Which of the following observations is the most definitive evidence that a chemical change has taken place?

Which of the following observations is the most definitive evidence that a chemical change has taken place?
  1. A change in state from liquid to gas
  2. Formation of a new substance with totally different properties
  3. A change in size or shape of the material
  4. A temporary change in temperature

Solution

The creation of one or more entirely new substances with distinct chemical properties is the key identifier of a chemical change.

Asked in: Homi Bhabha Practice

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