Q 11. Calculate the number of aluminium ions present in 0.051 g of aluminium oxide.
Give, the mass of Aluminum Oxide = 0.051 g.
The molecular mass of Aluminium Oxide = 2 x mass of Aluminium + 3 x mass of Oxygen.
= 2 x 27 + 3 x 16
= 102 g
Number of Moles of Aluminium Oxide :
Now, Since 1 mole of Aluminium Oxide contain 2 moles of Aluminium ion,
The Number of Moles of Aluminium ion = 2 x number of moles of Aluminium Oxide
= 2 x 0.0005
= 0.001 moles.
Now, As the number of ion in 1 mole = ions.
The number of ions in 0.001 moles of Aluminium ion = ions
= ions.
Hence there are Aluminium ions in 0.051 g of aluminium oxide.