Naming Compounds

1
Naming Compounds

• Binary Ionic Compounds
• Cation ( charge ) is listed first.
• Name of cation is the chemical name.
• For many transition metals, the ion is
  distinguished by the addition of a roman numeral
  after the chemical name.
• Find charge of the anion and choose appropriate
  roman numeral to balance the charge.
• Name of the anion ends in ide.
• Examples
• Al2O3 aluminum oxide
• CuBr2 copper(II) bromide

2
Naming Molecular Compounds

• Binary Molecular Compounds
• If more than one atom, name the first element
  with a numerical prefix.
• Name the second element with a numerical prefix
  and a suffix ide.
• For prefixes, drop o or a if the element name
  begins with a vowel. (Examples are monoxide and
  pentoxide.)
• Examples
• N2O4 dinitrogen tetroxide
• OF2 oxygen difluoride

3
Numerical Prefixes
Number Prefix
1 mono-
2 di-
3 tri-
4 tetra-
5 penta-
6 hexa-
7 hepta-
8 octa-
9 nona-
10 deca-
4
Polyatomic ions

• Poly many
• Atomic atoms
• Entire group of atoms is an ion with a positive
  or negative charge.
• Within the polyatomic ion, atoms are bound
  covalently.
• Examples

Carbonate ion CO3 2-
Sulfate ion SO4 2-
S
C
5
Chemical Equations

• Law of conservation of mass
• Atoms are neither created nor destroyed (in
  ordinary chemical reactions).
• number of atoms on left number of atoms on
  right
• The correct formula must be shown for all
  reactants and products.
• Use oxidation states and ionic charges to
  correctly write a formula
• In balancing, do not split up molecules or change
  the formula.
• Remember common polyatomic ions and diatomic
  molecules.

6
Symbols used in Equations

• Yields
• Reversible reaction
• Reactants are heated
• Catalyst added
• (s) solid state or precipitate
• (l) liquid state
• (g) gaseous state
• (aq) aqueous state, or dissolved in water

catalyst
7
Order for Balancing

• MINOH method (Me know chemistry, said Tarzan as
  he climbed the stoichiome-tree.)
• M - metals Balance metals first.
• I - ions Balance polyatomic ions.
• N nonmetals Balance Cl, S,N.
• O oxygen
• H hydrogen
• An odd on one side and even on other will
  require you to multiply the odd side to make it
  even!

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Steps to balance a chemical equation

• Write the formulas and symbols.
• Cu(s) Ag(NO3)(aq) Ag(s) Cu(NO3)2 (aq)
• Count the atoms on each side of the arrow.
• 1 Cu 1 Cu
• 1 Ag 1 Ag
• 1 N 2 N
• 3 O 6 O
• Balance by using coefficients.
• Do not change subscripts!
• Cu(s) 2Ag(NO3)(aq) 2Ag(s) Cu(NO3)2 (aq)
• Check work by counting each element.
• 1 Cu 1 Cu
• 2 Ag 2Ag
• 2 N 2 N
• 6 O 6 O

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Two Important Principles

• Every chemical compound has a formula that cannot
  be altered.
• A chemical reaction must account for every atom
  used.
• (Law of Conservation of Matter)

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Synthesis reactions(composition reactions)

• A B AB
• Reactions with O2 or S8
• Oxides or sulfides formed
• 16Rb S8 8Rb2S 2Mg O2 2MgO
• Metals with halogens
• Ionic compounds formed
• Examples are NaF and NaCl

11
Synthesis reactions, cont.

• A B AB
• Two compounds combine to form a single product.
• N2O3 H2O 2HNO2
• Oxides with water
• a. With metal Metal hydroxides produced
• CaO H2O Ca(OH)2
• b. With nonmetal Oxyacids produced
• SO3 H2O H2SO4

12
Synthesis reactions, cont.

• A B AB
• Metal oxides with CO2
• Carbonates produced
• CaO CO2 CaCO3
• Metal oxides with SO2
• Sulfites produced
• CaO SO2 CaSO3

