Question

what are the four main indicators of a chemical change? a state-of-matter change, gas production, energy exchange, precipitate b shape change, energy exchange, state-of-matter change, gas production c precipitate, energy exchange, shape change, color change d precipitate, energy exchange, color change, gas production

Explanation:

To determine the correct answer, we analyze the indicators of a chemical change. Chemical changes involve the formation of new substances, and their indicators include the production of a precipitate, energy exchange (like heat or light), color change, and gas production. State - of - matter change (e.g., melting ice) and shape change (e.g., bending a wire) are physical changes, not indicators of chemical changes.

• Option A: State - of - matter change is a physical change indicator, so A is incorrect.
• Option B: Shape change and state - of - matter change are physical change indicators, so B is incorrect.
• Option C: Shape change is a physical change indicator, so C is incorrect.
• Option D: Precipitate, energy exchange, color change, and gas production are all valid indicators of a chemical change.

Answer:

D. Precipitate, energy exchange, color change, gas production