Question

3. What is the main difference between a physical change and a chemical
change?
A. Physical changes alter the composition whereas chemical changes alter the
appearance of a substance.
B. Physical changes describe the appearance of a substance whereas chemical
changes describe qualities only observed with a reaction.
C. Physical changes describe qualities only observed with a reaction whereas
chemical changes describe the appearance of a substance.
D. Physical changes alter the appearance whereas chemical changes alter the
composition of a substance,

Answer 1

Answer:

B and D could both be right as they are quit similar.

Consider two rods of the same length and diameter,

Increasing the diameter of one would change the expansion qualities of that rod even though there would be no chemical changes,

However, leaving the physical appearance of both rods the same while applying a reactive substance (acid or something) to one of the rods would not necessarily change the physical appearance of that rod but could make a considerable change in the  physical properties of that rod.