The density of a solution that is 18.0% by mass lead nitrate [Pb(NO₃)₂] is 1.18 g/cm³. Calculate the molarity of the lead nitrate solution.

Question

Quizplus · Accepted Answer

To calculate the molarity of the lead nitrate solution, we first need to find the mass of lead nitrate in 1 liter (1000 mL) of solution. Given that the density is 1.18 g/cm³, 1 liter of solution has a mass of 1180 g. With an 18.0% by mass concentration, the mass of lead nitrate in this volume is 0.18 × 1180 g = 212.4 g. The molar mass of lead nitrate [Pb(NO3)2] is approximately 331 g/mol (207 for Pb, 14 for each N, and 16 for each O, with 6 O atoms total). Thus, the number of moles of lead nitrate in 1 liter of solution is 212.4 g / 331 g/mol ≈ 0.64 mol. Therefore, the molarity, which is moles of solute per liter of solution, is approximately 0.64 M.

The Density of a Solution That Is 18