Question

What is the mass of aluminium in 204 g of aluminium oxide? Options 1 102 g 2 27 g 3 54 g 4 108 g

Answer 1

The molar mass of aluminium is 26.98 g/mol; the molar mass of (atomic) oxygen is 16.00 g/mol.

1 mole 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 to 108 g.

Answer 2

Answer:

mass of aluminium in 204 g of aluminium oxide

Explanation:

is 108 g