What is the mass of 'u' of
(a) 1 mole of nitrogen atoms (b) 4 moles of aluminium atoms
(iii) 10 moles of sodiu sulphate (d) 5 moles of calcium cabronate.
`("Atomic mass of N"=14u, Al=27u, Na=23u, S=32u, O=16u, Ca=40u, C=12u`

Explanation

(a) 1 mole of nitrogen atoms
Mass of 1mole of nitrogen (N)atoms=14u
(b)4 moles of aluminium atoms
Mass of 1 mole of aluminium (Al) atoms=27u
`therefore "Mass of 4 mole of aluminium (Al)atoms"=4xx27=108u`
(c 10 moles of sodium sulphate `(Na_(2)SO_(4))`
`"Molar mass of"Na_(2)SO_(4)=2xx"Atomic mass of Na "+"Aromic mass of S"+4xx"Atomic mass of O"=2xx23+4xx16=46+32+64=142u`
1 mole of sodium sulphate has mass=142u
10 moles of sodium sulphate have mass `=10xx142=1420u`
(d) 5 moles of calcium carbonate `(CaCO_(3))`
Molar mass of `CaCO_(3)="Atomic mass of Ca"+"Atomic mass of C"+3xx"Atomic mass of oxygen"`
`=40+12+3xx16=100u`
1 mole of calcium carbonate has mass =100u
5 moles of calcium carbonate have mass `=5xx100=500u`