Ch 7 Sec 1 Chemical Names

1
Modern ChemistryChapter 7Chemical Formulas and
Chemical Compounds
Sections 1, 3 4 Chemical Names and Formulas
Using Chemical Formulas Determining Chemical
Formulas
Ch 7 Sec 1 Chemical Names Formulas pages
219-231
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2
Monatomic ion Binary compound Nomenclature
Oxyanion Hydrocarbon Salt
Chapter Vocabulary
Ch 7 Sec 1 Chemical Names Formulas pages
219-231
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3
Section 1
Chemical Namesand Formulas
Ch 7 Sec 1 Chemical Names Formulas pages
219-231
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Chemical Formula
Molecular compounds for one
molecule Ionic compounds for one formula unit
the simplest ratio of cations to anions
C
H
8
18
4
5
Chemical Formula
5 ions two Al 3 ions and three
(SO4) 2- ions
Al
(SO )
2
4
3
5
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Definitions

• Hydrocarbon compounds containing hydrogen and
  carbon
• Binary Compound compound with only two types of
  atoms
• Nomenclature a naming system
• Oxyanions negative polyatomic ions with oxygen
  in them

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Definitions

• Monatomic ions ions formed from a single atom
• For negative monatomic ions, -ide is added to the
  root name

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How can I tell if the compound is ionic or
covalent ????
Ionic compounds contain a metal and/or a
polyatomic ion !!!
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Writing Fomulas and Naming
Ionic Compounds
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Charges on Monatomic Ions
1
2
3
3-
2-
1-
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Charges on Transition Metals
Ag 1 Zn 2 Cu 1 or 2 Fe/Cr 2 or 3
Sn 2 or 4 Pb 2 or 4
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Charges of Metals
PbO2 and PbO
Ch 7 Sec 1 Chemical Names Formulas pages
219-231
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Polyatomic Ions Page 226
Ch 7 Sec 1 Chemical Names Formulas pages
219-231
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Ionic Compounds

• Formulas
• Write the symbols
• Determine the charges
• Monatomic ions from the periodic table
• Transition metals from a roman numeral
• Polyatomic ions from a chart on p. 226
• Cross the charges.
• Reduce to lowest ratio.

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Ionic Compounds

• Names
• Write the cation name.
• Write the anion name.
• Add ide to the anion if monatomic
• Add the roman numeral for any transition or group
  14 metal.
• NO PREFIXES!!!!

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Ionic Binary Compounds
Aluminum Oxide
FORMULAS
3
2-
Al
O
3
2
(3 x ) (2- x ) 0
2
3
Al2O3
(charge x subscript)(charge x subscript) 0
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Ionic Binary Compounds
Aluminum Oxide
FORMULAS
3
2-
Al
O
3
2
REDUCE IF NECESSARY!!
Al2O3
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Ionic BinaryCompounds
NAMING
Mg3N2
NO PREFIXES!!
Nitrogen
ide
Magnesium
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1. Write formulas for the binary ionic compounds
formed between the following elements a.
potassium and iodine b. magnesium and chlorine
c. sodium and sulfur d. aluminum and sulfur
e. aluminum and nitrogen 2. Name the binary
ionic compounds indicated by the following
formulas a. AgCl e. BaO b. ZnO
f. CaCl2 c. CaBr2 d. SrF2
Practice Page 223
Ch 7 Sec 1 Chemical Names Formulas pages
219-231
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Ionic Compounds with Transition Metals
FORMULAS
Iron (III) Chloride
3
1-
Fe
Cl
3
1
(3 x ) (1- x ) 0
1
3
FeCl3
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Ionic Compounds with Transition Metals
FORMULAS
Tin (II) Oxide
2
2-
Sn
O
1
1
(2 x ) (2- x ) 0
1
1
SnO
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Ionic Compounds with Transition Metals
FORMULAS
Tin (II) Oxide
2
2-
Sn
O
1
2
1
2
REDUCE!
SnO
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1. Write the formula and give the name for the
compounds formed between the following ions a.
Cu 2 and Br - d. Hg 2 and S 2- b. Fe 2
and O 2- e. Sn 2 and F - c. Pb 2 and Cl
- f. Fe 3 and O 2- 2. Give the names for
the following compounds a. CuO c. SnI4
b. CoF3 d. FeS
Practice Page 225
Ch 7 Sec 1 Chemical Names Formulas pages
219-231
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Ionic Compounds with Transition Metals
NAMING
PbO
( x 1 ) ( 2- x 1 ) 0
2
NO PREFIXES!!
Lead
Oxygen
ide
II
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Ionic Compounds with Polyatomic Ions
FORMULAS
Ammonium Sulfate

