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Reaction Review
AP Chemistry
5 Basic Types from pre-AP chemistry
DECOMPOSITION REACTIONS
A. Metallic carbonates, when heated, decompose into metallic oxides and carbon dioxide.
1. MgCO3  MgO + CO2
Complete word equations and write balanced formula equations for the following.
2. Aluminum carbonate aluminum oxide + carbon dioxide
Al2(CO3) 3 Al2O3 + 3 CO2
3. Strontium carbonate  strontium oxide + carbon dioxide
SrCO3  SrO + CO2
4. Copper (I) carbonate  copper (I) oxide + carbon dioxide
Cu2CO3  Cu2O + CO2
B. Metallic chlorates, when heated, decompose into metallic chlorides and oxygen.
1. 2KClO3  2KCl + 3O2
Complete word equations and write balanced formula equations for the following.
2. Iron (III) chlorate  iron (III) chloride + oxygen
2 Fe(ClO3) 3  2 FeCl3 + 9 O2
3. Barium chlorate  barium chloride + oxygen
Ba(ClO3) 2  BaCl2 + 3 O2
4. Cesium hypochlorite  cesium chloride + oxygen
2 CsClO3  2 CsCl + 3 O2
5. Zinc perchlorate  zinc chloride + oxygen
Zn(ClO4) 2  ZnCl2 + 4 O2
C. Many metallic hydroxides, when heated, decompose into metallic oxides (basic anhydride) and water.
1. Ca(OH)2  CaO + H2O
Complete word equations and write balanced formula equations for the following.
2. Sodium hydroxide sodium oxide + water
2 NaOH  Na2O + H2O
3. Chromium (III) hydroxide  chromium (III) oxide + water
2 Cr(OH) 3  Cr2O3 + 3 H2O
4. Manganese (IV) hydroxide  manganese (IV) oxide + water
Mn(OH)4  MnO2 + 2 H2O
D. Some metallic oxides, when heated, decompose into the metal and oxygen.
1. 2K2O  2K + O2
Complete the word equation and write balanced formula equations for the following.
2. Zinc oxide  Zinc + oxygen
2 ZnO  2 Zn + O2
3. Lead (II) oxide  lead + oxygen
2 PbO  2 Pb + O2
4. Copper (II) oxide  copper + oxygen
2 CuO  2 Cu + O2
E. Some acids decompose into nonmetallic oxides (acid anhydride) and water.
1. H2CO3  CO2 + H2O
Complete word equation and write balanced formula equations for the following.
2. Sulfurous acid  sulfur dioxide + water
H2SO3  SO2 + H2O
3. Sulfuric acid sulfur trioxide + water
H2SO4  SO3 + H2O
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SYNTHESIS REACTIONS
A. Element + Element  Compound
1. Fe + O2 
Fe2O3
Complete the word equation and write the balanced molecular equation in the space below.
2. magnesium + oxygen  magnesium oxide
2 Mg + O2  2 MgO
3. sodium + chlorine  sodium chloride
2 Na + Cl2  2 NaCl
B. Compound + Compound  different compound
1. Metal oxide + carbon dioxide  metal carbonate (NOTICE: reverse of decomposition!)
Ex. Sodium oxide + carbon dioxide  sodium carbonate
Na2O + CO2 
Na2CO3
b) calcium oxide + carbon dioxide  calcium carbonate
CaO + CO2 
CaCO3
2. metal oxide + water  base (metal hydroxide) (metal oxide = basic anhydride)
a) iron (II) oxide + water  iron (II) hydroxide
FeO + H2O  Fe(OH)2
b) lithium oxide + water  lithium hydroxide
Li2O + H2O  2 LiOH
3.
Nonmetal oxide + water  acid (hydrogen + polyatomic)(Nonmetal oxide = acidic anhydride)
a) SO3 + H2O  H2SO4
b) N2O3 + H2O  2HNO2
COMBUSTION REACTIONS
Fuel (organic: alkanes, alcohols, etc.) + oxygen  carbon dioxide + water
A. methane + oxygen  carbon dioxide + water (vapor)
CH4
+ O2
 CO2
+ H2O
Complete the word equation and write the balanced molecular equation in the space below.
B. ethane + oxygen  carbon dioxide + water
C3H8 + 5 O2  3 CO2 + 4 H2O
C. pentane + oxygen  carbon dioxide + water
C5H12 + 8 O2  5 CO2 + 6 H2O
D. butyl alcohol (butanol) + oxygen  carbon dioxide + water
2 C4H9OH + 13 O2  8 CO2 +10 H2O
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(Molecular Equations first time; save net ionic for later)
SINGLE REPLACEMENT REACTIONS (Activity Series)
A. More active metal atoms will replace less active metal ions from compounds to form less active metal atoms
and compounds containing the more active metal ions. Few may be no reaction. Probably not necessary any
more.
