Always calculate the required precipitant concentration . For (Ag_2S) (very small (K_sp)) vs. (CuS), the sulfide ion needed might be different due to stoichiometry.
[I−]remaining=8.5×10-171.8×10-9=4.72×10-8 Mopen bracket cap I raised to the negative power close bracket sub r e m a i n i n g end-sub equals the fraction with numerator 8.5 cross 10 to the negative 17 power and denominator 1.8 cross 10 to the negative 9 power end-fraction equals 4.72 cross 10 to the negative 8 power M Now, calculate the percentage of remaining I−cap I raised to the negative power ions relative to the initial
Write out the balanced dissolution equations and their corresponding equilibrium expressions for both potential precipitates. fractional precipitation pogil answer key
POGIL activities usually start with "Model 1," showing a visual diagram of beakers or a data table of Kspcap K sub s p end-sub
Step 2: Determine the Required Cation Concentration for Each Cation Always calculate the required precipitant concentration
A typical problem involves a solution containing two anions, such as Chloride ( Cl−Cl raised to the negative power ) and Chromate ( CrO42−CrO sub 4 raised to the 2 minus power ), to which a cation like Silver ( Ag+Ag raised to the positive power ) is slowly added.
The key to understanding fractional precipitation is , a measure of how much of a compound can dissolve in water. A smaller Ksp value means the compound is less soluble and will precipitate first when its ions are present. In the example above, AgI's much smaller Ksp explains why it precipitates before AgCl. [I−]remaining=8
(AgCl) (Silver chloride) precipitates first.
While POGIL (Process Oriented Guided Inquiry Learning) activities are designed for collaborative classroom discovery rather than direct answer retrieval, this guide breaks down the core concepts often found in the to help you master the material. 1. The Core Principle: Selective Solubility
To find how much of the first ion remains when the second begins to precipitate: cap K sub s p end-sub