Fractional Precipitation Pogil Answer Key

, you cannot compare them directly because they have different ion ratios (1:1 vs. 2:1). You must calculate the needed to start precipitation for both. For Ag2CrO4cap A g sub 2 cap C r cap O sub 4 :

AgCl(s) will begin to precipitate when [Ag⁺] ≈ 1.8 × 10⁻⁹ M.

) will as it forms a solid, while the other ion concentration remains steady until its own Kspcap K sub s p end-sub is reached. Typical Extension Problems & Calculations fractional precipitation pogil answer key

will rise. It will hit the lower threshold first, causing that specific solid to form while the other ion remains completely dissolved.

Fractional precipitation is a laboratory technique used to separate ions in a solution by adding a reagent that forms a precipitate with one or more of those ions. Because different salts have different solubilities (represented by the solubility product constant, ), they don't all precipitate at the same time. , you cannot compare them directly because they

Hg₂Cl₂ has the smallest Ksp (1.3 × 10⁻¹⁸), so it will precipitate first.

To help you work through your specific worksheet problems, tell me: What are you trying to separate? What are their given Kspcap K sub s p end-sub values or initial concentrations ? For Ag2CrO4cap A g sub 2 cap C

[Ag⁺] = Kₛₚ(AgI) / [I⁻] = (8.5 × 10⁻¹⁷) / (0.10) = 8.5 × 10⁻¹⁶ M