Chemical Equations
and Types of Reactions
and Balancing
By:
Jake Lindner
Jorge Velasquez
Chemical Reaction
1. Combustion
2. Synthesis
3. Decomposition
4. Single Displacement
5. Double Displacement
6. Acid-Base
Combustion
• Combustion reactions occur when a hydrocarbon reacts with
oxygen gas, they produce heat.
• Also known as burning
• The “Fire Triangle” is what
makes a fire possible.
Synthesis
• A Synthesis reaction occurs when two substances (generally
elements) combine and form a compound.
• Reactant + Reactant = 1 Product
• A + B = AB
• Examples:
– 2H2 + O2  2H2O
– C + O2  CO2
Decomposition
• Decomposition reactions occur when a compound breaks up into
the elements or in a few to simpler compounds.
• In other words it’s the opposite of a Synthesis reaction.
• AB  A + B
• Examples:
– 2 H2O  2H2 + O2
– 2 HgO  2Hg + O2
Decomposition Exceptions
• Carbonates and chlorates are special case decomposition reactions
that do not go to the elements.
• Chlorates (ClO3-) decompose to oxygen gas and a metal chloride
– Example: 2 Al(ClO3)3  2 AlCl3 + 9 O2
• Carbonates (CO32-) decompose to carbon dioxide and a metal oxide
– Example: CaCO3  CO2 + CaO
Single Replacement
• Single Replacement Reactions occur when one element replaces
another in a compound.
• A metal can replace a metal (+)
OR
• A nonmetal can replace a nonmetal (-).
• element + compound  product + product
• A + BC  AC + B (if A is a metal)
OR
• A + BC  BA + C (if A is a nonmetal)
Double Replacement
• Double Replacement Reactions occur when a metal replaces a metal
in a compound and a nonmetal replaces a nonmetal in a compound
• Compound + compound  product + product
• AB + CD  AD + CB
• Example:
– AgNO3 + NaCl  AgCl + NaNO3
– K2SO4 + Ba(NO3)2  KNO3 + BaSO4
Acid-Base
• Acid-Base reactions are simply double replacement reaction in
which water is produced from the H+ ion from the acid and the
OH- ion in the base.
Balancing
“The art of keeping things equal”
- Jake
Balancing
• Why Balance????
– Everyone's question in class
• Now I’ll show you a simple
guide to balancing.
• Thanks to:
• The law of conservation of
mass states that no atoms can
be created or destroyed in a
chemical reaction, so the
number of atoms that are
present in the reactants has to
balance the number of atoms
that are present in the
products.
http://www.wikihow.com/Balanc
e-Chemical-Equations
Step 1
• Write down the number of
atoms per each element that
you have on each side of the
equation.
Step 2
• Figure out what is different in
the amounts.
Step 3
Change Carbon first (multiply)
Then change the rest (multiply)
Step 4
• You now need to check the left
side and see if anything
changed.
• If it has changed just multiply
again to fix it.
• (This may not work the first
time around, you may have to
try again)
Practice Problem
• ____ N2 + ____ H2  ____ NH3
• 1 N2 + 3 H2  2 NH3
• ___ KClO3  ___ KCl + ___ O2
• 2 KClO3  2 KCl + 3 O2
• ____ NaCl + ____ F2  ____
NaF + ____ Cl2
• 2 NaCl + 1 F2  2 NaF + 1 Cl2
• ____ H2 + ____ O2  ____ H2O
• 2 H2 + 1 O2  2 H2O
The End
Jake Lindner
Jorge Velasquez