Question

A cylinder contains $68g$ of ammonia gas at STP.
How many molecules of ammonia are present in the cylinder? $[N-14,H-1]$

Answer 1

One mole of $N{H}_3$ contains = $6.022\times {10}^{23}$ molecules.

$\therefore$ 4 moles of $N{H}_3$ contains = $4\times 6.022\times {10}^{23}$

= $2.4088\times {10}^{24}$ molecules.