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Ch.17 - Aqueous Ionic Equilibrium
Chapter 17, Problem 104

Predict whether a precipitate will form if you mix 175.0 mL of a 0.0055 M KCl solution with 145.0 mL of a 0.0015 M AgNO3 solution, and identify the precipitate, if any.

Verified step by step guidance
1
Calculate the moles of KCl in the solution using the formula: moles = concentration (M) \times volume (L).
Calculate the moles of AgNO3 in the solution using the formula: moles = concentration (M) \times volume (L).
Determine the total volume of the mixed solution by adding the volumes of the KCl and AgNO3 solutions.
Calculate the concentrations of K^+ and Cl^- ions from KCl, and Ag^+ and NO3^- ions from AgNO3 in the mixed solution using the formula: concentration = moles / total volume (L).
Use the solubility product constant (K_sp) for AgCl to determine if the product of the concentrations of Ag^+ and Cl^- ions exceeds K_sp, indicating the formation of a precipitate.

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Solubility Product Constant (Ksp)

The solubility product constant (Ksp) is a numerical value that represents the equilibrium between a solid and its ions in a saturated solution. It is specific to a particular ionic compound and helps predict whether a precipitate will form when two solutions are mixed. If the product of the concentrations of the ions in solution exceeds the Ksp, a precipitate will form.
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Precipitation Reactions

Precipitation reactions occur when two soluble salts react in solution to form an insoluble salt, known as a precipitate. This process is driven by the formation of a compound that has low solubility in water. In this case, mixing KCl and AgNO3 can lead to the formation of AgCl, which is a common precipitate in such reactions.
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Molarity and Dilution

Molarity is a measure of concentration defined as the number of moles of solute per liter of solution. When mixing solutions, the total volume changes, and the concentrations of the ions must be recalculated to determine if a precipitate will form. The dilution of the original solutions affects the final concentrations of K+ and Ag+ ions, which are crucial for assessing the potential for precipitation.
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