2-
(NH )
(SO )
4
2
4
1
(1 x ) (2- x ) 0
2
1
(NH4)2SO4
Parenthesis are needed if the p. ion has a
subscript.
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Ionic Compounds with Polyatomic Ions
NAMING
Ca(NO3)2
NO PREFIXES!!
Nitrate
Calcium
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1. Write formulas for the following ionic
compounds a. sodium iodide e.
copper(II) sulfate b. calcium chloride
f. sodium carbonate c. potassium sulfide
g. calcium nitrite d. lithium nitrate h.
potassium perchlorate 2. Give the names for the
following compounds a. Ag2O b. Ca(OH)2 c.
KClO3 d.NH4OH e. Fe2(CrO4)3 f. KClO
Practice Page 227
Ch 7 Sec 1 Chemical Names Formulas pages
219-231
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Writing Fomulas and Naming
Molecular Compounds
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Prefixes for Covalent
Ch 7 Sec 1 Chemical Names Formulas pages
219-231
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p. 228
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Molecular Compound

• Formulas
• Write the symbols.
• Use prefixes for subscripts.
• DONT reduce.

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Molecular Compound

• Names
• Write the name of the elements.
• Order Smaller group number first
• Same group? Greater period number first.
• Add ide to the second element.
• Add prefixes to each element for the number of
  atoms.

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Binary Molecular Compounds
FORMULAS
Disulfur difluoride
S
F
2
2
DON'T REDUCE!
S2F2
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Binary Molecular Compounds
NAMING
O
N
2
4
nitrogen
oxygen
ide
di
tetra
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Binary Molecular Compounds
NAMING
O
H
2
hydrogen
oxygen
ide
di
mon
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Binary Molecular Compounds
NAMING
O
H
2
2
hydrogen
oxygen
ide
di
di
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1. Name the following binary molecular compounds
a. SO3 b. ICl3 c. PBr5 2. Write formulas for
the following compounds a. carbon tetraiodide
b. phosphorus trichloride c. dinitrogen trioxide
Practice Page 229
Ch 7 Sec 1 Chemical Names Formulas pages
219-231
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Acids and Salts

• Acids Chapter 14
• Binary Acids two elements hydrogen and one
  other element
• Oxyacids contain hydrogen, one other element
  and oxygen
• Acid a solution of the compound in water.

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Acids and Salts

• Salt an ionic compound
• Made from
• the cation of a base and
• the anion of an acid
• Some retain an H in the anion
• Example CO3 carbonate
• HCO3 1- hydrogen carbonate or
  bicarbonate

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List of Acids
Ch 7 Sec 1 Chemical Names Formulas pages
219-231
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p. 230
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Section 1 Homework
Section Review Page 231 1-5
Ch 7 Sec 1 Chemical Names Formulas pages
219-231
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Modern ChemistryChapter 7Chemical Formulas and
Chemical Compounds

• Sections 1, 3 4
• Chemical Names and Formulas
• Using Chemical Formulas
• Determining Chemical Formulas

Ch 7 Sec 3 Using Chemical Formulas pages 237-244
41
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Monatomic ion Binary compound Nomenclature
Oxyanion Salt Formula Mass Percent
Composition Empirical Formula
Chapter Vocabulary
Ch 7 Sec 3 Using Chemical Formulas pages 237-244
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Section 3
Using Chemical Formulas
Ch 7 Sec 3 Using Chemical Formulas pages 237-244
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Definitions

• Formula Mass
• the mass of any molecule, formula unit or ion.
• The sum of all the average atomic masses of all
  the atoms represented by the formula
• Unit a.m.u.
• Molecular mass
• Mass of a molecule in a.m.u.

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Definitions

• Molar mass
• the mass of one mole of atoms of an element
• The mass of one mole of molecules or formula
  units of a compound
• Numerically equal to formula mass
• Unit grams/mole (g/mol)

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Calculating Formula Mass or Molar Mass

• List the elements in the compound.
• List the number of atoms of each element.
• Multiply each number of atoms by the
• Relative atomic mass (for formula mass)
• Molar mass (for molar mass)
• Add the products.

