Classifying Chemical Reactions
Determining reaction types and
predicting products of chemical
equations.
Reaction Types
• There is an unlimited number of reactions that
may occur in the real world.
• To make learning them easier, we classify
them according to what is taking place.
• Makes predicting products MUCH easier.
Combustion Reactions
• Often used to generate energy.
• Combustion Reaction – the oxidation of an
organic compound, in which heat is released.
• One reactant is a hydrocarbon and the other
must be ______________.
• Products are always carbon dioxide and water.
Combustion Reactions
Examples:
___C3H8 + ___O2  ___H2O + ___CO2
___C2H5OH + ___
 ___
Write down the combustion of CH4
+ ___
Synthesis Reaction
• The word synthesis means “to put together”
• Synthesis Reaction – a reaction in which two
or more substances combine to form a new
compound.
• The reactants in many of these reactions are
two elements or two small compounds.
Synthesis Reactions
C + O2  CO2
2C + O2  2CO
CaO(s) + H2O(l)  Ca(OH)2(s)
Predict the products of the following synthesis rxns:
K + Cl2 
Mg + O2 
Decomposition Reaction
• Decomposition reactions are the opposite of
synthesis reactions – they have only one
reactant.
• In a decomposition reaction, a single
compound breaks down, often with the input
of energy, into two or more elements or
simpler compounds.
Decomposition Reactions
Water breaks down into its simpler components
when introduced to electricity:
Electricity
2H2O(l) ---------> 2H2(g) + O2(g)
Compounds made up of three or more elements
usually do not decompose into those elements.
Heat
CaCO3(s) -------> CaO(s) + CO2(g)
Practice So Far:
• Predict the product(s) and write a balanced
equation for each of the following reactions:
– The reaction of butane, C4H10, with oxygen.
– The reaction of water and calcium oxide
– The reaction of lithium with oxygen
– The decomposition of carbonic acid.
Displacement Reactions
• Single displacement (replacement) reaction– A single element reacts with a compound and
displaces another element of the same charge
from the compound.
• Examples:
2Al(s) + 3CuCl2(aq)  2AlCl3(aq) + 3Cu(s)
• Predict the following products:
CuSO4(aq) + Zn(s) 
Activity Series, Page 281
• Used to make predictions about displacement
reactions.
• In the activity series, elements are arranged in
order of activity with the most active on top.
• In general, an element can displace those
listed below it but not those above it.
• You could also predict that no reaction will
happen, such as when silver is put into a
copper (II) nitrate soln.
Displacement Reactions
• Double displacement (replacement) reaction– Two compounds react with one another and swap
cations / anions.
• Examples:
HCl(aq) + NaOH(aq)  HOH(l) + NaCl(s)
• Predict the following products:
Cu(NO3)2(aq) + Al2(SO4)3(s) 
Practice Classifying Reactions
• Balance each of the equations below, and
indicate the type of reaction for each equation
___Cl2(g) + ___NaBr(aq)  ___NaCl(aq) + ___Br2(l)
___CaO(s) + ___H2O  ___Ca(OH)2(aq)
___Ca(ClO3)2(s)  ___CaCl2(s) + ___O2(g)
Practice Classifying Reactions
• Balance each of the equations below, and
indicate the type of reaction for each equation
___C8H18(l) + ___O2(g)  ___CO2(g) + ___H2O(l)
__Zn(s) + __CuBr2(aq)  __ZnBr2(aq) + __Cu(s)
__AgNO3(aq) + __K2SO4(aq)  __Ag2SO4 + __KNO3(aq)
Practice With Activity Series
• Predict whether a reaction would occur when
the materials indicated are brought together.
For each reaction that would occur, complete
and balance the equation.
___Ag(s) + ___H2O(l)
___Mg(s) + ___Cu(NO3)2(aq)
___Al(s) + ___O2(g)
___H2SO4(aq) + ___KOH(aq)
Predicting Products
• Predict the products, write a balanced
equation, and identify the type of reaction for
each of the following reactions.
HgO 
C3H7OH + O2 
Zn + CuSO4 
Predicting Products
• Predict the products, write a balanced
equation, and identify the type of reaction for
each of the following reactions.
BaCl2 + Na2SO4 
Zn + F2 
C5H10 + O2 
• Naming is all that is left
• Test Coming up!!
• Start Practicing NOW!
– Describing, Balancing,
and Classifying Reactions