Question

find the no of aluminium ions present in 0.o501 g of aluminium oxide​

Answer 1

Molecular weight of Al2O3 = 102 g

102 g of Al2O3 contains 6.022X1023 molecules

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

3 X 1020 molecules contains – 2 X 3 X 1020

= 6 X 1020 Al+3 ions ∴0.051 g of Al2O3 contains 6 X 1020 Al+3 ions

Answer 2

1. Molecular weight of Al2O3 = 102 g.
2. 102 g of Al2O3 contains 6.022X1023 molecules.
3. 0.051g of Al2O3 contain X number of molecules.
4. X = 0.051 X 6.022X1023 /102 = 0.003 X 1020
5. X = 3 X 1020
6. 1 molecule of Al2O3 contains – 2 Al+3ions.