i need some help understanding this problem please.

How many moles of O are there in 32.4g N2O5, how many oxygen and nitrogen atoms are there in the 32.4g?

3 answers

N2 = 28 g/mol
5O =5*16 = 80 g/mol
so N2O5 = 108 g/mol

32.4 g * 1 mol/108 g = .3 moles of N2O5
that is 5*.3 = 1.5 moles of O
1.5 * 6*10^23 = 9*10^23 atoms of O

.6 moles of N
.6*6*10^23 = 3.6*10^23 N atoms
1.5x6.02x10^23=9.03x10^23 (3 sig. figs. as in 32.4) is the correct answer.
1.5 molN2O5
Express your answer using two significant figures.