A solution of H2SO4 (aq) with a molal concentration of 5.25 m has a density of 1.266 g/mL. What is the molar concentration of this solution?

There are a number of ways to express concentration of a solution. This includes molarity and molality. Molarity is expressed as the number of moles of solute per volume of the solution. MOlality is expressed as moles per kg solution.

5.25 mol H2SO4 / kg solution (1 kg / 1000 g) (1.266 g / mL) (1000 mL / 1L) = 6.6 M H2SO4