Which set of procedures and observations indicates a chemical change? a) ethanol is added to an empty beaker and the ethanol eventually disappears. b) a solid is gently heated in a crucible and the solid slowly turns to liquid. c) large crystals are crushed with a mortar and pestle and become powder. d) a cool, shiny metal is added to water in a beaker and rapid bubbling occurs.

The correct answer is D. A cool, shiny metal is added to water in a beaker and rapid bubbling occurs.

Explanation:

In chemistry, the matter can undergo two main changes: physical change and chemical change. A physical change occurs as there is a change in the state but not the properties, for example, a solid becomes a liquid or a liquid becomes a gas. On the other hand, a chemical change involves a change in composition; this can be identified due to the formation of bubbles or major changes such as a difference in color or odor. According to this, the option that indicates a chemical change is "A cool, shiny metal is added to water in a beaker and rapid bubbling occurs" because in this case there is a formation of bubbles that indicates the composition of the substances has change and therefore a chemical change occurred.

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