question : define - decomposition reaction with three types
Answers
Decomposition reactions are chemical reactions in which a more complex molecule breaks down to make simpler ones. There are three types of decomposition reactions:
Thermal decomposition reactions;
Elctrolytic decomposition reactions;
Photo decomposition reactions.
Thermal decomposition - such reactions are usually endothermic, since energy in the form of heat is required to break the bonds of the more complex molecule. Examples include
C
a
C
O
3
(
s
)
+
heat
→
C
a
O
(
s
)
+
C
O
2
(
g
)
- calcium carbonate decomposes into calcium oxide and carbon dioxide when heated;
2
K
C
l
O
3
(
s
)
+
heat
→
2
K
C
l
(
s
)
+
3
O
2
(
g
)
- potassium chlorate decomposes into potassium chloride and oxygen gas when ehated;
2
F
e
(
O
H
)
3
+
heat
→
F
e
2
O
3
+
3
H
2
O
-ferric dioxide decomposes into ferric oxide and water when heated;
Electrolytic decomposition - such reactions occur when an electric current is passed through an aqueous solution of a compound. Two classic examples are the electrolysis of water