Question

How many molecules (not moles) of NH3 are produced from 3.06×10−4 g of H2?

Answer 1

The reaction you are talking about must be

N2 + 3H2 --> 2NH3

So as per stoichiometry of above reaction , 2 moles of NH3 will be produced by 3 moles of H2

the moles of H2 used here = Mass of H2 / Molecular weight of H2 = 3.06 X 10^-4 / 2 = 1.53 X 10^-4 moles

so moles of NH3 produced will be = 2 X 1.53 X 10^-4 moles / 3 = 1.02 X 10^-4 moles

Molecules of NH3 produced = moles X avagadro number of molecules = 1.02 X 10^-4 X 6.023 X 10^23 molecules

Molecules of NH3 = 6.143 X 10^19 molecules