Download CHAPTER 7 CHEMICAL FORMULAS AND CHEMICAL COMPOUNDS

CHAPTER 7
CHEMICAL FORMULAS AND
CHEMICAL COMPOUNDS
SECTION 7.1 AND 7.2
CHEMICAL NAMES AND FORMULAS
DAY1
Objectives:
¢  Explain the significance of a chemical formula.
¢  Determine the formula of an ionic compound
formed between 2 given ions.
¢  Name an ionic compound given its formula.
¢  Using prefixes, name a binary molecular
compound from its formula.
¢  Write the formula of a binary molecular
compound given its name.
OBJECTIVES CONTINUED
¢  List
the rules for assigning oxidation numbers.
¢  Give the oxidation number for each element in
the formula of a chemical compound.
¢  Name binary molecular compounds using
oxidation numbers and the Stock system.
OXIDATION NUMBERS
¢  What
is the charge on the bromide ion in NaBr?
¢  Charges are physically real; oxidation numbers
are just for bookkeeping to help keep track of
electrons.
OXIDATION NUMBERS (IN YOUR TEXTBOOK)
Ionic charge
Oxidation number
¢  Number
¢  Sign
precedes the
sign
¢  Example: 2+
precedes the
number
¢  Example: +2
OXIDATION NUMBERS
Assigning oxidation numbers:
1. 
Atoms in a pure element have an oxidation number of zero.
2. 
The more-electronegative element in a binary molecular
compound is assigned the number equal to the negative
charge it would have as an anion. The less-electronegative
atom is assigned the number equal to the positive charge it
would have as a cation.
3. 
Fluorine has an oxidation number of -1.
4. 
Oxygen has an oxidation number of -2. (except in peroxides
in which it is -1 --- H2O2 and in compounds with halogens in
which it is +2 --- OF2)
5. 
Hydrogen has an oxidation number of +1. (except in
compounds with metals in which it is-1)(CH4)
6. 
In a compound, the sum of the oxidation numbers will equal
zero.
7. 
The sum of the oxidation numbers of all atoms in a
polyatomic ion is equal to the charge of the ion.
OXIDATION NUMBERS
Assign oxidation numbers to each of the following
compounds:
a.  UF6
b.  H2SO4
c.  MgCl2
OXIDATION NUMBERS
Assign oxidation numbers to each atom in the
following compounds or ions:
a.  HCl
b.  CF4
c.  PCl3
d.  SO2
e.  HNO3
f.  KH
g.  P4O10
h.  HClO3
i.  N2O5
j.  GeCl2
SECTION 7.1
CHEMICAL NAMES AND FORMULAS
Word
¢  Formula
¢  Compound
Definition
DIFFERENTIATE THE 2 COLUMNS:
I
MgCl2
KF
SO2
N2O5
GeCl2
Al2S3
CuBr2
II
Ca(OH)2
KClO3
NH4OH
FeCrO4
NaCH3COO
Ca(NO3)2
NaMnO4
DIFFERENTIATE THE 2 COLUMNS:
I
MgCl2
Al2S3
CuBr2
NaCl
II
SO2
N2O5
CO2
NH4
HOW MANY IONS OF EACH ELEMENT ARE
PRESENT IS THE FOLLOWING COMPOUNDS?
MgCl2
2. 
KBr
3. 
Al2S3
4. 
CaI2
5. 
NaCl
What is the charge on each of the above atoms?
Total charge on a compound is ZERO.
These compounds are composed of monatomic ions.
Monatomic ions = ions formed from a single type of
atom
The above compounds are called binary ionic
compounds.
Why?
1. 
NAMING BINARY IONIC COMPOUNDS
Rules:
¢  Name the cation with the elements name.
¢  Use the root of the anion and change the ending
to –ide.
¢  Example: NaCl = sodium chloride
NAMING BINARY COMPOUNDS
1. 
2. 
3. 
4. 
5. 
MgCl2
KBr
Al2S3
CaI2
NaCl
Common anions:
Fluoride
Chloride
Bromide
Iodide
Nitride
Oxide
Sulfide
Phosphide
COMPLETE THE PRACTICE ON P. 207 #1-2.
1. 
2. 
