Question

Why physical and chemical changes needed to be classified

Answer 1

Explanation:

physical and chemical changes needed to be classified to see whether change is occured or not.

Answer 2

Explanation:

Look for an indication that a chemical change occurred. Chemical reactions release or absorb heat or other energy or may produce a gas, odor, color or sound. If you don't see any of these indications, a physical change likely occurred. Be aware a physical change may produce a dramatic change in the appearance of a substance.