Question

No. of atoms in 4.25 of NH3 is approx

Answer 1

Molar mass NH3 = 14+3*1 = 17g/mol 
4.25g = 4.25/17 = 0.25 mol of NH3 

1 mol of NH3 contains 6.022*10^23 molecules 
0.25 mol NH3 contains 0.25*6.022*10^23 = 1.5*10^23 molecules 

1molecule of NH3 comtains 4 atoms 
Number of atoms in 1.5*10^23 molecules = 6*10^23 atoms. 

The correct answer is choice C = 6*10^23 atoms.
I hope it helps you if yes then mark it as brainliest

Answer 2

Here is the Sol. hope it will help.