Question

How many electrons are present in 1.6 g of methane ?

Answer 1

Gram-molecular mass of methane =12+4=16g

Number of moles in 1.6g of methane $=\frac{1.6}{16}=0.1$

Number of molecules of methane in 0.1 mole$=0.1\times 6.02\times {10}^{23}=6.02\times {10}^{22}$

One molecule of methane has 6+4=10 electrons

So,

$6.02\times {10}^{23}$ molecules of methane have $10\times 6.02\times {10}^{22}=6.022\times {10}^{23}electrons$