Calculate the number of moles in the following masses

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

(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