# How to use Moles Formula 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 Na_{2}O = (23×2)+16 = 62 ,

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

Ar( relative atomic mass) of O= 16

so moles of 100 g Na_{2}O= 100/ 62= 1.61 moles

### Use of Moles Formula

Calculate number of moles in 50 g of Na_{2}O

Calculate number of moles in 100 g of H_{2}O

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 Li_{2}O

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 MgCl_{2}

Calculate number of moles in 77 g of P_{4}O_{10}

Calculate number of moles in 43 g of H_{3}PO_{4}

Calculate number of moles in 94 g of Cl_{2}O_{7}

Calculate number of moles in 69 g of HClO_{4}

Calculate number of moles in 86 g of SO_{2}

Calculate number of moles in 39 g of H_{2}SO_{3}

Calculate number of moles in 68 g of SiO_{2}

Calculate number of moles in 74 g of Al_{2}O_{3}

Calculate number of moles in 116 g of H_{2}SO_{4}

Calculate number of moles in 5k g of Al_{2}(SO_{4})_{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 CO_{2}

Calculate number of moles in 56 g of N_{2}

Calculate number of moles in 235 g of ??_{4}

Calculate number of moles in 64 g of ?_{2}

Calculate number of moles in 45 g of ?_{6}?_{12}?_{6}

Calculate number of moles in 99 g of ????_{2}

Calculate number of moles in 235 g of ????_{3.}

Read Moles to grams