Molecular formula mass and molecular concept definition and numerical

Asked by Esha Gupta | 21st Mar, 2017, 03:14: PM

Expert Answer:

The formula mass of a molecule is the sum of the atomic masses of the atoms in the empirical formula of the compound.

Mole Concept

A mole is a collection of 6.022 × 1023 particles.

A mole is defined as the amount of a substance containing elementary particles like atoms, molecules or ions in 12 gram of carbon-12 (12C).


Important Formulae for Numericals:

Relative molecular mass of a gas or vapour = 2 × VD

Mole and Gram Atomic Mass: One mole of atoms = 6.022 ×1023 atoms

                                                                                = Gram atomic mass of an element

                                                                                = 1 gram atom of the element


Mole and Gram Molecular Mass: One mole of molecules = 6.022 ×1023 molecules

                                                                                           = Gram molecular mass

                                                                                           = 1 gram molecule of the compound


Mole in terms of volume:               One mole of a gas        = 22.4 litres at S.T.P.


Moles of an element = Mass of the element

                                   Atomic mass or GA.W


Moles of a compound = Mass of the compound

                                     Molecular mass or GMW


Mass of one atom = Atomic Mass or GAW

                                      6.022 × 1023


Mass of one molecule = Molecular Mass or GAW

                                             6.022 × 1023


Number of molecules = Moles × 6.022 ×1023


Number of atoms = Moles × 6.022 ×1023



Answered by Vaibhav Chavan | 21st Mar, 2017, 05:41: PM