B. Decomposition:

• A single compound breaks down into its component parts or simpler compounds.

• Basic form: AX  -->   A  +  X

Examples of decomposition reactions:

1. Metallic carbonates, when heated, form metallic oxides and CO_2(g).

2. Most metallic hydroxides, when heated, decompose into metallic oxides and water.

3. Metallic chlorates, when heated, decompose into metallic chlorides and oxygen.

Ex. 2KClO_3(s)  -->    2KCl_(s)  +  3O_2(g)

4. Some acids, when heated, decompose into nonmetallic oxides and water.

Ex. H₂SO₄  -->    H₂O_(l)  +  SO_3(g)

5. Some oxides, when heated, decompose.

Ex. 2HgO_(s)  -->    2Hg_(l)  +  O_2(g)

6. Some decomposition reactions are produced by electricity (electrolysis)

Ex. 2H₂O_(l)  -->    2H_2(g)  +  O_2(g)

Ex. 2NaCl_(l)  -->    2Na_(s)  +  Cl_2(g)