Decomposition Reaction

A chemical decomposition reaction or analysis reaction is one of the most common types of chemical reactions. In a decomposition reaction a compound is broken into smaller chemical species.


General Form of a Synthesis Reaction

The general form of a synthesis reaction is:

AB → A + B

Examples of synthesis reactions:

    Generic Formula
 
Example
  • metal oxide → Metal + oxygen
  •         2 MgO (s) → 2 Mg (s) + O2 (g)

  • metal chlorate → metal chloride + oxygen
  •         2 MgClO3 (s) → 2 MgCl (s) + O2 (g)
  • nonmetallic oxide → nonmetal + oxygen
  •        CO2 (g) → C (s) + O2 (g)
  • metallic hydroxide → metal oxide + water
  •        Mg(OH)2 (s) → MgO (s) + H2O (l)
  • metallic carbonate → metal oxide + carbon dioxide
  •        MgCO3 (s) → MgO (s) + CO 2 (g)
  • acid → nonmetallic oxide + water
  •        H2CO3 (aq)→ CO2 (g) + H2O (l)
  • salt → metal + nonmetal
  •        2 NaCl (s) → 2 Na(s) + Cl2 (g)
  • some compounds will decompose into elements
  •        2 PCl3 (g) → 2 P (s) + 3 Cl2 (g)

    Examples:

    Reactants
    Analysis
    BCE
       MgO (s) →

    desomposition of a metal oxide produces a metal and oxygen

       2 MgO (s) → 2 Mg (s) + O2 (g)
       CaCO3 (s)
    decomposition of metal carbonate produces a metal oxide and carbon dioxide
       CaCO3 (s) → CaO (s) + CO2 (s) 
       Ca(OH)2 (s)
    dexompositoin of a metal hydroxide produces a metal oxide and water
       Ca(OH)2 (s)→ CaO (s) + H2O (l)
       H2CO3 (aq)
    decomposition of an acid produces a non-metal oxide and water
        H2CO3 (aq) → CO2 (s) + H2O (l)

       2 Fe2O3 (s)

       2 FeO (s)

    decomposition of a salt will produce a metal and a nonmetal
       2 Fe2O3 (s) → 2 Fe (s) +3 O2 (g)

     
       2 FeO (s) → 2 Fe (s) + O2 (g)