What is a chemical change? Explain with an example.

Explanation

### Step-by-Step Text Solution

1. **Definition of Chemical Change**: A chemical change is a process where one or more substances undergo a transformation to form new substances with different properties. This change is often irreversible, meaning that the original substances cannot be easily recovered.

2. **Formation of New Substances**: During a chemical change, the original substances (reactants) undergo a reaction that results in the creation of new substances (products). These new substances have different physical and chemical properties compared to the reactants.

3. **Example of Chemical Change**: A classic example of a chemical change is the reaction between hydrogen gas and oxygen gas to form water.
- **Chemical Reaction**: When hydrogen (H₂) and oxygen (O₂) are mixed and ignited, they react to form water (H₂O).
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