How many moles is 1.50x10^23 molecules of nh3?

 The   number  of moles that are  1.50  x10^23  molecules of NH3  are  

 =0.249 moles

        calculation

 The number of  moles is calculated  using  Avogadro's  law  constant

that  is  According  to Avogadro's  law

                         1  moles  of a  substance = 6.02 x10^23  molecules

                                    ?    moles                =  1.50  x10^23  molecules

by  cross  multiplication

= [( 1.50  x 10^23  molecules  x  1 moles) / (6.02 x10^23)]  = 0.249  moles

the formula mass of a molecule or a compound is the sum of the atomic weights of the atoms in its empirical formula

(that's what i know about formula mass)

points

explanation: