Decomposition Reactions
Definition: A decomposition reaction is a chemical reaction in which a single compound breaks down into two or more simpler substances.
General Equation:
$$ AB \rightarrow A + B $$
Types of Decomposition Reactions:
- Thermal Decomposition: Occurs when a compound breaks down due to the absorption of heat.
- Photodecomposition: Occurs when a compound breaks down due to the absorption of light energy.
- Electrolytic Decomposition: Occurs when a compound breaks down when an electric current is passed through it.
Factors Affecting Decomposition Reactions:
- Temperature: Higher temperatures generally increase the rate of decomposition.
- Surface Area: Increasing the surface area of the reactant increases the rate of decomposition.
- Pressure: Pressure has little effect on decomposition reactions involving gases.
- Catalysts: Catalysts can increase the rate of decomposition by providing an alternative reaction pathway with a lower Activation Energy.
Examples:
- Thermal Decomposition of Calcium Carbonate:
$$ CaCO_3(s) \xrightarrow{\text{heat}} CaO(s) + CO_2(g) $$
- Photodecomposition of Hydrogen Peroxide:
$$ 2H_2O_2(aq) \xrightarrow{\text{light}} 2H_2O(l) + O_2(g) $$
- Electrolytic Decomposition of Water:
$$ 2H_2O(l) \xrightarrow{\text{electricity}} 2H_2(g) + O_2(g) $$
Applications:
- Decomposition reactions are used in a variety of industrial processes, such as:
- Production of metals from their ores
- Production of gases
- Purification of substances
- Decomposition reactions also occur naturally, such as in the digestion of food and the decay of organic matter.