Calculate the number of moles in the following masses

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conceptsofchemistry

#1

Calculate the number of moles in the following masses
(i) 1.46 metric ton of Al (ii) 7.9 mg of Ca


#2

(i) 1.46 metric ton of Al =1.46 x ${{10}^{3}}$ x ${{10}^{3}}$ g of Al
= 1.46x ${{10}^{6}}$ g
Atomic mass of Al = 27
mass of Al / atomic mass = 1.46 x ${{10}^{6}}$ / 27
= 5.41 x ${{10}^{4}}$ mol
(ii) 7.9 mg of Ca= 7.9 X${{10}^{-3}}$ g of Ca
Atomic mass of Ca = 40.1

Moles or Ca = = mass of Ca /atomic mass = 7.9 x${{10}^{-3}}$ / 40.1
= 1.97 X ${{10}^{-4}}$ mol