Find the how many moles of atoms are there in :
(i) 2 g of nitrogen
(ii) 23 g of sodium
(iii) 40 g of calcium
(iv) 1.4 g of lithium
(v) 32 g of sulphur

Explanation

(i) 2g of nitrogen
`"Number of moles"=("Mass")/("atomic mass")`
`"Atomic mass of Nitrogen"=14," Mass of Nitrogen"=2g`
`therefore " Number of moles "=(2)/(14)="0.142 moles of Nitrogen"`
(ii) 23 g of sodium
Atomic mass of sodium = 23
Mass of sodium = 23 g
`"Number of moles"=("Mass")/("atomic mass")=(23)/(23)=1" moles of calcium"`
(iv) 1.4 g of lithium
Atomic mass of lithium = 7
`"Number of moles"=("Mass")/("atomic mass")=(1.4)/(7)`
`=(2)/(1)=0.2" mole of lithium"`
(v ) 32 g of sulphur
Atomic mass of sulphur = 32
Mass of sulphur = 32g
`"Number of moles"=("Mass")/("atomic mass")=(32)/(32)="1 mole of sulphur"`