Question

Calculate the number of molecules in 8.5 gm Ammonia (atomic mass of H=1u,N=14u)

Answer 1

Hi.

Here is your answer----

Mass of Ammonia (NH3) = 8.5 grams.
Molecular mass of Ammonia(NH3) = 17 grams

Using formula,
          Number of molecules = (Mass/molecular mass) x  Avogadro's number
                                            = (8.5/17) x 6.022 x 10^23
                                            = 3.011 x 10^23

Thus, number of molecules in 8.5 grams of Ammonia is 3.011 x 10^23


Hope it helps.

Have a nice day.