Answer:
Aluminium oxide has the formula Al2O3. This has a formula mass of 101.96 g mol−1.
That means that 12 g of Al2O3 contain 12 g / 101.96 g mol−1 = 0.118 moles of Al2O3.
Each Al2O3 formula unit contains two Al3+ ions, so there are 2 x 0.118 mol = 0.235 moles of Al3+ ions.
If you want an actual number, you can multiply that by Avogadro’s constant: 0.235 mol x 6.022 x 1023 mol−1 = 1.42 x 10 23 ions.
Explanation:
