0Mole Concept
Ostwald suggested the term “mole” means heap in Latin.
A mole is defined as the amount of substance which contains the exact same number of elementary particles (i.e. atoms, molecules or ions) as the number of atoms present in 12 g of C-12 isotopes of Carbon.
The SI unit of mole i.e. amount of matter is mol.
1 mol atoms = 6.023 * 10^23 atoms = one gram-atom = gram atomic mass
1 mol ions= 6.023 * 10^23 ions= one gram-ion= gram ion mass
1 mol molecules= 6.023 * 10^23 molecules = gram molecular mass
In gaseous state at STP (T = 273 K, p = 1 atm), Gram molecular mass = 1 mol = 22.4 L = 22400 cc =6.022 * 10^23 molecules
Standard number 6.022x 10^23 is called Avogadro number in honour of Avogadro and is denoted by NA.
The volume occupied by one-mole molecules of a gaseous substance is called molar volume or gram molecular volume.
Number of moles = amount of substance (in gram) / molar mass
Number of molecule = number of moles * NA
Number of molecules in Ig compound = NA / g-molar mass
Loschmidt number: Number of molecules in 1 cc or cm3 (1 mL) of an ideal gas at STP is called Loschmidt number (2.69x 10^19).
[One amu or u (unified mass) is equal to exactly the 1 / 12th of the mass of C-12 atom, i.e., 1 amu or u = 1 / 12 * mass of one carbon (C12) atom
1 amu = 1 / NA= 1 Dalton = 1/ (6.022x10^23)=1.66x 10-24 g
One mole of electrons weighs 0.55 mg (5.5x 10-4 g).
