Question

How many atoms of hydrogen are present in 7.63 g of ammonia? please help me ??

Answer 1

The atoms  of  hydrogen  that are  present  in  7.63 g  of ammonia(NH3)

find  the  moles  of NH3 =mass/molar mass
 7.63 g/ 17 g/mol = 0.449  moles

since there  is  3 atoms of H  in NH3 the  moles of  H = 0.449 x 3 = 1.347 moles

by  use  of  1 mole = 6.02 x10^23  atoms
what  about  1.347  moles

= 1.347  moles/1   moles  x 6.02 x10^23 atoms = 8.11 x10^23  atoms of Hydrogen