Answer:
13.4%
Explanation:
Take the molar mass (26.98) of Al x 2 because there are 2 moles in the given compound. Divide this number by the total molar mass of the compound (401.9) this gives you .134. To get a percentage mulitply by 100 for 13.4%.
[(26.98 x 2)/401.9] x 100 =13.4
