Chemical Reactions and Types

Study Notes

Chemical reactions involve the motion of electrons, leading to the formation or breaking of chemical bonds.
They can be classified as: combination or synthesis reactions, decomposition reactions, single and double displacement reactions, oxidation and reduction.

In combination reactions, two or more substances combine to form a new single substance under suitable conditions.
They can be classified into three types:
- Reactions between two or more elements (e.g., hydrogen combining with oxygen to form water).
- Reactions between two or more compounds (e.g., carbon dioxide dissolving in water to form carbonic acid or soda water).
- Reactions between an element and a compound (e.g., carbon monoxide reacting with oxygen to form carbon dioxide).

In a decomposition reaction, a single compound splits into two or more simple substances under suitable conditions such as heat, light, or electricity.
Decomposition reactions are classified into three types:
- Thermal decomposition (e.g., copper (II) carbonate decomposing into copper (II) oxide and carbon dioxide gas when heated).
- Electrolytic decomposition (e.g., electrolysis of water resulting in the separation of hydrogen and oxygen).
- Photo decomposition (e.g., silver chloride decomposing into silver and chlorine gas in the presence of sunlight).

Chemical reactions involve the motion of electrons, leading to the formation or breaking of chemical bonds.
They can be classified into five types: combination, decomposition, single and double displacement, oxidation, and reduction reactions.

Involve two or more substances combining to form a new single substance under suitable conditions.
Classified into three types:
- Reactions between two or more elements (e.g., 2H2 + O2 → 2H2O).
- Reactions between two or more compounds (e.g., CO2 + H2O → H2CO3).
- Reactions between an element and a compound (e.g., 2CO + O2 → 2CO2).

Involve a single compound splitting into two or more simple substances under suitable conditions (heat, light, or electricity).
Classified into three types:
- Thermal decomposition (e.g., CuCO3 → CuO + CO2, when heated).
- Electrolytic decomposition (e.g., 2H2O → 2H2 + O2, through electrolysis).
- Photo decomposition (e.g., 2AgCl → 2Ag + Cl2, in sunlight).