Textbook Question
Use the appropriate values of Ksp and Kf to find the equilibrium constant for the reaction. FeS(s) + 6 CN-(aq) ⇌ Fe(CN)64-(aq) + S2-(aq)
Ch.18 - Aqueous Ionic Equilibrium
Tro6th EditionChemistry: A Molecular ApproachISBN: 9780137832217
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Table of contents
- Ch.1 - Matter, Measurement & Problem Solving118
- Ch.2 - Atoms & Elements106
- Ch.3 - Molecules and Compounds131
- Ch.4 - Chemical Reactions and Chemical Quantities56
- Ch.5 - Introduction to Solutions and Aqueous Solutions82
- Ch.6 - Gases114
- Ch.7 - Thermochemistry96
- Ch.8 - The Quantum-Mechanical Model of the Atom60
- Ch.9 - Periodic Properties of the Elements90
- Ch.10 - Chemical Bonding I: The Lewis Model89
- Ch.11 - Chemical Bonding II: Molecular Shapes, VSEPR & MO Theory85
- Ch.12 - Liquids, Solids & Intermolecular Forces51
- Ch.13 - Solids & Modern Materials47
- Ch.14 - Solutions90
- Ch.15 - Chemical Kinetics115
- Ch.16 - Chemical Equilibrium68
- Ch.17 - Acids and Bases136
- Ch.18 - Aqueous Ionic Equilibrium153
- Ch.19 - Free Energy & Thermodynamics93
- Ch.20 - Electrochemistry106
- Ch.21 - Radioactivity & Nuclear Chemistry74
- Ch.22 - Organic Chemistry140
Chapter 18, Problem 115
A solution is made 1.1⨉10-3 M in Zn(NO3)2 and 0.150 M in NH3. After the solution reaches equilibrium, what concentration of Zn2+(aq) remains?
Verified step by step guidance1
Identify the relevant chemical equilibrium: The complexation reaction between Zn(NO_3)_2 and NH_3 forms a complex ion, typically Zn(NH_3)_4^{2+}. The equilibrium can be represented as: Zn^{2+} + 4NH_3 \(\rightleftharpoons\) Zn(NH_3)_4^{2+}.
Write the expression for the equilibrium constant (K_f) for the formation of the complex ion: K_f = \(\frac{[Zn(NH_3)_4^{2+}\)]}{[Zn^{2+}][NH_3]^4}.
Determine the initial concentrations: Initially, [Zn^{2+}] = 1.1 \(\times\) 10^{-3} M and [NH_3] = 0.150 M. Assume [Zn(NH_3)_4^{2+}] = 0 M initially.
Set up an ICE (Initial, Change, Equilibrium) table to track the changes in concentrations as the system reaches equilibrium. Define the change in concentration of Zn^{2+} as -x, NH_3 as -4x, and Zn(NH_3)_4^{2+} as +x.
Substitute the equilibrium concentrations into the K_f expression and solve for x, which represents the change in concentration of Zn^{2+}. The equilibrium concentration of Zn^{2+} will be the initial concentration minus x.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Equilibrium in Chemical Reactions
Equilibrium in chemical reactions refers to the state where the rates of the forward and reverse reactions are equal, resulting in constant concentrations of reactants and products. In this context, understanding how the concentrations of Zn2+ and NH3 interact at equilibrium is crucial for determining the final concentration of Zn2+ in the solution.
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Chemical Equilibrium Concepts
Complex Ion Formation
Complex ion formation occurs when metal ions, such as Zn2+, interact with ligands like NH3 to form a complex. This process can significantly affect the concentration of free metal ions in solution, as the formation of complexes reduces the amount of free Zn2+ available, which is essential for calculating the equilibrium concentration.
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Le Chatelier's Principle
Le Chatelier's Principle states that if a system at equilibrium is disturbed, the system will adjust to counteract the disturbance and restore a new equilibrium. In this scenario, changes in concentration of NH3 or Zn(NO3)2 will shift the equilibrium position, impacting the concentration of Zn2+ ions in the solution.
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Related Practice
Textbook Question
A solution is 0.010 M in Ba2+ and 0.020 M in Ca2+. b. What is the remaining concentration of the cation that precipitates first, when the other cation begins to precipitate?
Textbook Question
A solution is 0.010 M in Ba2+ and 0.020 M in Ca2+. a. If sodium sulfate is used to selectively precipitate one of the cations while leaving the other cation in solution, which cation will precipitate first? What minimum concentration of Na2SO4 will trigger the precipitation of the cation that precipitates first?