Which of the following would indicate the formation of a new substance?

• A. The substance is dissolved in water.
• B. The temperature of the substance is increased by heating.
• C. A color change occurs during a reaction.
• D. The substance is crushed into smaller pieces.

Answer: (C)

Verified step by step guidance

1. Understand that the formation of a new substance is a chemical change, which involves making or breaking chemical bonds, resulting in different chemical properties.
2. Recognize that physical changes, such as dissolving in water, heating (temperature increase), or crushing into smaller pieces, do not create new substances but only change the physical state or form.
3. Identify that a color change during a reaction often indicates a chemical change because it suggests that the molecular structure and properties of the substance have changed.
4. Recall that chemical changes are usually accompanied by other signs such as gas production, precipitate formation, or energy changes, but color change is a common and clear indicator.
5. Conclude that among the options, the color change during a reaction best indicates the formation of a new substance.