Question

Hannah does an experiment. She has two colorless chemicals that she mixes together in a beaker. Which of the following indicates that a chemical change occurs when she mixes the two chemicals together?
I. The chemicals change color from colorless to purple.
II. A yellow gas forms.
III. A brown solid forms in the bottom of the beaker.
IV. The temperature of the chemicals rises 15°C.

Answer 1

I am not to sure but is it all 4 of them?

Answer 2

The answer is all 4 of them