The total number of units in one mole of any substance is called Avogadro’s number or Avogadro’s constant. It is equal to 6.022140857×1023 and this number is really a huge. In the below mentioned pdf we have given lot of examples to give you brief idea about how big one mole is. And the units may be electrons, ions, atoms, or molecules, depending on the character of the reaction and the nature of the substance. For More Chemistry Formulas check out Main page of Physics Wallah.
Equal volumes of all gases under similar conditions of temperature and pressure contains equal number of molecules.
Find below Pdf of Avogadro's Number