Pure magnesium's formula would just be Mg because all elements except for 7 nonmetals are just left alone when they are by themselves in a formula. The 7 diatomic elements( means they have to have two of them without another element attached to it aka. a subscript two after it when it's by itself) are hydrogen, nitrogen, oxygen, fluorine, chlorine, bromine, and iodine. An easy way to remember the diatomic seven is that when looking at a periodic table if you trace over them from nitrogen over to fluorine and down to iodine all of those elements are diatomic + hydrogen.
And your unbalanced and balanced equations are correct.
(sorry I went on a tangent with the diatomic rules hopefully it will help you in the future though)
Explanation:
32
2H
2
+O
2
→2H
2
O
Molecular mass of H
2
=2 g/mol
Molecular mass of O
2
=32 g/mol
From the balanced chemical equation,
2×2=4 g of hydrogen requires 32 g of Oxygen to react completely
The answer is predict, because it fits, and because someone can predict the outcome of something.
A and b are related because if u look carefully at what its showing u that there both the same but what its telling u is not the same.
a and c are the same but the picture is different and also the way they describe it is different and what they want u to look at is that if you look at it closely then youll know the difference and how to find it as well