The chemical equation shows how ammonia reacts with sulfuric acid to produce ammonium sulfate.

2nh3(aq) + h2so4(aq) mc012-1.jpg (nh4)2so4(aq)

how many grams of ammonium sulfate can be produced if 60.0 mol of sulfuric acid react with an excess of ammonia?

The balanced chemical reaction is:

2NH3(aq) + H2SO4(aq) = (NH4)2SO4(aq)

We are given the amount of sulfuric acid to be used for the reaction. This will be the starting point of our calculations.

60.0 mol H2SO4 ( 1 mol (NH4)2SO4 / 1 mol H2SO4 ) ( 132.14 g (NH4)2SO4 / 1 mol (NH4)2SO4 ) = 7928.4 g (NH4)2SO4

Aquantity of that isotope to decay to 1/2 of  its original value

Ithink it's the third answer