Decomposition Reactions
Chemical decomposition, analysis or breakdown is the separation of a chemical compound into elements or simpler compounds. It is sometimes defined as the exact opposite of a chemical synthesis. Chemical decomposition is often an undesired chemical reaction. The stability that a chemical compound ordinarily has is eventually limited when exposed to extreme environmental conditions like heat,radiation, humidity or the acidity of a solvent.
The generalized reaction for chemical decomposition is:
AB → A + B
with a specific example being the electrolysis of water to gaseous hydrogen and oxygen:
2 H2O(I) → 2 H2 + O2
Additional examples
An example of spontaneous decomposition is that of hydrogen peroxide, which will slowly decompose into water and oxygen:
2 H2O2 → 2 H2O + O2
Carbonates will decompose when heated, a notable exception being that of carbonic acid, H2CO3. Carbonic acid, the "fizz" in soda, pop cans and other carbonated beverages, will decompose over time (spontaneously) into carbon dioxide and water
H2CO3 → H2O + CO2
Other carbonates will decompose when heated producing the corresponding metal oxide and carbon dioxide. In the following equation M represents a metal:
MCO3 → MO + CO2 A specific example of this involving calcium carbonate:
CaCO3 → CaO + CO2 Metal chlorates also decompose when heated. A metal chloride and oxygen gas are the products.
2 MClO3 → 2 MCl + 3 O2 A common decomposition of a chlorate to evolve oxygen utilizes potassium chlorate as follows:
2 KClO3 → 2 KCl + 3 O2
AB → A + B
with a specific example being the electrolysis of water to gaseous hydrogen and oxygen:
2 H2O(I) → 2 H2 + O2
Additional examples
An example of spontaneous decomposition is that of hydrogen peroxide, which will slowly decompose into water and oxygen:
2 H2O2 → 2 H2O + O2
Carbonates will decompose when heated, a notable exception being that of carbonic acid, H2CO3. Carbonic acid, the "fizz" in soda, pop cans and other carbonated beverages, will decompose over time (spontaneously) into carbon dioxide and water
H2CO3 → H2O + CO2
Other carbonates will decompose when heated producing the corresponding metal oxide and carbon dioxide. In the following equation M represents a metal:
MCO3 → MO + CO2 A specific example of this involving calcium carbonate:
CaCO3 → CaO + CO2 Metal chlorates also decompose when heated. A metal chloride and oxygen gas are the products.
2 MClO3 → 2 MCl + 3 O2 A common decomposition of a chlorate to evolve oxygen utilizes potassium chlorate as follows:
2 KClO3 → 2 KCl + 3 O2
Copper Carbonate: Copper carbonate decomposes at 290 °C, giving off carbon dioxide and leaving copper(II) oxide: Copper Carbonate → Copper (II) Oxide + Carbon Dioxide CuCO3 (s) → CuO (s) + CO2 (g) |
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