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Calculating Formula Mass or Molar Mass

• List the elements in the compound.
• List the number of atoms of each element.
• Multiply each number of atoms by the
• Relative atomic mass (for formula mass)
• Molar mass (for molar mass)
• Add the products.

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Calculating Formula Mass or Molar Mass
(NH4)2SO4
The unit is amu for formula mass. The unit is
g/mol for molar mass
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1. Find the formula mass of each of the
following a. H2SO4 b. Ca(NO3)2 c. PO4 3- d.
MgCl2
Practice Page 238
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2. Find the formula mass of each of the
following a. Al2S3 b. NaNO3 c. Ba(OH)2
Practice Page 239
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One mole of
Nitrogen (balloon) CdS (yellow) Water
(cylinder) NaCl (white)
Ch 7 Sec 3 Using Chemical Formulas pages 237-244
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p. 239
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Chemical Formulas Moles
H
O
2

• The formula could stand for 1 molecule of water
  with 2 hydrogen atoms and 1 oxygen atom or
• The formula could stand for 1 mole of water
  molecule which contain 2 moles of hydrogen atoms
  and 1 mole of oxygen atoms.

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Conversions with Compounds
?
?
AMOUNTmoles
MOLAR MASS
6.022 x 10 23
x
x
PARTICLESmolecules
MASSgrams
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Conversions with Compounds
?
?
AMOUNTmoles
MOLAR MASS
6.022 x 10 23
x
x
PARTICLESmolecules
MASSgrams
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Grams-Moles-Molecules Conversions
Ch 7 Sec 3 Using Chemical Formulas pages 237-244
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p. 240
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Dimensional Analysis
unit given
unit given
unit wanted
x

unit given
Fill in units first then numbers !
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Dimensional Analysis
x
x
x
x

Arrange the units so that all cancel out except
the last one, which should be the one you want.
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1. How many moles of compound are there in the
following? a. 6.60 g (NH4)2SO4 b. 4.5 kg
Ca(OH)2 2. How many molecules are there in the
following? a. 25.0 g H2SO4 b. 125 g of sugar,
C12H22O11 3. What is the mass in grams of 6.25
mol of copper(II) nitrate?
Practice Page 242
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Percent Composition
(NH4)2SO4
N H S O
2 8 1 4
x 14.01 28.02 x 1.008 8.064 x 32.06
32.06 x 16.00 64.00
? 132.14 .2120 ? 132.14 .06103 ? 132.14
.2426 ? 132.14 .4843
132.144
Find the molar mass of the compound.
Divide the subtotal for each element by the molar
mass
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Percent Composition
(NH4)2SO4
N H S O
28.02 8.064 32.06 64.00
? 132.14 .2120 ? 132.14 .06103 ? 132.14
.2426 ? 132.14 .4843
x100 21.20 x100 6.103 x100 24.26 x100
48.43
132.144
Multiply each by 100 to get a percent.
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Hydrates
Salt which have the ability to bind water
molecules within their crystal lattice.
Anhydrous - salts without water Examples
CuSO4 5H2O copper(II) sulfate pentahydrate
CoCl2 6H2O cobalt (II) chloride
hexahydrate
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Hydrates
CuSO4 ? 5H2O
CoCl2 ? 6H2O
Ch 7 Sec 3 Using Chemical Formulas pages 237-244
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What percentage of sodium carbonate decahydrate,
Na2CO3 ?10H2O, is sodium carbonate?
1. Find the molar mass of Na2CO3 (the anhydrous
compound). 2. Find the mass Na2CO3 ?10H2O (the
hydrate). 3. Divide mass of compound (anhydrous)
by mass of the hydrate and multiply by 100.
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Percent Composition of a Hydrate
CuSO4 ? 5H2O
Cu S O H O
1 1 4 10 5
x 63.55 63.55 x 32.06 32.06 x 16.00 64.00
x 1.008 10.08 x 16.00 80.00
159.61
x 100 63.92
249.69
90.08
x 100 36.08
249.69
249.69
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What is the percentage of MnCl2 in MnCl2 2H2O?
77.73
How much water could 100g of anhydrous MnCl2
absorb if the hydrated form is MnCl2 2H2O?
28.64g
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1. Find the percentage compositions of the
following a. PbCl2 b. Ba(NO3)2 2.
Find the mass percentage of water in ZnSO47H2O.
3. Magnesium hydroxide is 54.87 oxygen by mass.
How many grams of oxygen are in 175 g of the
compound? How many moles of oxygen is this?
Practice Page 244
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Section 3 Homework
Ch 7 Sec 3 Using Chemical Formulas pages 237-244
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68
Modern ChemistryChapter 7Chemical Formulas and
Chemical Compounds

