# Moles Formula for calculations

How to use Moles Formula for calculations for a substance?

Practice questions/worksheet

Use the following Moles Formula

Mole(n)= Mass of a substance(m)/ Molar mass(Mr)

so moles of a substance , n= m / Mr

The first question is solved for you.

For calculating Molar mass, you need to add the relative atomic masses of all the atoms in a

compound or ion. For example Mr of Na2O = (23×2)+16 = 62 ,

because  Ar( relative atomic mass) of Na=23,

Ar( relative atomic mass) of O= 16

so  moles of 100 g Na2O= 100/ 62= 1.61 moles

### Use of Moles Formula

Calculate number of moles in 50 g of Na2O

Calculate number of moles in 100 g of H2O

Calculate number of moles in 25 g of NaOH

Calculate number of moles in 75 g of MgO

Calculate number of moles in 65 g of Mg(OH)2

Calculate number of moles in 15 g of Li2O

Calculate number of moles in 85 g of HCl

Calculate number of moles in 33 g of LiCl

Calculate number of moles in 48 g of MgCl2

Calculate number of moles in 77 g of P4O10

Calculate number of moles in 43 g of H3PO4

Calculate number of moles in 94 g of Cl2O7

Calculate number of moles in 69 g of HClO4

Calculate number of moles in 86 g of SO2

Calculate number of moles in 39 g of H2SO3

Calculate number of moles in 68 g of SiO2

Calculate number of moles in 74 g of Al2O3

Calculate number of moles in 116 g of H2SO4

Calculate number of moles in 5k g of Al2(SO4)3

Calculate number of moles in 2.5 g of CO

Calculate number of moles in 10 g of NO

Calculate number of moles in 88 g of CO2

Calculate number of moles in 56 g of N2

Calculate number of moles in 235 g of NH4

Calculate number of moles in 64 g of F2

Calculate number of moles in 45 g of Sucrose?

Calculate number of moles in 99 g of Fe

Calculate number of moles in 235 g of NH3.