a. How many atoms of hydrogen are in 25.0 g of ammonia (NH3)? Use the format 6.02E+23 for 6.02 x 1023

b. How many atoms of nitrogen are in the same amount of ammonia?

2 answers

How many moles in 25.0 g NH3?
moles = grams/molar mass.
There are 6.02E23 molecules in 1 mole of NH3 and there are 3 H atoms per molecule. Therefore,
6.02E23 x (25.0/molar mass) x (3 atoms H/molecule NH3) = ??

b is done the same way but there is only 1 N atom per molecule NH3.
26.572E1023