What type of change is combustion?

Options

A. chemical irreversible change
B. physical irreversible change
C. chemical reversible change
D. physical reversible change

Answer

**Solution:**

Combustion is a type of chemical change. Here’s how we can understand this:

1. **Definition of Combustion**: Combustion is a chemical reaction that typically involves a substance reacting with oxygen to produce heat and light. For example, when methane (CH₄) combusts in the presence of oxygen, it produces carbon dioxide (CO₂) and water (H₂O) along with energy in the form of heat and light.

2. **Chemical Change Characteristics**: In a chemical change, the original substances undergo a transformation to form new substances. This transformation involves a change in the chemical composition of the reactants. In the case of combustion, methane and oxygen react to form carbon dioxide and water, which are entirely different substances from the original reactants.

3. **Irreversibility of Combustion**: The change that occurs during combustion is irreversible. Once methane is burned, it cannot be converted back into methane from the carbon dioxide and water produced. This means that the original substances cannot be recovered from the products of the reaction.

4. **Conclusion**: Therefore, combustion is classified as a chemical change that is irreversible. It cannot be categorized as a physical change, as physical changes do not involve the formation of new substances.

**Final Answer**: Combustion is a chemical change and it is irreversible.

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