You're off to a good start, now find the mass of H2O and put it under I mol,
then multiply 1 mol over the mass of H2O by 215 grams
I think B. As an idea is just a way that could be possible
Molecule is the general term used to describe any atoms that are connected by chemical bonds. Every combination of atoms is a molecule. A compound is a molecule made of atoms from different elements. All compounds are molecules, but not all molecules are compounds.
One example of a molecule is 
(chlorine).
Examples of a compound is NaCl (sodium chloride) or 
(water)
What are the variables you have? I can't answer if I don't know? Haha. :)
Mass =70 ( Mass of protons=1 ,Mass of neutrons =1, Mass of electron =0.0005(can be ignored))
Therefore, 40 +30=70
Charge= -2 ( it is taking in/attracting electrons to its shell) base on the proton number you are able to identify if it is attracting or releasing an electron, if the electron number is more than proton number then it is attracting therefore resulting in a negative charge vice versa for releasing an electron.
