your answer is <u>D</u><u>.</u><u> </u>physical change, because a new substance is not formed.
1) 1 molecules
2) 2 oxygen atoms
3)2 moles of Al2O3 are formed
4)4:3
Isotopes are two atoms with the same number of protons, but a different number of neutrons. Because they have the same number of proton they are atoms of the same element, but with different masses.
so, the answer is c.
i hope this will help you
