Sulfuric acid dissolves aluminum metal according to the following reaction: 2Al(s)+3H2SO4(aq)--->Al2(SO4)3(aq)+3H2(g) Suppose you wanted to dissolve an aluminum block with a mass of 15.9g.What minimum mass of H2SO4(in grams) would you need?

15.9 grams Al (1 mole Al/26.98 grams)(3 mole H2SO4/2 mole Al)(98.086 grams/1 mole H2SO4)

= 86.7 grams of sulfuric acid minimum

These are just thinking it through problems. You try to get H2 mass and don't forget mole ratios.