Why are decomposition reactions called the opposite of combination reactions? Write equations for these reactions.

Decomposition reactions are chemical reactions in which a single compound breaks down into two or more simpler substances.
These reactions are characterized by the breakdown of a complex molecule into simpler molecules or elements. They usually require the input of energy, such as heat, light, or electricity.
Decomposition reactions are essentially the reverse of combination reactions, where two or more substances combine to form a more complex compound.
Example Decomposition Reaction:

Decomposition of hydrogen peroxide:
2H2O2 (hydrogen peroxide) → 2H2O (water) + O2 (oxygen gas)
Combination Reactions:

Combination reactions, also known as synthesis reactions, are chemical reactions in which two or more substances combine to form a more complex compound.
These reactions typically release energy and are associated with the formation of new bonds between atoms or ions to create a more stable compound.
Combination reactions are the opposite of decomposition reactions, where a single compound is broken down into simpler substances.
Example Combination Reaction:

Formation of water by the combination of hydrogen and oxygen:
2H2 (hydrogen gas) + O2 (oxygen gas) → 2H2O (water)
In summary, decomposition reactions involve the breakdown of complex compounds into simpler substances, often requiring an input of energy, while combination reactions involve the formation of more complex compounds by combining simpler substances, usually releasing energy. These two types of reactions are often considered opposites in terms of the processes they represent.