Question

What is the no of molecules in. 25g of nh3

Answer 1

no of molecules = mass of nh3 ÷ Molecular mass of nh3

.: n = m ÷ M
.: n = 25 ÷ 14+1×3
=25 ÷ 14+3
=25÷17
.: n = 1.470
.:No. of molecules in25g of nh3 is 1.470

Answer 2

At STP,
17 gm NH3 -> 1 molecule NH3
25 gm NH3 -> (25×1)/17 = 1.47 = 2 molecule (apprx)