Practice Test 4

The vinegar molecules melted, creating bubbles, and melting always makes the temperature drop.

The cup became cooler first, and that caused the particles to turn into a gas that makes bubbles.

A chemical reaction rearranged atoms to form new substances, including a gas that forms bubbles, and energy changes made the mixture cooler.

The bubbles are vinegar particles evaporating, and evaporation means atoms rearrange into new molecules.