hydrogen
2 atoms of oxygen
Coefficient
X subscript = total number of atoms
6C6H12O6
6 molecules of sugar
36 atoms of carbon
72 atoms of hydrogen
36 atoms of oxygen
144 total atoms
Writing CHEMICAL FORMULAS
A group of element symbols that shows 2 things:
the make-up of elements
the ratio of the elements in a compound
Examples
NaCl (salt)
made of 1 Sodium atom and 1 Chlorine atom
ratio of elements=1:1
CO2 (carbon dioxide)
made of 1 Carbon atom and 2 Oxygen atoms
ratio of elements = 1:2
More examples:
H2O (water) ratio of elements = 2:1
Ca(OH)2 (calcium hydroxide)
ratio of elements= 1:2:2
H2O2 (hydrogen peroxide)
ratio of elements = 2:2
CO (carbon monoxide)
Ratio of elements = 1:1
Assignment: Compound Practice
Due Friday
Women in Science Day?
Do illiterate people get the full effect of Alphabet Soup?
In chemistry, metal-nonmetal
compounds are called SALTS.
2 RULES FOR NAMING COMPOUNDS
Rule #1:
METAL-NONMETAL COMPOUNDS
Use “ide” ending
Metal is always written first
EXAMPLES:
ZnCl2 Zinc chloride
NiI2 Nickel iodide
Fe2O3 Iron oxide (rust)
MgS Magnesium sulfide
Rule #2:
NONMETAL COMPOUNDS
- use prefixes -
“Mono” = 1
“Di” = 2
“Tri” = 3
“Tetra” = 4
EXAMPLES:
CO = Carbon monoxide
CO2 = Carbon dioxide
SO3 = Sulfur trioxide
CCl4 = Carbon tetrachloride
Some Common Compounds
ACIDS
HCl - hydrochloric acid (stomach acid)
H2SO4 - sulfuric acid (battery acid)
HNO3 - nitric acid
HC2H3O2 - acetic acid (vinegar)
H2CO3 - carbonic acid (in carbonated
drinks)
BASES
NaOH - sodium hydroxide (lye)
NH4OH - ammonium hydroxide
Ca(OH)2 - calcium hydroxide
Mg(OH)2 - magnesium hydroxide (Rolaids, Milk of Magnesia)
OTHERS (SOME WE USE IN LABS)
C6H12O6 - glucose
MnO2 - manganese dioxide
CO - carbon monoxide
SO2 - sulfur dioxide
CuSO4 - copper sulfate
PbI2 - lead iodide
KI - potassium iodide
Fe2O3 - iron oxide (rust)
BaCl2 - barium chloride
NaNO3 - sodium nitrate
ZnCl2 - zinc chloride
N2O - nitrous oxide (laughing gas)
Let's start with using your flash cards..............
HCl
NaOH
H2O2
C6H12O6
H2SO4
NaHCO3
HC2H3O2
NaNO3
Ca(OH)2
NH3
H2CO3
MnO2
CuSO4
Mg(OH)2
CaCO3
Fe2O3
CaO
ZnCl2
NaOH
SiO2
NH4OH
N2O
PbI2
C2H5OH
Dot Diagrams Practice
Beryllium
Silicon
Chlorine
Neon
Magnesium
Argon
Sulfur
Calcium
Lewis Dot Diagrams of the First Three Periods
Lithium
Sodium
Potassium
Let's start with using your flash cards..............
Write the compound in your notebook, write the name of the compound next to it.
See how many you know!
BaCl2
C6H12O6
CuSO4
HNO3
C2H5OH
C12 H22 O11
SiO2
Fe2O3
Ca(OH)2
HCl
NH3
CaO
H2O2
Mg(OH)2
BaCl2 Barium Chloride
C6H12O6 Glucose
HNO3 Nitric Acid
CuSO4 Copper Sulfate
C12 H22 O11 Sucrose
C2H5OH Ethanol
Fe2O3 Iron Oxide
NH3 Ammonia Gas
SiO2 Silicon dioxide
Ca(OH)2 Calcium Hydroxide
CaO Calcium Oxide
HCl Hydrochloric acid
H2O2 Hydrogen peroxide
Mg(OH)2 Magnesium hydroxide
Molecules
A molecule contains two or more atoms
bonded together into one particle.
Oxygen atom
Hydrogen atom
Oxygen molecule (O2 )
Water molecule (H2O)
Does one atom make a difference in a molecule?
CO CO2
Objective: The smallest part of a compound that still has the properties of that compound is
called a molecule. Molecules are groups of atoms that are chemically bonded together due
to the interactions of their electrons. Today, we are going to construct some basic
molecules to strengthen our understanding of why certain atoms prefer to bond with each
other.
Procedure: Our task today is to construct 15 molecule models. Then, we are going to draw,
label and color these models on the back of this sheet. Use the information in the table
below when creating your models so that we have consistency throughout the classroom.
Provide a key for your drawings.
ELEMENT
COLOR
No. of BONDS
Hydrogen
Yellow
1
Sodium
Purple
1
Chlorine
Green
1
Oxygen
Red
2
Nitrogen
Blue
3
Carbon
Black
4
CH4
2 CH4
C2H6
H2
4 H2
H2O
2H2O
NaCl
2HCl
NaOH
2 H2O2
NH3
CCl2H2
NaNH2
N2 + 2 H2 + 2 O2
Water Molecule
H2O
Two atoms of hydrogen
One atom of oxygen
Fire needs oxygen so in this demo, you can see the candle burning normally in air in
the presence of oxygen.
The combustion reaction is:
wax + oxygen in the air ---> carbon dioxide + water
C22H44 + 33 O2 ---> 22 CO2 + 22 H2O + heat energy
When the baking soda and vinegar combine, they form carbon dioxide gas. Carbon
dioxide is more dense than air, so therefore it fills the bottom of the beaker first.
The carbon dioxide slowly rises to the top of the beaker, forcing the air with oxygen out
of the beaker. Since there is a lack of oxygen, the flame is extinguished.
vinegar + baking soda ---> sodium acetate + carbon dioxide gas +water acetic acid +
sodium bicarbonate
HC2H3O2 + NaHCO3---> NaC2H3O2 + CO2 + H2O