Names, Formulas and Uses of Inorganic Compounds

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• Chapter 6
• Names, Formulas and Uses of Inorganic Compounds

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Classification of Chemical Compounds

• Organic Carbon-containing compounds
• Inorganic Compounds of other elements
• Naming systems (Nomenclature)
• International Union of Pure and Applied Chemistry
• IUPAC

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Determining the Formula of an Ionic Compound

• Ionic compounds contain cations and anions.
• 1. Determine the charges on the constituent
  cations and ions.
• The charge on main group cations (metal ion) is
  equal to the group number
• Group 1A 1 Li, Na, K, Rb, Cs
• Group 1B 1 Ag
• Group 2A 2 Be2, Mg2, Ca2, Sr2, Ba2, Ra2
• Group 2B 2 Zn2, Cd2
• Group 3A 3 Al3, Ga3

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Charges on Ions

• Some elements have variable charge on their
  cations
• Fe2 iron (II) ferrous
• Fe3 iron (III) ferric
• Cu copper (I) cuprous
• Cu2 copper (II) cupric

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The charge on non-metal anions can be determined
from the group number.

• The name of the element has been changed to end
  in ide.Group 17 (7A) -1 F-, fluoride Cl-,
  chloride Br-, bromide I-, iodide
• Group 16 (6A) -2 O2-, oxide S2-, sulfide Se2-,
  selenide Te2-, telluride
• Group 15 (5A) -3 N3-, nitride P3-,phosphide
  As3-, arsenide
• Group 14 (4A) -4 C4-, carbide

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Charges on Common Ions
Insert Figure 6.1
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Ionic Compounds Containing Polyatomic Ions

• Recognize the formulas, names and charges of the
  common polyatomic ions such as these
• NH4 ammonium 1
• C2H3O2- acetate -1
• SO42- sulfate -2
• PO43- phosphate -3

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STEP BY STEP PROCESS

• Identify formulas of ions involved.
• Determine the charge on each ion
• Multiply by a number each charge to achieve
  electroneutrality
• Use these multipliers as subscripts. If there
  are more than one poly atomic, use parentheses.

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Write the symbol for the cation first and the
anion second.

• Balance the charges with subscripts.
• Sodium chloride
• Na Cl-
• Charges are equal, no subscripts needed NaCl
• sodium sulfide
• Na S2-
• Need two Na to balance the 2- charge on S2-
• Subscript follows the symbol for Na Na2S

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Ionic Formulas

• Magnesium bromide
• Mg2 Br-
• Need two Br- to balance the 2 charge on Mg2
• Subscript follows the symbol for Br
• MgBr2
• Calcium Oxide
• Ca2 O2-
• Charges are equal, no subscripts needed
• CaO

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Binary Ionic Compounds

• Aluminum sulfide
• Al3 S2-
• To balance charge, multiply Al3 by 2. 2x3 6
• Multiply S2- by 3. 3x2- 6-
• Use 2 as the subscript for Al 3 as the subscript
  for S Al2S3
• Copper (II) Sulfide
• Cu2 S2-
• Charges are equal, no subscripts needed CuS

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Compounds Containing Polyatomic Ions

• Given name, write formulas for ionic compounds
  containing polyatomic ions
• ammonium chloride, NH4Cl
• ammonium sulfate, (NH4)2Cl
• sodium nitrate, NaNO3
• calcium hydroxide, Ca(OH)2
• calcium sulfate, CaSO4
• aluminum carbonate, Al2(CO3)2

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• Name binary ionic compounds.
• Given the formula of a binary ionic compound,
  name the compound and deduce the charge on the
  constituent ions.
• Li2S lithium sulfide
• FeCl2 iron(II) chloride
• copper (I) oxide Cu O2- Cu2O

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Naming Compounds with Polyatomic Ions

• Given formula, name compounds containing
  polyatomic ions.
• (NH4)2SO4, ammonium sulfate
• AlPO4, aluminum phosphate
• Fe3(PO4)2, iron(II) phosphate
• CuNO3, copper(I) nitrate
• CaCO3, calcium carbonate

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Molecular Compounds

• Given the formula of a molecular (covalent)
  compound, determine the name.
• A molecular (covalent) compound is made of two or
  more non-metals, not including the polyatomic
  ions.

