Molecular formula mass and molecular concept definition and numerical

 

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