13
Decomposition reactions

• AB A B
• Binary compounds split up
• Electrolysis is decomposition by electric current
• Example H2O 2H2 O2
• Electrolysis is decomposition by electric current
• Metals with carbonates
• Metal oxide and carbon dioxide are formed
• Example CaCO3 CaO CO2
• Metal hydroxides
• When heated, metal hydroxides decompose to metal
  oxide and water.
• Example Ca(OH)2 CaO H2O

electricity
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Decomposition reactions

• AB A B
• Metal chlorates
• When heated, metal chlorates decompose to metal
  chloride and oxygen.
• Example 2KClO3 2KCl 3O2
• Decomposition of acids
• Some acids decompose into nonmetal oxides and
  water.
• Example H2CO3 CO2 H2O

15
Single Replacement Reactions

• C AB A CB
• Metal replaces another metal
• Replacing metal must be the more active metal!
• Example 2Al 3Pb(NO3)2 3Pb 2Al(NO3)3
• Metal replaces H in water
• Active metals produce metal hydroxide and water
• Less reactive metals make metal oxide and
  hydrogen gas
• Examples 2Na 2H2O 2NaOH H2
• 3Fe 4H2O Fe3O4 4H2

16
Single Replacement Reactions

• C AB A CB
• Metal replaces H in an acid
• More active metals involved
• Example Mg 2HCl H2 MgCl2
• Halogen replaces another halogen
• Fluorine is most reactive and replaces others.
• Example Cl2 2KBr 2KCl Br2
• Br2 2KCl No reaction

17
Double Replacement Reactions

• AB CD AD CB
• Precipitate forms (a salt) .
• Example
• 2KI(aq) Pb(NO3)2(aq) PbI2(s) 2KNO3(aq)
• Gas forms.
• FeS(s) 2HCl(aq) H2S (g) 2FeCl2(aq)
• Water forms.
• NaOH(aq) HCl(aq) NaCl (aq) H2O (l)

18
Combustion Reactions

• CH4 2O2 ? 2H2O CO2
• One of the reactants is oxygen.
• In this class, all or our combustion reactions
  will be oxygen and hydrocarbons.
• The products of this type of combustion reaction
  will always be water and carbon dioxide.
• To quickly balance combustion reactions, START
  WITH WATER and multiply it by an EVEN coefficient.

19
Practice Balancing equations

• 1. Solid sodium combines with chlorine gas to
  produce solid sodium chloride.
• 2. When solid copper reacts with aqueous silver
  nitrate, the products are aqueous copper(II)
  nitrate and solid silver.
• 3. In a blast furnace, the reaction between
  solid iron(III) oxide and carbon monoxide gas
  produces solid iron and carbon dioxide gas.

20
Practice Balancing equations

• 1. Solid sodium combines with chlorine gas to
  produce solid sodium chloride.
• 2. When solid copper reacts with aqueous silver
  nitrate, the products are aqueous copper(II)
  nitrate and solid silver.
• 3. In a blast furnace, the reaction between
  solid iron(III) oxide and carbon monoxide gas
  produces solid iron and carbon dioxide gas.

21
Reaction types Summary

• Synthesis Reactant Product
• Oxygen Oxide
• Halogen Halide
• H2O nonmetal oxide Acid
• H2O metal oxide Base (R-OH)
• Decomposition
• Reactant Product
• Binary comp. Elements
• Metal CO3 Metal oxide CO2
• Metal OH Metal oxide H2O
• Metal ClO3 Metal chloride O2
• Acids Nonmetal oxide H2O

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Reaction types Summary, cont.

• Single replacement
• Single and a couple Couple and a single
• 1. Metal replaces metal in compound
• 2. Metal replaces H in water H2(g) product
• 3. Metal replaces H in acid H2(g) product
• 4. Halogen replaces another
• Double replacement
• 2 couples 2 different couples
• 1. Precipitate forms (s) product
• 2. Gas forms (g) product
• 3. Water forms H2O product