Status Key:
1. Activity ready for classroom use and testing
2. Activity in revision stage, may be available for use
3. Activity in Draft Stage
4.Activity Topic Identified
The Buffer Zone
Status: 1
Version: 3 (see version 1 here)
Authors:
Mary Walczak
Caryl Fish
General Topic: Buffers
Specific Topic:
| Effective range of a buffer |
Content Learning Objectives:
- Explain how the concentration of buffer components determines the pH of the solution
- Explain the effects of additions of strong acids/bases to buffered and non-buffered solutions
- Determine the relationship between the pKa of an acid and the optimal pH range of a buffer in order to select an appropriate buffer for a particular pH range
Process Learning Objectives:
- Interpret tabulated information (Information Processing)
- Recognize and predict trends in data (Critical Thinking)
- Generalize problem solutions (Problem Solving and Critical Thinking)
- Include all group members (Teamwork)
Prerequisites:
weak acid/base equilibrium calculations
Equilibrium – common ion effect
Conjugate acid/base pairs identity
Time Required: 55 minutes
Date Submitted: Feb. 21, 2009
The Importance of Ionic Strength
Status: 2
Version: 2 (see version 1 here)
Authors:
Juliette Lantz
Dave Langhus
Shirley G Fischer-Drowos
General Topic: Chemical Equilibrium - Solubility Activity
Specific Topic: electrolytes and ionic strength
Content Learning Objectives:
- Be able to describe the role of electrolytes in determining the ionic strength of solutions
- Be able to describe the effect of ionic strength on equilibrium concentrations
- Be able to calculate the ionic strength of a solution and predict its effect on equilibrium concentrations
Process Learning Objectives:
- Identifying key properties of electrolyte solutions (problem solving)
- Forming a shared understanding of microscopic solution interactions (teamwork)
- Challenging assumptions (critical thinking)
Prerequisites:
Calculate equilibrium concentrations using equilibrium constants
Familiarity with precipitation reactions and the solubility of sparingly-soluble compounds
Familiarity with the basic properties of an electroylte
Time Required: 50 minutes
Date Submitted: Feb. 8, 2009
Activity and Activity Coefficients
Status: 3
Content Learning Objectives:
- Be able to describe the effect of ionic strength on equilibrium concentrations
- Be able to differentiate the need to use activities vs. concentrations in equilibrium calculations
- Generate strategies for calculating activity coefficients and activities
- Be able to write equilibrium expressions using activities and to solve for equilibrium concentrations using activities
Process Learning Objectives:
- Predict trends in data (Information processing)
- Identifying similarities and differences (Critical thinking)
Multiple Equilibria - When Reactions Compete
Status: 3
Peer Reviewed: Yes
Version: 1
Authors:
Dave Langhus
Juliette Lantz
General Topics:
Chemical Equilibrium – Solubility
Chemical Equilibrium – Acids/Bases
Chemical Equilibrium – Complex Systems
Specific Topics:
pH dependence of sparingly soluble salts, examining multiple equilibria in aqueous soltuions
Content Learning Objectives:
- Explain how a competing equilibrium affects the solubility of a sparingly soluble compound in water.
- Predict the pH dependence of the solubility of a sparingly soluble salt.
Process Learning Objectives:
- Identifying key reactions (Problem solving)
- Challenging assumptions (Critical thinking)
- Predicting pH dependence (Information processing)
Prerequisites:
Be familiar with the weak acid-base properties of ions at the General Chemistry level.
Understand the principle of chemical equilibrium.
Be able to calculate the concentration of ions in a saturated solution of a sparingly soluble compound at the General Chemistry level.
Time Required: 60 minutes
Date Submitted: March 11, 2009
pH of Solutions of Strong Acids and Bases
Status: 2
Peer Reviewed: Yes
Version: 1
Authors:
Dave Langhus
Juliette Lantz
General Topics:
Chemical Equilibrium – Acids/Bases
Specific Topics:
Interaction of strong acids and bases with the autoionization of water.
Relative contribution of strong acid or base and water to pH
Making reasonable assumptions when calculating pH
Content Learning Objectives:
- Be able to calculate the pH of solutions containing any concentration of strong acid or base in water.
Process Learning Objectives:
- Be able to recognize when the result of a calculation makes sense (critical thinking)
- Identify assumptions (problem solving)
Prerequisites:
Familiarity with pH, the autoionization of water, and the dissociation of strong acids and bases at the General Chemistry level.
Be able to use activity coefficients to calculate the activity of an ion having known molar concentration.
Time Required: 100 minutes
Date Submitted: March 20, 2009