(Leave empty for random seed, 1–4096)
By carefully controlling the concentration of the precipitating agent, you can force the least soluble salt to drop out of the liquid while keeping the more soluble ions in the solution. Core Concepts You’ll Find in the POGIL 1. The Role of Kspcap K sub s p end-sub Kspcap K sub s p end-sub
to find the exact point where the solution becomes saturated. For Silver Iodide ( AgIcap A g cap I
Disclaimer: This guide is intended to aid in understanding the concepts of the POGIL activity and should be used as a study aid rather than a direct copy-paste answer key.
The compound that requires the lowest concentration of the added reagent ( Ag+cap A g raised to the positive power ) to precipitate first. Q3: Calculating Concentration at Separation fractional precipitation pogil answer key
of its original concentration, the separation is considered effective. 3. Step-by-Step Problem Solving Strategy To excel at the POGIL activity, follow these steps: Look up the Kspcap K sub s p end-sub values for all potential precipitates. Determine the required concentration: Calculate the needed for each ion to start precipitating ( Order the ions: The ion requiring the lowest precipitates first. Calculate remaining concentration: Use the
8.5×10-17=[Ag+](0.10)8.5 cross 10 to the negative 17 power equals open bracket cap A g raised to the positive power close bracket open paren 0.10 close paren
values of the two possible products. Because both salts produce a 1:1 ratio of ions ( For Silver Iodide ( AgIcap A g cap
Step 2: Find the Concentration of the First Ion Remaining when the Second Begins to Precipitate The second precipitate ( AgClcap A g cap C l ) will begin to form as soon as the Ag+cap A g raised to the positive power concentration hits . At this exact moment, you can calculate how much Br−cap B r raised to the negative power is left dissolved in the solution by plugging this Ag+cap A g raised to the positive power value back into the AgBrcap A g cap B r Kspcap K sub s p end-sub expression.
The fractional precipitation POGIL illustrates that the ion forming the salt with the cap K sub s p end-sub
When a reagent is added to a solution containing multiple ions, it will react with all of them to form potential precipitates. However, the precipitates do not form simultaneously. The compound with the lower solubility will reach its saturation point first and begin to precipitate out of the solution, while the more soluble compound remains dissolved until a higher concentration of the precipitating ion is added. Key Factors Determining Order of Precipitation Kspcap K sub s p end-sub the separation is considered effective.
Graphical Analysis: Some POGILs include plots showing the decrease in ion concentration as the reagent is added, providing a visual representation of the equilibrium shifts. Why Seek an Answer Key?
To find out how much of the first ion remains in solution when the second compound just begins to precipitate, substitute the higher required for the second precipitation back into the Kspcap K sub s p end-sub expression of the first compound.