Write formulas for the binary ionic compounds formed
between the following elements:
a. K and I
b. Mg and Cl
c. Na and S
d. Al and S
e. Al and N
Name the binary ionic compounds indicated by the
following formulas:
a. AgCl
b. ZnO
c. CaBr2
d. SrF2
e. BaO
f. CaCl2
ADDITIONAL PRACTICE:
1. 
Write the formula for the following binary ionic
compounds:
a. Mg and I
b. K and S
c. Al and Cl
d. Zn and Br
e. Cs and S
f. Sr and O
g. Ca and N
2. 
Name the following binary ionic compounds:
a. BaF2
b. CaO
c. AgF
d. CdO
e. K3N
f. NaI
g. AlBr3
STOCK SYSTEM OF NOMENCLATURE
¢ 
¢ 
¢ 
¢ 
¢ 
Some elements have 2 or more cations.
Example: Fe+2 and Fe+3
Mark these elements on your periodic table:
Cu+1 and Cu+2
Cr+2 and Cr+3
Fe+2 and Fe+3
Pb+2 and Pb+4
Sn+2 and Sn+4
V+2 , V+3, and V
Ag+1
Roman numerals are placed after the name( never in a
formula ) to indicate the charge or oxidation number
Example: copper (I) chloride = CuCl
iron (III) bromide = FeBr3
PRACTICE:
1. Write the formula and give the name for the
compounds formed between the following ions:
a. Cu+2 and Brb. Fe+2 and O-2
c. Pb+2 and Cld. Hg+2 and S-2
e. Sn+2 and Ff. Fe+3 and O-2
2. Give the names for the following compounds:
a. CuO
c. SnI4
b. CoF3
d. FeS
DAY 1
HOMEWORK:
NAME THE FOLLOWING IONIC
COMPOUNDS
1. 
2. 
3. 
4. 
5. 
6. 
7. 
8. 
9. 
10. 
MgCl2
KF
GeCl2
Al2S3
CuBr
CuBr2
FeO
Fe2O3
MgS
CaI2
11. 
12. 
13. 
14. 
15. 
16. 
17. 
18. 
19. 
20. 
K2S
CrCl2
Ag2O
CaO
Ba3P4
NaF
Na2O
BeS
MnO
BaCl2
DAY 1
HOMEWORK:
COMPOUNDS
21. 
22. 
23. 
24. 
25. 
26. 
27. 
28. 
29. 
30. 
FeBr2
CaCl2
AgBr
Na3P
AlI3
CdBr
SnO
Ba3N2
VO
NaCl
NAME THE FOLLOWING IONIC
DAY 1
HOMEWORK: WRITE THE FORMULA FOR THE
FOLLOWING.
1. 
2. 
3. 
4. 
5. 
6. 
7. 
8. 
9. 
10. 
tin (II) fluoride
potassium oxide
aluminum sulfide
silver iodide
copper (II) chloride
magnesium oxide
zinc sulfide
lead (IV) nitride
barium oxide
lithium chloride
DAY 1
HOMEWORK: WRITE THE FORMULA FOR THE
FOLLOWING.
11. 
12. 
13. 
14. 
15. 
16. 
17. 
18. 
19. 
20. 
sodium phosphide
vanadium (II) chloride
strontium (III) chloride
silver fluoride
cesium oxide
aluminum bromide
gold oxide
potassium iodide
titanium phosphide
iron (II) oxide
DAY 2
CHEMISTRY I POWER POINT PRESENTATION
Objectives:
¢  Explain the significance of a chemical formula.
¢  Determine the formula of an ionic compound.
¢  Design a presentation.
CHEMICAL COMPOUNDS POWERPOINT
PRESENTATION
¢  This
will be 2 TEST GRADES!!!!!!!
¢  1 grade for content
¢  1 grade for presentation
CHEMICAL COMPOUNDS POWERPOINT
PRESENTATION
¢  Each
student will select a metal and a non-metal
to form their compound. No two students in a
class are allowed to have the same compound.
¢  Take a few minutes to decide, then sign up your
two elements beside your name on the list on my
desk.
¢  This presentation will count as 2 TEST
GRADES!
CHEMICAL COMPOUNDS POWERPOINT
PRESENTATION
Items that you must have in your
project to receive a grade of 100 on
the content grade.
