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

Explanation

### Step-by-Step Solution:

1. **Understanding Combination Reactions**:
- A combination reaction is a type of chemical reaction where two or more reactants combine to form a single product.
- For example, when hydrogen gas (H₂) combines with oxygen gas (O₂), they form water (H₂O).
- The equation for this reaction is:
\[
2H_2 + O_2 \rightarrow 2H_2O
...