If 36 grams of aluminum react with an excess of oxygen, as shown in the balanced chemical equation below, how many grams of aluminum oxide can be formed? (1 point)

4Al + 3O2yields 2Al2O3

68 grams
24 grams
272 grams
18 grams

Answer :

molar mass of Al = 26.98
molar mass of Al2O3 = 101.96
36 / 26.98 = 1.3343 moles Al 
set up a proportion : 1.3343 / 4 = x / 2 (let x = moles of Al2O3) 
x = 0.66716 moles of Al2O3
0.66716 * 101.96 = 69.024 g of Al2O3 

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