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Chemistry 17: 1-3

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The Common Ion Effect

Chapter 17: 1-3 Homework

Reading Preparation

Textbook assignment: Read Kotz and Triechel, Chemistry and Chemical Reactivity Chapter 17: Sections 1 to 3.

Study Notes

Our main goal in this chapter is to understand and apply the principles of the common ion effect. This concept grows out of conservation of energy, and Le Chatelier's principal that when a system is in equilibrium, it will respond to a disturbance by attempting to return to equilibrium or establishing new equilibrium.

Key Formula

Buffer SolutionFormulaNotes
Hydronium concentration [ H 3 O + ] = [ acid ] [ conjugate base ] K a [] indicate concentrations
Buffer solution pH pH = p K a + log [ conjugate base ] [ acid ]
Equivalence PointpH = 7.00 at 25°CSolution contains neutral salt
Titration: weak acid, strong base [ H 3 O + ] = [ weak acid remaining ] [ conjugate base produced ] K a

OR pH = p K a + log [ conjugate base produced ] [ weak acid remaining ]

When [conjugate base] = [acid remaining], log [1] = 0 and

pH = pKa

Web Lecture

Read the following weblecture before chat: Common Ions

Study Activity

Videos for Chapter 17: Principles of Chemical Reactivity: Other Aspects of Aqueous Equilibria

Review the Videos at Thinkwell Video Lessons.

    • Reactions of Acids and Bases
      • The Common Ion Effect
    • Buffers
      • An Introduction to Buffers
      • Acidic Buffers
      • Basic Buffers
      • The Henderson-Hasselbalch Equation
    • Acid-Base Titration
      • Strong Acid-Strong Base Titration
      • Weak Acide-Strong Base Titration
      • Polyprotic Acid-Strong Base Titration
      • Weak Base-Strong Acid Titration
      • Acid-Base Indicators

Follow the instructions at the Chem Collective to perform the Virtual Lab: Creating a Buffer Solution. If you have not used the Chem Collective before, watch the introductory video and support information.

  • Read the "Buffer Creation" problem statements.
  • Determine How much HAc, HCl, and NaAc you will need to create the buffer solution.
  • Carry out your experiment and create your solution.
  • What happens when you add more HCl?
  • What happens when you add more NaAc?

Chat Preparation Activities

Chapter Quiz

(Aligns to) AP #14 GUIDED INQUIRY — Creating an effective buffer solution — Phase I

Building on what you learned with Experiment #13, design a buffer solution with a target pH and buffer capacity by selecting appropriate conjugate-acid base pairs.