Should be 33. but I habe no clue
There are 18. In each molecule of Fe(NO3)2 there are 6 oxygen atoms because you have 2 nitrate (NO3) components which each contain 3 oxygen atoms. 2 x 3 = 6. Because you have 3 molecules of Fe(NO3)2, you need to multiply 6 by 3, which gives you 18 oxygen atoms.
By Boyles Law (P1V1=P2V2), substituting values in and solving for V2, we find that the new volume is 3.6 L<span />
