Question

Calculate no. Of atoms in 8 g
of Oxygen(O2) molecules

Answer 1

Number of moles of O2=given weight(m)/molar mass of O2(M)

Molar mass of O=16
so, molar mass of O2=2*16=32

n=8/32=1/4

No of molecules=no of moles*Avagadro's No.

=1/4*6.022*10^23.=1.5055*10^23. (Answer)

( Since Avagadro's no=6.022*10^23)

Answer 2

no of moles=8/32

                 =0.25 moles

therefore no of atoms=0.25 x 6.022 x 10^23

                                    =1.5055 x 10^23 atoms