ABSE_Acid-Base and Solution Equilibrium Module Overview

Acid-Base and Solution Equilibrium Module Overview

Introduction

image of orange In this module you will learn that not all acid and base reactions go to completion. Instead, they establish equilibrium. This changes the way we do calculations involving these reactions. Acid-base equilibrium expressions have their own constants, k_a and k_b. You will perform numerous calculations involving these constants. In addition, you will learn about buffers, titrations involving weak acids and bases, solution equilibrium, k_sp, the common ion effects, and how to predict precipitates.

Module Lessons Preview

What is a Brønsted acid and base?
What are conjugate acids and bases?
What does the term pH represent?
What is the relationship between pH and pOH?
What is the mathematical relationship between pH, [H+], pOH, and [OH-]?
How do periodic trends contribute to acid and base strengths?
What is the difference between strong and weak acids or bases as percent ionization?
What is Ka and Kb?
What is the relationship between Ka and pKa (or Kb and pKb)?
How do you calculate Ka and Kb from equilibrium concentrations?
How do salts act as acids and bases?
How do you solve equilibrium calculations with the quadratic equation?
What is the definition of the term buffer?
What makes a buffer system different from a non-buffered one?
What is buffer capacity?
How can a titration endpoint be determined to be acidic, basic, or neutral based on the strengths of the acid and base in the system?
How do acid-base indicators work?
How is the pH determined for various salt solutions?
What is Ksp and how is it used in calculations?
What is the common ion effect?

Key Terms

Acid Ionization Constant, Ka - the equilibrium constant specific to the ionization equation for a weak acid $LaTeX: k_{a}=\frac{[H_3O^{+}][A-]}{[HA]}$ $k_{a}=\frac{[H_3O^{+}][A-]}{[HA]}$
Acidic Solution - an aqueous solution in which [H+]>[OH-]
Amphoteric Compound - a compound that can act either as an acid or a base
Analyte - the solution placed in the receiving flask in titration
Base Ionization Constant, Kb - the equilibrium constant specific to the ionization equation for a weak base $LaTeX: k_b=\frac{[BH^+][OH^{-}]}{[B]}$ $k_b=\frac{[BH^+][OH^{-}]}{[B]}$
Basic Solution - an aqueous solution in which [H+]<[OH-]
Brønsted-Lowry Acid - a proton (H+) donor
Brønsted-Lowry Base - a proton (H+) acceptor
Buffer - a pair of solutes that can keep the pH of a solution almost constant if either acid or base is added; a solution containing such a pair of solutes
Buret - long, thin graduated tube used in titration
Common Ion - the ion in a mixture of ionic substances that is common to the formulas of at least two
Common Ion Effect - the solubility of one salt is reduced by the presence of another having a common ion
Conjugate Acid - the species in a conjugate acid-base pair that donates a proton and has the greater number of H+ units
Conjugate Acid-Base Pair - two substances (ions or molecules) whose formulas differ by only one H+ unit
Conjugate Base - the species in a conjugate acid-base pair that accepts a proton and has the fewer number of H+ units
End Point - the moment in a titration when the indicator changes color and the titration is ended
Equivalence Point - the moment in a titration when the number of equivalents of a reactant added from a buret equals the number of equivalents of another reactant in the receiving flask
Indicator - usually a weak acid that is added to an analyte to provide a color change at a desired endpoint
Ion Product - the mass action expression for the solubility equilibrium involving the ions of a salt and equal to the product of the molar concentrations of the ions, each concentration raised to a power that equals the number of ions obtained from one formula unit of the salt
Ion Product Constant of Water, Kw- Kw=[H+][OH-]=1x10-14
Molar Solubility - the number of moles of solute required to give 1 L of a saturated solution of the solute
Neutral Solution - an aqueous solution in which [H+]=[OH-]
Percentage Ionization - amount of ion produced per amount of ion available time 100
pH - -log[H+]
pKa - -log Ka
pKb - -log Kb
Polyprotic Acid - an acid with more than one available H+
Solubility Product Constant - the equilibrium constant for the solubility of a salt and that, for a saturated solution, is equal to the product of the molar concentrations of the ions, each raised to a power equal to the number of its ions in one formula of the salt
Strong Acid - an acid that ionizes 100%
Strong Base - an base that ionizes 100%
Titrant - the solution placed in the buret
Titration - a common laboratory technique used to determine the unknown concentration of a solution
Titration Curve - the plot of the pH of a solution at different stages of a titration against the volume of titrant added
Weak Acid - an acid that does not ionize 100%
Weak Base - an base that does not ionize 100%

eTextbook Reminder

As you read these content pages, also read the corresponding content in your etextbook. Work the example problems in the text as you read to make sure that you understand. The etextbook sections will be listed with the corresponding content pages on your schedule.

Acid-Base and Solution Equilibrium Practice Problems

Before you begin, print the module practice problems found below. You should complete a section of problems after covering that particular portion of the content.

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