# Too much leftover in zinc sulfate reaction?

I'm doing a reaction of zinc metal and sulfuric acid to get zinc sulfate. I've been trying to learn the chemistry lately so I tried to measure out correct molar amounts. My understanding from the equation is that it's equimolar:

Zn + H2SO4 = ZnSO4 + H2

Sulfuric acid has a molar mass of 98.079 g/mol and zinc metal is 65.38 g/mol. The density of sulfuric acid is 1.84 g/ml (yeah cubic centimeter but it's a ml), 98.079 / 1.84 = 53.3 ml/mol. I believe my acid to be about 96%-ish, so to give myself a fudge factor I measure out 60ml of acid, diluted with 120ml of water. I put in about 65 grams of zinc metal (over time). When the bubbling had mostly stopped I had a pretty much solid mangle of zinc metal at the bottom of the jar, and even some air bubbles trapped underneath where the liquid couldn't get to anymore. There was also a white precipitate.

I'm confused why my (mostly) equimolar amounts left SO much zinc after, far more than even 10 or so grams.

Edit: I filtered the liquid still left in the jar through coffee filters. Cheap ones, but I layered them and stuffed one into the stem. It took a long time to filter, and is black...I also added more distilled water and some 35% acid to dissolve the rest of the zinc in the jar. It's bubbling away happily now.

Remember the activity coefficient of $$\ce{H+}$$ raises very fast with acid concentration, so e.g. 10 times diluted acid reacts much slower than 10 times.