Question

Number of atoms in 85u of NH3

Answer 1

Your answer is ---

molecular mass of NH3 = 14+1×3 = 17u

So, moles of NH3 = 85/17 mol = 5mol

Number of molecules = 5 × NA (Avogadro number )

= 5 × NA = 5×6.023×10^23

= 30.115 × 10^23 molecules

Now, NH3 contain
3hydrogen atom and 1 nitrogen atom. total 4 atom .

so,number of atom =

4 × 30.115 × 10^23

= 120.46 × 10^23 atoms

【 Hope it helps you 】

Answer 2

molecular weight of NH3=17 amu
given molar weight=85amu
so no of moles=85/1=5moles
no of H atoms in one mole=3
so no of H aoms in  moles=3*5=15 atoms
hope this will help you