1. Lithium + sodium acetate  Lithium acetate + sodium
Li + NaC2H3O2  Li C2H3O2 + Na
Complete the word equations and write balanced formula equations for the following.
2. Silver + copper (II) nitrate  NO Reaction
3. Calcium + Magnesium phosphate  Calcium phosphate + magnesium
3 Ca + Mg3(PO4)2  3 Mg + Ca3(PO4)2 
4. Cadmium + Copper (I) sulfate Cadmium sulfate + copper
Cd + Cu2SO4  CdSO4 + 2 Cu
B. Metals in group I and in group II (calcium & below) will replace hydrogen from water, forming hydrogen
and the metallic hydroxide.
1. Sodium + water  sodium hydroxide + hydrogen
2 Na + 2 H2O  2 NaOH + H2
Complete word equations and write balanced formula equations for the following.
2. potassium + water  potassium hydroxide + hydrogen
2 K + 2 H2O  2 KOH + H2
3. magnesium + water NO reaction
4. calcium + water calcium hydroxide + hydrogen
Ca + 2 H2O  Ca(OH)2 + H2
5. zinc + water NO reaction
C. Metals above hydrogen in the activity series will replace hydrogen from most acids, forming hydrogen and
the corresponding metal compound; those below hydrogen will not react.
1. zinc + hydrochloric acid  zinc chloride + hydrogen
Zn + 2 HCl  ZnCl2 + H2
Complete word equations and write balanced formula equations for the following.
2. copper and sulfuric acid  NO reaction
3. iron + sulfuric acid iron (II) sulfate + hydrogen
4. magnesium + hydrochloric acid magnesium chloride + hydrogen
D. More active halogen atoms will replace less active halogen ions from compounds to form less active
halogen atoms and compounds containing the more active halogen ions.
1. fluorine + sodium chloride  sodium fluoride + chlorine
F2 + 2 NaCl  2 NaF + Cl2
Complete word equations and write balanced formula equations for the following.
2. sodium fluoride + chlorine NO reaction
3. aluminum iodide + bromine aluminum bromide + iodide
2 AlI3 + 3 Br2  2 AlBr3 + 3 I2
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(Molecular Equations first time; save net ionic for later)
DOUBLE REPLACEMENT (DOUBLE DISPLACEMENT)
There are three driving forces in double replacement reactions. They are the formation of a covalent compound
such as water, the formation of a gas, or the formation of a precipitate. Unless one of these three products is
formed, a double replacement reaction will probably not occur. Watch out for products that decompose easily.
Complete the word equations and write balanced formula equations for these potential reactions.
THEN decide if the reaction would occur. If it doesn’t, cross out the products of the formula equation and write
NO REACTION.
1. nickel (II) sulfate + calcium phosphate nickel (II) phosphate + calcium sulfate
3 NiSO4 + Ca3(PO4)2  3 CaSO4 + Ni3(PO4)2
2. barium hydroxide + ammonium chloride barium chloride + ammonia + water
Ba(OH)2 + 2 NH4Cl  BaCl2 + 2 NH3 +H2O
3. lead (II) nitrate + potassium dichromate lead (II) dichromate + potassium nitrate
Pb(NO3)2 + K2Cr2O7  2 KNO3 + PbCr2O7
4. silver nitrate + sodium chloride sodium nitrate + silver chloride
AgNO3 + NaCl  NaNO3 + AgCl
5. sodium hydroxide + hydrochloric acid sodium chloride + water
NaOH + HCl  NaCl + HOH
6. sodium hydrogen carbonate + acetic acid sodium acetate + carbon dioxide + water
NaHCO3 +HC2H3O2  Na C2H3O2 + H2O + CO2
7. sodium carbonate + hydrosulfuric acid sodium sulfide + water + carbon dioxide
Na2CO3 + H2S  Na2S + H2O + CO2
8. ammonium chloride + sodium hydroxide ammonia + water + sodium chloride
NH4Cl + NaOH NH3 + H2O + NaCl
9. potassium carbonate + hydrochloric acid potassium chloride + water + carbon dioxide
K2CO3 + 2 HCl  2 KCl + H2O + CO2
10. sodium fluoride + silver nitrate sodium nitrate + silver fluoride
NaF + AgNO3  NaNO3 +AgF