Answer:
those are all physical changes and most physical changes can be undone like crushing a pice of metal you can flatten it back out you anwser is physical change
Explanation:
Answer is: formula is Al₂(CO₃)₃.
Aluminium carbonate (Al₂(CO₃)₃) has neutral charge. Because aluminium cation has positive charge 3+ and carbonate anion has negative charge 2-, for right chemical formula, we need two aluminium cations and three carbonate anion:
charge of the molecule = 2 · (3+) + 3 · (-2).
charge of the molecule = 0.
Answer:
See below
Explanation:
Ammonium 
is not a molecular ion because it is just a poly-atomic ion. A molecular ion has a "negative or positive charge" as a whole but the positive charge on here is not on the whole. So, it is a poly-atomic ion and not molecular ion.
Answer is D breaking apart I to not more than two
