The Five Types of Chemical Reactions
Plus 1
Chemical Equations
Fe2O3 = rust
Aluminum powder
What happens when you mix rust and aluminum?
Chemical Equations
Fe2O3 + 2Al
→
2Fe + Al2O3
Thermite Reaction
Chemical Equations
Fe2O3 + 2Al
→
2Fe + Al2O3
Thermite Reaction
This is a single replacement reaction
CuO + Al  Cu + Al2O3
• Balance the reaction
• 3CuO + 2Al  3Cu + Al2O3
• What are the oxidation states?
+2 -2
0
0
+3 -2
• CuO + Al  Cu + Al2O3
Classifying Reactions
• Five main types plus one:
•
•
•
•
Synthesis
Decomposition
Single displacement
Double displacement
• Acid/Base Neutralization
• Combustion
Synthesis Reaction
• Two or more substances combine to form
another substance.
– For example: A + B  AB
– 2H2 + O2  2H2O
– 2 or more simpler substances  one more complex
substance
Synthesis Reaction
• 2Fe + 3O2  2Fe2O3
Synthesis
Decomposition Reactions
• Opposite of synthesis.
– One substance breaks down into 2 or more other
substances.
– AB  A + B
– 2H2O2  2H2O + O2
– One compound 2 or more simpler substances
– 2H2O
electricity
2H2 + O2
Decomposition Reaction
Single Replacement Reaction
• One element replaces another element in a compound
– A + BC  AC + B
– Element + compound  new element + new compound
– Zn + CuSO4  ZnSO4 + Cu
Double Replacement Reactions
• Positive ion of one compound replaces the
positive ion of the other
– AB + CD  AD + CB
– 2 compounds 2 new compounds
AgNO3 (aq) + NaCl (aq) → AgCl (s) + NaNO3 (aq)
– Forms precipitate, covalent compound, or gas
Acid/Base Neutralization
• Acid/Base neutralization is a subcategory of
double replacement.
• An acid and base come together to form water
and a salt.
• Example;
• HCl + NaOH  NaCl + H2O
Combustion
• Reaction of a substance with oxygen. The oxygens
will attach to both molecules.
– If it is combustion of a hydrocarbon, you always get
CO2 and H2O (both gases)
– Oxygen (O2) is always a reactant.
C3H8 + 5 O2 → 3 CO2 + 4 H2O + heat
Video
• http://www.youtube.com/watch?v=tE4668aarck