2. It is a reaction takes place when two or more
elements combine to form more complex
substance.
Gen. Formula
A + B AB
3. Metal + non metals Salt
Mg 2 + Cl1 MgCl2
Cu + O2 CuO
Metal + Oxygen Metal Oxide
Fe4 + O2 Fe2O4
Mg + O MgO
4. Metal oxide +Water Metal Hydroxide
Fe2O4 + H2O Fe(OH)4
Cu2O + H2O CuOH
Non-metal + Oxygen Non-metal oxide
C + O2 CO2
N3 + O2 N2O3
5. Non-metal oxide + Water Oxyacid
CO2 + H2O H2CO3
SO2 + H2O H2SO3
Metal Oxide + Non-metal Oxide salt
MgO + CO2 MgCO3
MgO + SO3 MgSO4
6. In decomposition reaction , one substance
, usually undergoes a reaction to form two or
more substances which may be elements or
compound.
This process usually requires heat to
complete the reaction
AB A + B
7. A. When an oxide is heated, generally oxygen is
given off as one of the products.
1. HgO Hg + O2
2. KClO3 KCl + O2
8. When nitrates are heated, it produces nitrites
and oxygen.
KNO3 KN O2 + O2
9. Some carbonates like limestone when
heated, decompose to yield CO2.
CaCO3 CaO + CO2
MgCO3 MgO + CO2
10. Some compounds such as baking soda (
sodium hydrogen carbonate or sodium
bicarbonate ) when decompose will yield
carbon dioxide, water and carbonate salt
2NaHCO3 Na2CO3+H2O +CO2
2KHCO3 K2CO3 +H2O +CO2
11. Hydrates are substances that contain on e or
more molecules of water for each formula
units.These compounds, upon application of
heat, readily decompose.The water is driven
off leaving the anhydrous(without water) salt.
Na2CO3 + H2O Na2CO3 +H2O
