Question

which observation best indicates that a chemical change has occurred? a water boils and turns into steam. b ice melts into liquid water. c bubbles form when vinegar is added to baking soda. d salt crystals form after water evaporates

Explanation:

A chemical change results in the formation of new substances. When vinegar (acetic acid) reacts with baking soda (sodium bicarbonate), carbon - dioxide gas is produced, forming bubbles. This indicates a chemical reaction. Options A, B, and D are physical changes where the substance's state changes but no new substances are formed.

Answer:

C. Bubbles form when vinegar is added to baking soda.