Calculate the number of aluminium ions present in 0.051 g of aluminium oxide. (Hint: The mass of an ion is the same as that of an atom of the same element. Atomic mass of Al = 27 u)
Molar mass of Al2O3=2× mass of O=2×27+3×16=102g 1 mole of Al2O3 contains 2 moles of Aluminium ions So, 102 g of Al2O3 contains 2×6.022×1023 Aluminium ions Hence,0.051 g of Al2O3 will contain =1022×6.022×1023×0.051 Aluminium ions =6.022×1020 Aluminium ions