• Sections 1, 3 4
• Chemical Names and Formulas
• Using Chemical Formulas
• Determining Chemical Formulas

Ch 7 Sec 4 Determining Chemical Formulas pages
245-249
68
69
Monatomic ion Binary compound Nomenclature
Oxyanion Salt Formula Mass Percent
Composition Empirical Formula
Chapter Vocabulary
Ch 7 Sec 4 Determining Chemical Formulas pages
245-249
69
70
Section 4
Determining Chemical Formulas
Ch 7 Sec 4 Determining Chemical Formulas pages
245-249
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Definitions

• Empirical Formula- shows the smallest ratio of
  different atoms in a compound
• Ionic compounds- empirical formula is the
  formulas for the formula unit
• Molecular compounds- empirical formula may not be
  the formula for a molecule
• Molecular Formula- formula for a molecule a
  multiple of the empirical

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HOW TO Empirical Formula

• Get the grams from
• Convert grams to moles
• Divide all moles by the smallest mole
• If .5, multiply all by 2If .3, multiply all
  by 3If .25, multiply all by 4

grams!
Divide by the molar mass.
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Empirical Formula Example p.246
Quantitative analysis shows that a compound
contains 32.38 sodium, 22.65 sulfur, and 44.99
oxygen. Find the empirical formula of this
compound.
Ch 7 Sec 4 Determining Chemical Formulas pages
245-249
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Empirical Formula
Na S O
32.38 22.65 44.99

• 23.00g/mol1.408
• 32.06g/mol0.7065
• 16.00g/mol2.812

? 0.7065 ? 0.7065 ? 0.7065
g g g
Change to grams.
Divide the grams by the molar mass to find moles.
Divide all moles by the smallest mole.
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Empirical Formula
Na S O
1.408 moles 0.7065 moles 2.812moles
? 0.7065 1.993 ? 0.7065 1 ? 0.7065 3.980
2 1 4
Na2SO4
Divide all moles by the smallest mole.
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1. A compound is found to contain 63.52 iron and
36.48 sulfur. Find its empirical formula. 2.
Find the empirical formula of a compound found to
contain 26.56 potassium, 35.41 chromium, and
the remainder oxygen. 3. Analysis of 20.0 g of a
compound containing only calcium and bromine
indicates that 4.00 g of calcium are present.
What is the empirical formula of the compound
formed?
Practice Page 247
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Molecular Formula
n (empirical formula)molecular formula n (CH)
C6H6 n 6 n (emp. form. mass)molec.
form. mass
Molecular formula mass
n
Empirical formula mass
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HOW TO Molecular Formula

• Find the empirical formula.
• Find the molar mass of the empirical formula.
• Divide molecular formula mass by the empirical
  formula mass.
• Multiply all subscripts in the empirical formula
  by the umber found in 3.

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Molecular Formula Ex. p.248
The empirical formula of a compound of phosphorus
and oxygen was found to be P2O5. Experimentation
shows that the molar mass of this compound is
283. 89 g/mol. What is the compounds formula?
Ch 7 Sec 4 Determining Chemical Formulas pages
245-249
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Molecular Formula
P O
2 x 30.97 61.94 5 x 16.00 80.00
141.94
P2O5 x 2 P4O10
Find the molar mass of the empirical formula.
Multiply all subscripts in the empirical formula
by n.
Divide the molecular formula mass by the
empirical formula mass
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1. Determine the molecular formula of the
compound with an empirical formula of CH and a
formula mass of 78.110 amu. 2. A sample of a
compound with a formula mass of 34.00 amu is
found to consist of 0.44 g H and 6.92 g O. Find
its molecular formula.
Practice Page 249
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Section 4 Homework
Ch 7 Sec 4 Determining Chemical Formulas pages
245-249
82