First, we need to find the values of molar mass of Al and O at the periodic table:
Al : 27 g/mol
O: 16 g/mol
Now let's calculate the molar mass of Al2O3:
(2x27) + (16x3)
54 + 48 = 102 g/mol
Now let's calculate the percent of each element:
For Al:
102 ---- 100%
54 ---- x%
x = 52.9%
For O:
102 ---- 100%
48 ---- y%
y = 47.1%
Answer: 52.9% Al, 47.1% O