Question

10gm CH4 contains how many neutrons

Answer 1

Firstly we calculate number of moles
So,

n=10/16 = 0.625

now
    no. of atoms in each mole = 6.022 x 10^23
∴  no. of atoms in 0.625 = 6.022 x 10^23 x 0.625
                                       = 3.7637 x 10^23

Now no. of neutrons will only account for C because H doesn't contain any neutron

No. of neutrons in a C atom = 6

No. of neutrons in 3.7637 x 10^23 C atom = 6 x(3.7637 x 10^23)
                                                                 => 22.5822 x 10^23 neutrons

That's all