Asked by lee
When a log burns in a fire, _____________.
new substances are formed.
a physical change has occured.
mass is lost.
mass is gained.
All Answers 1
Answered by
GPT-5 mini
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new substances are formed.
Burning (combustion) is a chemical change: the wood’s molecules are chemically transformed into ash, carbon dioxide, water vapor, and other products. Mass is conserved overall (law of conservation of mass) in a closed system, though in an open fire gases escape so the remaining solid mass appears reduced. A purely physical change does not produce new substances, so that option is incorrect.
Burning (combustion) is a chemical change: the wood’s molecules are chemically transformed into ash, carbon dioxide, water vapor, and other products. Mass is conserved overall (law of conservation of mass) in a closed system, though in an open fire gases escape so the remaining solid mass appears reduced. A purely physical change does not produce new substances, so that option is incorrect.
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