Download Types of Chemical Reactions

Types of Chemical Reactions
Most chemical reactions can be grouped into four
categories.
 synthesis
 decomposition
 single displacement
 double displacement
Understanding these types of reactions, we can predict
products of unknown reactions.
Synthesis Reaction: two or more reactants combine to
produce a new product. (put together)
A + B  AB
+
e.g.
 2H2 + O2  2H2O
 HCl + NH3  NH4Cl
Decomposition Reactions: splitting of a large compound
into elements or smaller compounds. (take apart)
AB  A + B
+
e.g.
 2H2O  2H2 + O2
 NH4NO3  N2O + 2H2O
Decompositions can be thought of as the opposite to a
synthesis reaction.
Single Displacement Reactions: one element displaces
another element from a compound.
There are two general formulas:
Z + AB  A + ZB
AB + Y  AY + B
+
e.g.
 Mg + 2AgNO3  2Ag + Mg(NO3)2
(metals replacing metals)
 CaI2 + Br2  CaBr2 + I2
(non-metals replacing non-metals)
+
Double Displacement Reactions: elements in different
compounds displace each other or exchange places.
AB + XY  AY + XB
Where A and X are
cations and B and Y are
anions. B and Y simply
change places.
+
e.g.
 Pb(NO3)2 + 2KI  PbI2 + 2KNO3
+
Everyday examples: Balance each equation and write the type of reaction on the line
rusting of iron metal
____Fe + ____O2
____Fe2O3
___________________
hearing aid battery reaction
____HgO + ____Zn
___ ZnO + ____ Hg
___________________
electrolysis of water to make hydrogen fuel
____H2O
____ H2 + ____ O2
___________________
plating silver on copper
___AgNO3 + ___Cu
___Cu(NO3)2 + ___Ag
___________________
carbon dioxide in atmosphere dissolving in oceans and changing to carbonic acid
____CO2 + ____ H2O
____H2CO3
___________________
hydrochloric acid neutralized using a base sodium hydroxide (acid-base reaction)
____HCl + ____ NaOH
____NaCl
+ ____ H2O
___________________
PRACTICE: REACTION TYPES
For each of the following chemical reactions
a) balance the skeleton equation;
b) classify by writing synthesis , decomposition, single displacement or double
displacement on the line
1.
Fe
+
O2
Fe2O3
_____________________
2.
H2
+
O2
H2O
_____________________
3.
Zn
+
HCl
H2
4.
Ca
+
HBr
5.
Mg(ClO3)2
6.
CaO
+
7.
N2O5
+
8.
NH4ClO4
9.
Al
10.
Na2S
+
+
H2O
+
ZnCl
_____________________
CaBr2 +
H2
_____________________
MgCl2
O2
_____________________
+
Ca(OH)2
H2O
_____________________
HNO3
_____________________
N2 + Cl2 + O2 + H2O
CuSO4
HBr
Al2(SO4)3 + Cu
NaBr
+
H2S
_____________________
_____________________
_____________________
A.
Write a skeleton equation.
B.
Balance the skeleton equation.
C.
Identify the type of reaction.
1.
Solid iron reacts with aqueous copper (I) nitrate to produce solid copper and
aqueous iron (II) nitrate.
2.
Aqueous potassium iodide reacts with chlorine gas to produce aqueous
potassium chloride and iodine gas.
3.
Solid aluminum reacts with solid sulfur to produce solid aluminum sulfide.
4.
Solid potassium chlorate (KClO3) decomposes to form potassium chloride and
oxygen gas.