Calculate the molar concentration of an aqueous solution of NH3 at 10.9%w (d = 950 g L-1).

Molar concentration has units of moles of solute per liter of solution. Given the percent by mass and the density of the solution, we ca easily convert the concentration into molarity as follows:

10.9 g NH3 / 100 g solution (950 g / L) (1 mol / 17.04 g) = 6.08 mol NH3 / L solution