Question

How are no. molecules of a substance related to its no. of moles??

Answer 1

1 mole = 6.023 x 10 to the power 23 atoms/molecules

Answer 2

Mole is a unit of numbers just like dozen
As 1 dozen = 12, 
1 mole = 6.023 × 10 ²³ (This no. is known as Avogadro's no. or Avogadro's constant)
1 mole of anything ( like bananas, pencils, cars, atoms, etc.) = 6.023 × 10 ²³ 

No. of moles of molecules of a substance 
= No. of molecules / 6.023 × 10 ²³
OR
=  weight of substance ( in grams) / molecular weight