1. Chemical compound
a. Chemical formula
b. Name of chemical compound
c. Common name if applicable
d. Interesting facts
e. Usages
f. Physical description
g. State of matter
CHEMICAL COMPOUNDS POWERPOINT
PRESENTATION
2. For each element present in compound
a. Symbol
b. Number of protons, neutrons, and electrons
c. Most common charge(s)
d. Interesting facts
e. Usages
f. Most common state of matter
g. Physical description
CHEMICAL COMPOUNDS POWERPOINT
PRESENTATION
3. PowerPoint slides
a. Minimum of 4 slides
b. Minimum of 4 pictures
c. 15 lines or less per slide
d. Logical flow to slides
e. Correct grammar and spelling
f. Last slide must be work cited
LAST SLIDE
Works cited:
http://www.greensboro-nc.gov/NR/rdonlyres/
3DE716E2-060E-43E2-ACC2-D4FDEE5B6825/0/
formulas.jpg
http://www.findsounds.com/ISAPI/search.dll
www.homewood.k12.al.us/~kreaves/oxidation.JPG
CHEMICAL COMPOUNDS POWERPOINT
PRESENTATION
4. Day of presentation
a. Paper copy must be turned in with
presentation
b. Must be on time ---- NO EXCEPTIONS
c. Must be on a flash drive to present to class
and must be checked in the library before used
on my computer
CHEMICAL COMPOUNDS POWERPOINT
PRESENTATION
Items that you must have in your
project to receive a grade of 100
on the presentation grade.
These are covered on the
Presentation Rubric handout.
DIFFERENTIATE THE 2 COLUMNS:
I
MgCl2
KF
SO2
N2O5
GeCl2
Al2S3
CuBr2
II
Ca(OH)2
KClO3
NH4OH
FeCrO4
NaCH3COO
Ca(NO3)2
NaMnO4
POLYATOMIC IONS
1-
2-
3-
Acetate
Carbonate
Phosphate
Bromate
Chromate
Arsenate
Chlorate
Dichromate
Chlorite
Hydrogen phosphate
cyanide
Oxalate
Dihydrogen
phosphate
peroxide
Hydrogen carbonate
(Bicarbonate)
Sulfate
Hydrogen sulfate
Sulfite
Hydroxide
Hypochlorite
Nitrate
Nitrite
Perchlorate
Permanganate
POLYATOMIC IONS
Oxyanions = polyatomic ions that contain oxygen
¢  Sometimes oxyanions are formed by the same 2
elements.
¢  Example: NO3- and NO2- (NO3- is the most common)
¢  The most common ion is given the ending –ate.
¢  The ion with one less oxygen is given the ending
–
ite.
¢  Sometimes there are more ions.
¢  Example: ClOClO2ClO3ClO4¢  The anion with one less oxygen than the –ite ending
has the hypo- prefix. The anion with one more oxygen
than the –ate ending has the per- prefix.
¢  ClO3- is the most common.
¢  Name the anions above.
¢ 
POLYATOMIC IONS
¢  Note:
There are only 2 cations.
¢  Note: NH4+
¢  What is the name of this cation?
¢  Do not confuse this with NH3.
¢  Remember an ion has a charge.
WRITE THE FORMULA FOR TIN (IV)
SULFATE.
PRACTICE
Give the names for the following compounds:
a. Ag2O
b. Ca(OH)2
c. KClO3
d. NH4OH
e. FeCrO4
f. KClO
PRACTICE:
Write the formulas for the following ionic
compounds:
a. Sodium iodide
b. Calcium chloride
c. Potassium sulfide
d. Lithium nitrate
e. Copper (II) sulfate
f. Sodium carbonate
g. Calcium nitrate
h. Potassium perchlorate
EXTRA PRACTICE
Write the formulas for the following ionic
compounds:
a.  Copper(II) nitrate
b.  Potassium iodide
c.  Sodium hydroxide
d.  Ammonium acetate
e.  Calcium carbonate
f.  Potassium permanganate
g.  Sodium sulfate
h.  Iron(III) nitrate
EXTRA PRACTICE
Give the names of the following compounds:
a.  Ag2S
b.  NaMnO4
c.  Ba(OH)2
d.  NH4NO3
e.  Fe(ClO)2
f.  Ca(NO3)2
g.  K2SO3
h.  NaCH3COO
DIFFERENTIATE THE 2 COLUMNS:
I
MgCl2
Al2S3
CuBr2
NaCl
II
SO2
N2O5
CO2
NH3
NAMING BINARY MOLECULAR
COMPOUNDS
¢  Unlike
ionic compounds, molecular compounds
are composed of individual covalently bonded
units, or molecules!!!!!!
