example
•
18.94 g Al reacts with O to make 35.74
g
aluminum oxide. what is the empirical
formula?
(note: where is g O?)
•
18.94 g Al
è
0.701 mol Al
•
16.80 g O
è
1.05 mol O
•
0.701 / 0.701 = 1 Al
•
1.05 / 0.701 = 1.5 O
•
This is a
2:3
ratio, therefore
Al
2
O
3