Question

Which of these never changes during a chemical change?

a. the arranhement of the atoms
b. the total number of molecules
c. the total number of atoms
d. the color of the reactants

Answer 1

B is not correct because new molecules are formed so numbers can change. D isn't correct because the color often changes, for example metallic iron and clear oxygen form red rust. The arrangement of the atoms changes, too so a isn't correct. C is cotrect