Question

How many atoms are present in 2.24L of NH3 at STP?

Answer 1

No of moles=given volume/volume at STP

No of moles= 2.24/22.4= 0.1

No of atoms= atomicity of nh3 × no of moles× Avogadro's no

= 4×0.1× 6.022×10^23

= 24.088×10^22

Answer 2

We know,

1 ml =1/2240 moles (At STP)

and,

1 mole = 6.022 x 1023 molecules

So, number of molecules of ammonia in

1 ml = 6.022 x 1023/2240. -------(1)

Now,

Multiply eq. (1) by 4,

6.022 × 1023/2240 × 4 = 11

So, 11 atoms are there in 2.24 L of NH3 at STP.