Types of Reactions

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Types of Reactions
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Combustion

• Produce a flame
• Hydrocarbons react with oxygen to produce
• CO2 H2O
• Also true with oxygen containing derivatives
• CH3OH O2 ? CO2 H2O (unbalanced)

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• the cmpnd contains product will be
• a metal the metal oxide
• carbon carbon dioxide, CO2
• hydrogen water, H2O
• sulfur sulfur dioxide, SO2

Solid copper (II) sulfide is heated strongly in
oxygen gas CuS O2 ? CuO SO2 Carbon
disulfide vapor is burned in excess oxygen. CS2
O2 ? CO2 SO2 Ethanol is completely burned in
air. C2H5OH O2 ? CO2 H2O
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Decomposition

• One substance undergoes a reaction to produce two
  or more substances
• Often occurs when heated
• Metal Oxides ? free metal O2
• ? metal oxide O2
• Metal carbonates ? metal oxide CO2
• H2CO3 ? H2O CO2
• Chlorates ? metalchloride Oxygen
• KClO3 ? KCl O2

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Complexation Ligands

• Each type of metal ion has a characteristic
  coordination number
• Ag 2 (monodentate) ligands
• Zn2 and Cu2 4 ligands
• Al3 and Fe3 6 ligands.
• ligands refers to of complexes

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Ammonia, NH3

• A concentrated solution of ammonia is added to a
  solution of copper (II) chloride.
• Cu2 NH3 ? Cu(NH3)42
• Ammonia complexes can be broken by adding acid to
  form the ammonia ion
• Dilute hydrochloric acid is added to a solution
  of diamminesilver (I) nitrate.
• H Cl- Ag(NH3)2 ? NH4 AgCl

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Thiocyanate, SCN-

• Thiocyanate forms a dark red complex with iron,
  Fe3
• A solution of ammonium thiocyanate is added to a
  solution of iron (III) chloride.
• Fe3 SCN- ? Fe(SCN)63-

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Thiosulfate, S2O32-

• Thiosulfate forms complexes with any metal ions
• A solution of sodium thiosulfate is added to a
  precipitate of silver iodide.
• AgI S2O32- ? Ag(S2O3)23- I-

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Single Dis/Replacement

• Replacement of
• Metals by another metal
• Hydrogen in water by a metal
• Hydrogen in an acid by a metal
• Halogens by more active halogens

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The Activity Series of the Metals Lithium
Potassium Barium Calcium Sodium
Magnesium Aluminum Zinc Chromium Iron
Cobalt Nickel Tin Lead Hydrogen
Bismuth Copper Silver Mercury
Platinum Gold

• Metals can replace other metals provided that
  they are above the metal that they are trying to
  replace.
• Metals above hydrogen can replace hydrogen in
  acids.
• Metals from sodium upward can replace hydrogen in
  water

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The Activity Series of the Halogens
Fluorine Chlorine Bromine Iodine

• Halogens can replace other halogens in compounds,
  provided that they are above the halogen that
  they are trying to replace.
• 2NaCl(s) F2(g) ? 2NaF(s) Cl2(g)
• MgCl2(s) Br2(g) ? No Reaction

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Products that decompose

• H2CO3 ? H2O CO2
• H2SO3 ? H2O SO2
• NH4OH ? H2O NH3

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Double Replacement Reactions

• The ions of two compounds exchange places in an
  aqueous solution to form two new compounds.
• AX BY ? AY BX
• One of the compounds formed is usually a
  precipitate (an insoluble solid), an insoluble
  gas that bubbles out of solution, or a molecular
  compound, usually water.

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Occur in aqueous solns

• Solns with water
• The polarity of water creates dipole-ion
  interactions to dissolve ionic compounds
• Process is called hydration
• Tends to cause salts to fall apart in water
• Dissolved ions become hydrated (surrounded by
  water molecules) and move around independently.
• The degree to which dissolving occurs is a
  substances solubility (g/100mL)

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Solubility

• Degree of solubility depends on the strength of
  attractive forces of ions in solution
• Use rules (much be memorized ?) to predict
  products of reactions
• Remember like dissolves like
• polar molecules dissolve in water because of
  h-bonds and dipole interactions

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Exceptions
Salts
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Precipitation Reactions

• When 2 solns are mixed, an insoluble product is
  sometimes formed.
• Solid forms from two liquids
• SolidPrecipitate

If youre not part of the solution youre part of
the precipitate.
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Double replacement forming a precipitate
Double replacement (molecular) equation
Pb(NO3)2(aq) 2KI(aq) ? PbI2(s) 2KNO3(aq)
Complete Ionic Equation shows compounds as
aqueous ions
Pb2(aq) 2 NO3-(aq) 2 K(aq) 2 I-(aq) ?
PbI2(s) 2K(aq) 2 NO3-(aq)
Net Ionic Equation eliminates the spectator ions
Pb2(aq) 2 I-(aq) ? PbI2(s)
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Complete the following

• K2CrO4(aq) Ba(NO3)2(aq) ? ???
• Split the reactants into ions
• 2K(aq) CrO4-2(aq) Ba2(aq) 2 NO3-(aq) ?
• BaCrO4 2KNO3-
• Separate soluble compounds
• 2K(aq) CrO4-2(aq) Ba2(aq) 2 NO3-(aq) ?
• BaCrO4(s) 2K(aq) 2 NO3-(aq)

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• Eliminate spectator ions
• 2K(aq) CrO4-2(aq) Ba2(aq) 2 NO3-(aq) ?
• BaCrO4(s) 2K(aq) 2
  NO3-(aq)
• Write the Net Ionic Equation
• CrO4-2(aq) Ba2(aq) ? BaCrO4(s)

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Write the net ionic equation for

• 1. iron (III) sulfate and potassium sulfide
• 2. silver nitrate and potassium chloride