Concentration of solution help?

Question

A concentrated sulphuric acid solution has a density of 1.83 g/cm^3 and contains 94.0% of sulphuric acid by mass

(a) What is the mass of sulphuric acid in 1dm^3?
(b) What is the concentration of the sulphuric acid solution in mol/dm^3?

Answer 1

1.83 g/cm^3 = 1830 g/L. If 94% of the mass is sulfuric acid, then there are 1720 g of H2SO4 per liter of solution.

1720 g / 98 g/mole = 17.55 moles, so the concentration is 17.55 M.