Question

Calculate the number of al3 ions in 0.056 g of al2 o3

Answer 1

Molecular weight of Al2O3 = 102 g.
102 g of Al2O3 contains6=.022X1023molecules.
0.051g of Al2O3 contain X number of molecules
X = 0.051 X 6.022X1023 /102 = 0.003 X 1020

X = 3 X 1020

1 molecule of Al2O3 contains – 2 Al+3ions.

Answer 2

Molar mass Al2O3 = 102 g / Mol
Moles Al2O3 = 0.056 / 102 = 0.000549
Moles Al3+ = 0.000549 x 2 = 0.00110
Number of Al3+ ions = 0.00110 x 6.02 x10^23 = 6.6 x 10^20