Question

Which of the following is a clue of a chemical change?

A. iron changes color when heated
B. gas bubbles form in boiling water
C. balls of wax form when melted wax is poured into ice water
D. a gas forms when vinegar and baking soda are mixed

Answer 1

The answer is D. a gas forms when vinegar and baking soda are mixed.

Answer 2

D.
A is light energy
B is change of state
C is also change of state
D is only one where atoms are rearranged into new chemicals