Question

Can someone answer all 3 questions plz?

Answer 1

Question one should be obvious..

Mass can't be created not destroyed no matter what, so even in a chemical reaction, the answer will remain. The first answer is correct.

Question two

No, because even when water is broken down, there should only be one molecule of oxygen. The fact there is two means it's incorrect.

Question three

Yes. The equation is perfectly balanced on both sides, so it's safe to say the value of mass remains constant.