¢  There are 2 nomenclature systems to name
binary molecules.
¢  The older system uses prefixes.
¢  The newer system is the Stock system.
NAMING BINARY MOLECULAR
COMPOUNDS
Rules for prefix system:
1.  Less-electronegative element is given first. It is given a
prefix only if there is more than one atom.
2.  Second element is named by combining (a) a prefix
indicating the number of atoms, (b) the root of the second
element, and (c) the ending –ide.
3.  The o or a at the end of a prefix is usually dropped when
the word following the prefix begins with a vowel (example:
monoxide or pentoxide).
Unlike ionic formulas, molecular formulas are not reduced to
the simplest ratio of atoms in the compound. The actual
number of atoms is shown.
Example: benzene C6H6
NAMING BINARY MOLECULAR
COMPOUNDS
Number
Prefix
1
mono-
2
di-
3
tri-
4
tetra-
5
penta-
6
hexa-
7
hepta-
8
octa-
9
nona-
10
deca-
NAMING BINARY MOLECULAR
COMPOUNDS
Formula
N2O
NO
NO2
N2O3
N2O4
N2O5
Prefix-system name
NAMING BINARY MOLECULAR
COMPOUNDS
Give the name of As2O5.
Write the formula for oxygen difluoride.
NAMING BINARY MOLECULAR
COMPOUNDS
Name the following binary molecular compounds:
a.  SO3
b.  ICl3
c.  PBr5
Name these using the Stock system.
Write the formula for the following compounds:
a.  Carbon tetriodide
b.  Phosphorus trichloride
c.  Dinitrogen trioxide
How would these be named using the Stock
system?
NAMING BINARY MOLECULAR
COMPOUNDS
Name the following binary molecular compounds:
a.  PF5
b.  XeF4
c.  CCl4
Write formulas for the following compounds:
a.  Carbon dioxide
b.  Dinitrogen pentoxide
c.  Sulfur hexafluoride
SECTION REVIEW P. 215
2. 
a. 
b. 
c. 
d. 
e. 
f. 
g. 
h. 
Write the formulas for the compounds formed
between the following:
Aluminum and bromine
Sodium and oxygen
Magnesium and iodine
Pb2+ and O2Sn2+ and IFe3+ and S2Cu2+ and NO3NH4+ and SO42-
SECTION REVIEW
3. 
a. 
b. 
c. 
d. 
e. 
f. 
Name the following compounds using the Stock
system:
NaI
MgS
CaO
K2S
CuBr
FeCl2
SECTION REVIEW
4. 
a. 
b. 
c. 
d. 
e. 
f. 
g. 
h. 
Write formulas for each of the following
compounds:
Barium sulfide
Sodium hydroxide
Lead(II) nitrate
Potassoum permanganate
Iron(II) sulfate
Diphosphorus trioxide
Disulfur dichloride
Carbon diselenide
DAY 2
HOMEWORK: NAMING NON-BINARY
COMPOUNDS
1. 
2. 
3. 
4. 
5. 
6. 
7. 
8. 
9. 
10. 
NaNO3
Ca(OH)2
K2CO3
NH4Cl
MgSO4
AlPO4
(NH4)2SO4
Na3PO4
CuSO4
NH4OH
11. 
12. 
13. 
14. 
15. 
16. 
17. 
18. 
19. 
20. 
Li2SO3
Mg(NO3)2
Al(OH)3
(NH4)3PO4
KOH
Ca(NO3)2
K2SO4
Pb(OH)2
Na2O2
CuCO3
Day 2
Homework: formulas with polyatomic ions – complete
the table
H
Na
Mg
NH4+1
Ca
K
Al
Pb+4
OH -1
NO3-1
CO3-2
HOH
HNO3
H2CO3
SO4-2
PO4-3
DAY 2
HOMEWORK:
NAMING BINARY COVALENT
COMPOUNDS
1. 
