write down 20 chemical reactions, you observe in your
surrounding and classify them as combination, decomposition,
displacement or redox reaction.
Answers
Displacement reaction :
A single-displacement reaction, also known as a single-replacement reaction, is a reaction by which one
(or more) element(s) replaces an/other element(s) in a compound. It can be represented generally as:
A+B−C→A−C+B
All simple metal with acid reactions are single displacement reactions. For example, the reaction
between magnesium, Mg, and hydrochloric acid, HCl, forms magnesium chloride, MgCl2 , and hydrogen,H2
Mg(s)+2HCl(aq)→MgCl2 (aq)+H2 (g)
Decomposition reaction :
A decomposition reaction is a type of chemical reaction where one reactant yields two or more
products.
The general form for a decomposition reaction is
AB→A+B
Water can be separated by electrolysis into hydrogen gas and oxygen gas through the decomposition
reaction: 2H2O→2H2+O2
Another example is the spontaneous decomposition of hydrogen peroxide into water and oxygen: 2H2O2 →2H2O+O2
The decomposition of potassium chlorate into potassium chloride and oxygen is yet another example:
2KClO3→2KCl+3O2
Combination reaction :
A combination reaction (also known as a synthesis reaction) is a reaction where two or more elements
or compounds (reactants) combine to form a single compound (product). Such reactions may be
represented by equations of the following form : X+Y→XY.
Formation of calcium oxide by the combination elements calcium and oxygen.
2Ca+O2 →2CaO
Formation of ammonia by the combination of elements nitrogen and hydrogen.
N2+3H2→2NH3