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Prefixes used in naming molecular compounds

• Mono
• di
• tri
• tetra
• penta
• hexa
• hepta
• octa
• nona
• deca

• One
• two
• three
• four
• five
• six
• seven
• eight
• nine
• ten

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Determine the name of

• CO2,, carbon dioxide
• N2O4, dinitrogen tetroxide
• SF6, sulfur hexafluoride
• CCl4, carbon tetrachloride
• CO, carbon monoxide

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Some compounds have common names

• H2O water
• NH3 ammonia
• CH4 methane
• NO nitric oxide
• N2O nitrous oxide

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Oxidation Numbers

• Oxidation Number-Ion charges and apparent
  charges assigned to atoms within compounds.
• Also called Oxidation State.
• Bookkeeping system for keeping track of
  electrons.
• Transition Elements may have several different
  oxidation numbers.

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Rules for Assigning Oxidation Numbers

• Uncombined elements have an oxidation number of
  zero K, Fe, H2, O2.
• For a compound, the sum of oxidation numbers is
  zero.
• For a polyatomic ion, the sum of oxidation
  numbers is equal to the charge on the ion.
• For a monatomic ion, the charge is the oxidation
  number Na is 1, O2- is -2.

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Oxidation Number Rules (continued)

• When oxygen is present in a compound or
  polyatomic ion, it is assigned an oxidation
  number of -2 (except for peroxides like H2O2,
  where it is -1).
• Hydrogen usually has an oxidation number of 1,
  except in metal hydrides like LiAlH4.

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Steps in Determining Oxidation Numbers

• Write down the known oxidation numbers in the
  formula. Set the missing Oxidation number to x.
• Multiply the oxidation number by the subscript.
• Write an equation where the sum of the oxidation
  numbers equal zero for a compound or the charge
  for a polyatomic ion.
• Solve for the missing oxidation number.

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Example Problems

• Determine the oxidation number of the elements
  in H2SO4.
• The oxidation number of H is 1 since it is
  combined with non-metals.
• The oxidation number of O is -2 since this is not
  a peroxide.
• The sum of the oxidation numbers is 0
• Solving for x
• 0 2(1) x 4(-2) 0 -6 x x 6

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Polyatomic ion

• Determine the oxidation number of all atoms in
  the Cr2O72- ion.
• The oxidation number of O is -2. The sum of the
  oxidation numbers is -2. Substituting in to the
  formula and solving for Cr
• -2 2x 7(-2) -2 2x - 14
• 2x -14 x -14/2 -7

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Acids

• Compounds which release hydrogen ions, H, when
  dissolved in water are called acids.
• Strong acids dissolve in water completely to form
  hydronium ions, H3O and an anion
• HCl(g) H2O(l) H3O Cl-

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Weak Acids

• Weak acids ionize partially
• Acetic Acid
• HC2H3O2 H C2H3O2-
• Carbonic Acid--Formed from CO2 in H2O.
• CO2 H2O H2CO3
• H2CO3 H HCO3-

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Naming Acids

• Binary acids contain H and an anion.
• Name them as hydro---ic acids
• HCl hydrochloric acid
• Oxoacids contain hydrogen and a polyatomic anion.
• If the anion ends acid suffix is
• ate ic
• ite ous

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Oxoacids

• Examples
• acid anion anion acid
• formula formula name name
• HClO3 ClO3- chlorate chloric acid
• HNO3 NO3- nitrate nitric acid
• HC2H3O2 C2H3O2- acetate acetic acid
• H2CO3 CO32- carbonate carbonic acid

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Halogen Containing Acids and Anions

• Hydro..ic acids have no oxygen
• peric acids have the most oxygen
• ic acids and ate anions have more oxygen
  atoms than ous acids and ite anions.
• Hypoous acids have the least oxygen.

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Salts of Polyprotic Acids

• Some acids contain more than one ionizable
  hydrogen, and can lose one or more or these
  hydrogen ions when they dissolve
• H2SO4 H HSO4-
• HSO4- H SO42-
• Salts formed when one or more ionizable hydrogens
  remains are called acid salts
• NaHSO4 sodium hydrogen sulfate or
  sodium bisulfate

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Hydrates

• Hydrates are ionic compounds which have a certain
  number of water molecules associated with them.
• The number of water molecules associated with
  each formula unit is indicated with a Greek
  prefix followed by hydrate.
• CuSO4.5H2O, copper(II) sulfate pentahydrate

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Industrial Compounds

• Many Inorganic Salts and Acids have Industrial
  Importance
• H2SO4 First in chemical production, 48 million
  tons per year, 4 billion. Used in the
  production of fertilizer, processing metal ores,
  automobile batteries.
• Na2CO3 Soda Ash. 11 million tons. In laundry
  detergents, water softening, controlling acidity
  in swimming pools, manufacture of glass.