Question

why decomposition reactions are called the opposite of combination reaction​

Answer 1

Answer:

Decomposition reaction is called as reverse of combination reaction because in combination reaction 2 elements combine to form a compound. But in decomposition reaction a compound Is separated to its individual element back again.

Answer 2

Answer- The above question is from the chapter 'Chemical Equations and Reactions'.

Given question: Why are decomposition reactions called the opposite of the combination reaction​s?

Answer: Following are the reasons why decomposition reactions are called the opposite of combination reaction​s:-

1. Decomposition reactions are those in which one substance decomposes to form two or more products while combination reactions are those in which two or more substances combine to form a single product.

2. Decomposition reaction involves absorption of energy (endothermic reactions) while combination reaction involves release of energy (exothermic reaction).

3. Example: CaCO₃ → CaO + O₂ is a decomposition reaction.

CaO + O₂ → CaCO₃ is a combination reaction.