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MOLE

MOLE 
  1. The relative atomic mass of an element, the relative molecular mass of a molecule, the relative formula mass of an ionic substance or ionic mass of ionic specie when expressed in grams is called gram mole or simply mole.
  2. One mole of a substance is the amount in grams which contains 6.02×1023 particles of that substance.
  • It is denoted by “n”.
  • It is abbreviated as “mol”.
  • It is the  basic SI unit of measuring the quantity of substance.
Example:
(i)  Element                                Na       =          23g      = 1mole
(ii) Molecular compound        H2O     =          18g      = 1mole
(iii) Ionic compound               NaCl      =          58.5g   = 1mole
(iv) Ionic specie                       HCO-3    =          61g      = 1mole
(i) Gram atom (mole):
The relative atomic mass of an element when expressed in grams is called gram atom it is also called 1mole.
Example:
1gram atom (1mole) of Na = 23g
1gram atom (1mole) of Cl = 35.5g
Number of gram atoms or moles of an element =
(ii) Gram molecule (mole):
The relative molecular mass of a molecule when expressed in grams is called gram molecule. It is also called 1mole.
Example:
1gram molecule (1mole) of water = 18 g of H2O
1gram molecule (1mole) of sulphuric acid = 98 g of H2SO4

(iii) Gram formula (mole):
The relative formula mass of a formula unit when expressed in grams, is called gram formula. It is also called 1mole.
Example:
1gram formula (1mole) of NaCl     = 58.5 g
1gram formula (1mole) of Na2CO3 = 106 g
(iv) Gram ion (mole):
The ionic mass of an ionic specie when expressed in grams, is called gram ion or one mole of ion. It is also called 1mole.
Example:
1gram ion (1mole) of OH-  = 17g
1gram ion (1mole) of SO42–= 96 g
Number of gram ions or moles of an ionic specie = 

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