Question

Calculate the number of milligrams of Ag2CrO4 that would dissolve in 400.0mL of distilled water. Use your average Ksp from the experiment. (Average Ksp is 1.58x10^-11)

Answer 1

Ag_2 Cr O_4 (s) rightharpoonoverleftharpoon 2 Ag^+ () + Cr O^-_4 () K_sp = [Ag^+]^2 [Cr O^-_4]/1 for solid [] = 1 initially Ag_2 Cr O_4 Ag^+ Cr O^-_4 A 0 0 change -x 2x x equilibrium A - x 2x x K_sp = [x]^2 [x]/1 = 1.58 times 10^-11, x = 2.53 times 10^-4 M \r\n Moles dissolved = x = 2.53 times 10^-4 M molarity = moles/volume (in litres) volume (v) = 400 ml = 0.4 L moles = 2.53 times 10^-4 M times 0.4 L = 0.000101207 moles Mass of 1 mole Ag_2 Cr O_4 = 331.73 g/mol = 0.000101207 mol times 331.73 g/mol = 0.03357 g = 33.573 mg