Answer:
Tha nolar mass of aluminium is 26.98 g/mol; the molar mass of (atomic) oxygen is 16.90 g/mol.
Explanation:
1 mol of Al2O3 therefore has a mass of 2(26.98)+3(16.00)=101.96 g.
Divide this into the given mass, to find the number of moles here:
(204 g)/(101.96 g/mol)=2.001 mol
There are 2 moles of aluminium per mole of aluminium oxide, so there are 2(2.001)=4.002 moles of aluminium in the sample.
Then there are (4.002 mol)(26.98 g/mol)=107.97 g of Al. Since the given mass has only 3 significant figures, round this answer o 108 g.
