During combustion analysis, how does matter change when a hydrocarbon burns in oxygen, and why does this occur?

• A. The hydrocarbon decomposes into its elemental forms without interacting with oxygen because combustion is a decomposition reaction.
• B. The hydrocarbon combines with oxygen to form only water, as carbon atoms are not involved in the reaction.
• C. The hydrocarbon simply evaporates into the air without any chemical change because heat causes physical changes only.
• D. The hydrocarbon reacts with oxygen to form carbon dioxide and water because chemical bonds are broken and new ones are formed.

Answer: (D)

Verified step by step guidance

1. Understand that combustion is a chemical reaction where a hydrocarbon reacts with oxygen (O\_2) from the air.
2. Recognize that during combustion, the chemical bonds in the hydrocarbon and oxygen molecules break, and new bonds form to create different products.
3. Identify the typical products of hydrocarbon combustion: carbon dioxide (CO\_2) and water (H\_2O), which result from the carbon and hydrogen atoms combining with oxygen.
4. Explain that this transformation occurs because energy from heat breaks the original bonds, allowing atoms to rearrange into more stable molecules (CO\_2 and H\_2O).
5. Conclude that matter changes chemically during combustion, not just physically, because new substances with different properties are formed through bond breaking and formation.