1) Find the formula mass of Al2O3.
Aluminum mass: 26.982 u.
Oxygen mass: 15.999 u.
Al2O3 mass = 2 * (26.982 u) + 3 * (15.999 u)
Al2O3 mass = 101.961 u.
2) Aluminum percentage.
Aluminum mass: 26.982 u.
Al2O3 mass = 101.961 u.
[tex]\frac{(2*26.982\text{ }u)}{101.961\text{ }u}=0.5293[/tex]Moving the decimal point.
52.93%
The percentage of aluminum is 52.93%
3) Oxygen percentage.
Oxygen mass: 15.999 u.
Al2O3 mass = 101.961 u.
[tex]\frac{(3*15.999\text{ }u)}{101.961\text{ }u}=0.4707[/tex]Moving the decimal point.
47.07%
The percentage of oxygen is 47.07%.
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