Question

physical and chemical changes - 7.6c
4 an experiment was performed in which a crystalline substance was added to a beaker filled with a liquid at room temperature. the observations made during the experiment were as follows.

1. the crystals dissolved
2. a precipitate formed
3. the bottom of the beaker felt warm to the touch
4. bubbles formed in the water

all of the observations are evidence that a chemical change occurred except-
a observation 1
b observation 2
c observation 3
d observation 4

Explanation:

A chemical change results in the formation of new substances. Precipitate formation, heat - release (beaker feeling warm), and bubble formation usually indicate new substances are formed. Dissolving is a physical change where the substance just disperses in the solvent without forming a new substance.

Answer:

A. observation 1