Question

Calculate molecules of methane,C and H atoms in 25g methane

Answer 1

Gram molecular mass of methane = 16 g

According to Avogadro's law
The G.M.M of a substance contains 6.02*10^23 molecules

Therefore
16 g of CH4 contains = 6.02*10^23 molecules
1g of methane contains = 60.2*10^23/16 molecules
Therefore
25 g of CH4 contains = 6.02*10^23*25/16
                                     = 9.40625 * 10^23 molecules (approximately)

Hope this helps you.