Question

How do you calculate the percentage composition of Oxygen in `Zn(NO_3)_2`?

Answer 1

`(6xx15.999*g*mol^-1)/(189.36*g*mol^-1)` `xx` `100%` `=` `??`

Explanation:

`15.999*g*mol^-1` is of course the molar mass of the oxygen atom. `189.36*g*mol^-1` is the molar mass of zinc nitrate. So it is a bit under 50% by mass.

Molar mass of zinc nitrate:
You can calculate this by adding all the atomic masses of the elements in this compound:
`1xxZn+2xxN+6xxO`