2. 
3. 
4. 
5. 
6. 
7. 
8. 
9. 
10. 
CO
CO2
SO2
NO2
N2O
SO3
CCl4
NO
N2O5
P2O5
11. 
12. 
13. 
14. 
15. 
N2O4
CS2
OF2
PCl3
PBr5
Day 3
Section 7.3
Using Chemical Formulas
Objectives:
¢  Calculate the formula mass or molar mass of any
given compound.
¢  Use molar mass to convert between mass in
grams and amount in moles of a chemical
compound.
¢  Calculate the number of molecules, formula
units, or ions in a given molar amount of a
chemical compound.
¢  Calculate the percentage composition of a given
chemical compound.
FORMULA MASSES
¢  Formula
mass = sum of the average masses of all
atoms represented in its formula
¢  Formula mass = molecular mass
¢  Atomic masses are rounded to 2 decimal places
for all calculations in this book.
¢  Formula mass and molar mass are numerically
equal, but different in units.
¢  Formula mass = amu
¢  Molar mass = g/mol
FIND THE FORMULA MASS FOR POTASSIUM
CHLORATE.
What is the formula?
FIND THE MOLAR MASS OF EACH BELOW:
a. 
b. 
c. 
d. 
Hydrogen sulfate
Calcium nitrate
Phosphate ion
Magnesium chloride
TEST NEXT CLASS ON NOMENCLATURE
DAY 3
HOMEWORK: NAME THE FOLLOWING
1. 
2. 
3. 
4. 
5. 
6. 
7. 
8. 
9. 
10. 
BaCl2
N2O
Ag2O
CuBr
CuBr2
NH4OH
Fe2O3
PBr5
Al2O3
Al2(SO4)3
11. 
12. 
13. 
14. 
15. 
16. 
17. 
18. 
19. 
20. 
K2S
CrCl2
CrCl3
NO3
Ba3P2
Hg2I2
Na2O
CO
Pb(OH)3
Mn2O3
DAY 3
HOMEWORK:
NAME EACH AND CALCULATE THE
MOLAR MASS
Name
1. 
2. 
3. 
4. 
5. 
6. 
7. 
8. 
9. 
10. 
Na2CO3
NaOH
MgBr2
KCl
FeCl2
FeCl3
Zn(OH)2
Be2SO4
CrF2
Al2S3
Molar Mass
DAY 3
HOMEWORK:
NAME EACH AND CALCULATE THE
MOLAR MASS
Name
11. 
12. 
13. 
14. 
15. 
16. 
17. 
18. 
19. 
20. 
PbO
Li3PO4
TiI4
Co3N2
Mg3P2
Ga(NO2)3
Ag2SO3
NH4OH
Al(CN)3
Be(CH3COO)2
Molar Mass
Day 3
Homework: write the formula and calculate
the molar mass
31. 
32. 
33. 
34. 
35. 
36. 
37. 
38. 
39. 
40. 
Iron (III) oxide
Gallium nitride
Iron (II) bromide
Vanadium (V)
phosphate
Calcium oxide
Magnesium acetate
Aluminum sulfate
Copper (I) carbonate
Barium oxide
Ammonium sulfite
Formula
Molar Mass
DAY 3 STUDY FOR TEST
TEST NEXT CLASS ON NOMENCLATURE
DAY 5
WHAT IS THE MASS IN GRAMS OF 2.50 MOL OF
OXYGEN GAS?
Oxygen gas = O2
WHAT IS THE MASS IN GRAMS OF 6.25 MOL
OF COPPER (II) NITRATE?
HOW MANY MOLES OF COMPOUND ARE
THERE IN THE FOLLOWING:
a. 
6.60 g (NH4)2SO4
b. 
4.5 g Ca(OH)2
HOW MANY MOLECULES ARE THERE IN
THE FOLLOWING:
a. 
25.0 g H2SO4
b. 
125 g sugar, C12H22O11
PERCENTAGE COMPOSITION
Find the percentage composition of Cu and S in
copper (I) sulfide.
Do your results equal 100%?
PRACTICE
Find the % compositions of the following:
a.  PbCl2
b.  Ba(NO3)2
SECTION REVIEW P. 228
1. 
2. 
3. 
