Question

11.2 L NH3 taken in a cylinder
at STP .
a, find number of gmm of substance?
b, find number of molecules of substance​

Answer 1

We know at S.T.P- 1 mole=22.4L

ammonia is 11.2L, so no of moles of ammonia is 11.2/22.4=0.5moles

a)No of moles=No of gms of substance /Molecular Weight

0.5=No of gm /17(Nh3=14+3 g=17g)

No of gm is=17*0.5=8.5g

b)No of moles=no of molecules/6.022*10^23(Avagadros No)

0.5=no of molecules/6.022*10^23

Therfore no of molecules is 0.5*6.022^23=3.011*10^23

Hope it helps...