Question

The number of molecules in 4.25 gram of ammonia approximately is

Answer 1

Molar mass of NH3 = 14+3= 17g/mol
mass given= 4.25g
so, number of moles = 4.25/17 = 0.25mol of NH3

1 mol of NH3 has 6.022 x $10^{23}$ molecules

0.25 moles of NH3 contains 0.25 x 6.022 x $10^{23}$ molecules
= 1.5055 x $10^{23}$  molecules

Answer 2

$\Huge\purple{\mathfrak{\underline{\underline{Solution}}}}$

→ Molar mass NH3 = 14+3 = 17g/mol

→ 4.25g = 4.25/17 = 0.25 mol NH3

→ 1mol = 6.022× 10²³ molecules

→ 0.25 mol = 0.25×6.022×10²³

→ Number of molecules = 1.51×10²³ molecules NH3.