Question

How many electrons are present in 1.6 g methane?

Answer 1

No. of moles of methane = 1.6 / 16 = 0.1 

No. of molecules of methane = 0.1 x N_A 

No. of electrons in one molecule = 6 + 4 x 1 = 10 

∴ No. of electrons on 1.6 g methane = 0.1 x N_A x 10 = N_A