MOLE

The chemist defined the mole as Avogadro’s number (6.022 x 10²³) of atoms, molecules, ions, or other species. The number of moles is calculated from:

             

Example 1

How many moles are present in 1.00 g of P4O6

Solution

The formula weight of P4O6
= (4x30.97) + (6x16.00)
= 219.88 g/mol

Mole of P4O6
= 1 / 219.88
 = 4.55 x 10^-3 mol


Example 2

Calculate the mass of 0.050 mol of dimethylnitrosamine (CH3)2N2O ?

Solution

We calculate the formula weight of dimethylnitrosamine, as follow:

= (2x12.01) + (6x1.00) + (2x14.01) + (1x16.00)
= 74.04 g/mol

Mass of (CH3)2N2O

= mol x formula weight
= 0.050 mol x 74.04 g/mol
= 3,702 g