1 mole of H²SO = 98g

So... therefore ,

0.25 mole of H²SO = 98/0.25

= 24.5 g

First, find the molar mass of H2SO4 by adding up the molar masses of each individual element. The total is 98.08 grams, so a mole of H2SO4 has a mass of that much. 0.25 moles of H2SO4 would therefore have a mass of a quarter of 98.08, or 24.52 grams.