4. 
5. 
6. 
Determine both the formula mass and the molar
mass of ammonium carbonate.
How many moles of atoms of each element are
there in one mole of ammonium carbonate?
What is the mass in grams of 3.25 mol iron(III)
sulfate?
How many moles of molecules are there in 250 g
of hydrogen nitrate?
How many molecules of aspirin, C9H8O4 are
there in a 100.0 mg tablet of aspirin?
Calculate the % composition of each element
found in ammonium carbonate.
DETERMINE BOTH THE FORMULA MASS AND
THE MOLAR MASS OF AMMONIUM CARBONATE.
HOW MANY MOLES OF ATOMS OF EACH
ELEMENT ARE THERE IN ONE MOLE OF
AMMONIUM CARBONATE?
WHAT IS THE MASS IN GRAMS OF 3.25 MOL
IRON(III) SULFATE?
HOW MANY MOLES OF MOLECULES ARE
THERE IN 250 G OF HYDROGEN NITRATE?
HOW MANY MOLECULES OF ASPIRIN, C9H8O4
ARE THERE IN A 100.0 MG TABLET OF
ASPIRIN?
CALCULATE THE % COMPOSITION OF EACH
ELEMENT FOUND IN AMMONIUM
CARBONATE.
DAY 5
HOMEWORK:
P.
236 #32-34
DAY 6
SECTION 7.4
DETERMINING CHEMICAL FORMULAS
Objectives:
¢  Define empirical formula, and explain how the
term applies to ionic and molecular compounds.
¢  Determine an empirical formula from either a
percentage or a mass composition.
¢  Explain the relationship between the empirical
formula and the molecular formula of a given
compound.
¢  Determine a molecular formula from an
empirical formula.
SECTION 7.4
DETERMINING CHEMICAL FORMULAS
¢  Empirical
formulas = formula showing the
smallest whole-number mole ratio of atoms in the
compound
¢  Problem: Find the empirical formula of a
compound that contains 32.38% Na, 22.65% S,
and 44.99% O.
First change % to grams then calculate moles of
each. Divide each by the smallest of these
numbers. Round to the nearest whole number.
PROBLEM
Analysis of a 10.150 g sample of a compound
known to contain only P and O indicates a P
content of 4.433 g. What is the empirical formula
of this compound?
PROBLEM
Using the information form the last problem,
determine the molecular formula of this
compound if the molar mass is 283.89 g/mol.
SECTION REVIEW P. 233
1. 
2. 
3. 
4. 
5. 
A compound is found to contain 36.48% Na, 25.41%
S, and 38.11% O. Find its empirical formula.
Find the empirical formula of a compound that
contains 53.70% Fe and 46.30% S.
Analysis of a compound indicates that it contains
1.04 g K, 0.70 g Cr, 0.86 g O. Find its empirical
formula.
If 4.04 g of N combine with 11.46 g of O to produce a
compound with a formula mass of 108.0 amu, what
is the molecular formula of this compound?
The molar mass of a compound is 92 g/mol. Analysis
of a sample of the compound indicates that it
contains 0.606 g N and 1.390 g O. Find its
molecular formula.
A COMPOUND IS FOUND TO CONTAIN 36.48%
NA, 25.41% S, AND 38.11% O. FIND ITS
EMPIRICAL FORMULA.
FIND THE EMPIRICAL FORMULA OF A
COMPOUND THAT CONTAINS 53.70% FE AND
46.30% S.
ANALYSIS OF A COMPOUND INDICATES THAT IT
CONTAINS 1.04 G K, 0.70 G CR, 0.86 G O. FIND
ITS EMPIRICAL FORMULA.
IF 4.04 G OF N COMBINE WITH 11.46 G OF O TO
PRODUCE A COMPOUND WITH A FORMULA MASS
OF 108.0 AMU, WHAT IS THE MOLECULAR
FORMULA OF THIS COMPOUND?
THE MOLAR MASS OF A COMPOUND IS 92 G/
MOL. ANALYSIS OF A SAMPLE OF THE
COMPOUND INDICATES THAT IT CONTAINS 0.606
G N AND 1.390 G O. FIND ITS MOLECULAR
FORMULA.
CLASS WORK:
50
P.
236 #26, 30, 36, 37, 47,