At 20°C, an aqueous solution that is 18.0% by mass in ammonium chloride has a density of 1.0512 g/mL What is the molarity of ammonium chloride in the solution?

Answer 1

18% w/w means 18g NH4Cl/100 g solution.
mols NH4Cl = grams/molar mass = ?
Convert 100 g solution to L using density; then M = mols/L.