Find number of hydrogen atoms:

Question

1 mol of NH3
1 mol of N2H4
4 mol of NH3
3 mol of N2H4

Answer 1

1 mol of any compound (NH3, N2H4, etc) has 6.02E23 molecules. Then NH3 has 3x that many H atoms, N2H4 has 4 x that many H atoms, etc.