posted by mike .
did you read my previous post? I just want to mke sure understand what the answer is I think it's 1.11
No, the answer is 2.22 grams.
1.11 is the number of mols H2 which you calculated correctly. Then you converted 1.11 mols to grams by
1.11 mols H2 x molar mass H2 = 1.11 mols x 2 g/mol = 2.22 grams H2 produced by 20 g Al. You did that correctly, also. The ONLY thing you didn't do is to show that Al was the limiting reagent and not H2SO4 (since both a quantity of Al AND a quantity of H2SO4 were given.)
ok thank you very much for your help