what mass of H2SO4 is contained in 25g of 15percent w/w solution?

Answer 1

% w/w = (grams H2SO4/1 g solution)*100.
15 = (grams H2SO4/25)*100
Solve for g H2SO4.

Answer 2

Mass of h2so4=1×2+32+16×4.
=98g
Mass of h2so4=25g/98g=0.26g
0.26×15/100
=0.038g