Posted Guided Inquiry Activities Available
The activities listed below have been posted for immediate use without undergoing a peer review process.
They are posted here for use by all. Feel free to download them, read them, use them or be inspired by them. Please acknowledge the authors and the ANA-POGIL website if you use these materials in your classroom.
Topics:
Introduction to Laboratory Statistics
Using Concentration and % weight
The Precipitation Titration Curve
Specifying and Preparing pH buffers
Using Concentration and % weight
Peer Reviewed: No
Version: 1
Authors:
Larry Margerum
General Topics:
Concentration
Specific Topics:
Reveiw of concentration units and % by weight
Objectives:
Recognize the meaning of ppm and use it correctly with dilute aqueous solutions
•Recognize that % weight is related to ppm; be able to interconvert
•Be able to follow and write directions on preparing solutions using %wt or ppm
Prerequisites:
General Chemistry
Time Required: 45 minutes
Date Submitted: September 5, 2006
Other Notes:
Usually given on the first day of sophomore analytical chemistry
Single Beam Spectrometer
Peer Reviewed: No
Version: 1
Authors:
Caryl Fish
Phil Palko
General Topics:
Spectrophotometry
Spectrophotometers
Specific Topics:
Spectronic 20 components and function
Objectives:
Students will be able to identify the components of a single beam instrument and describe the function of each component
Prerequisites:
Beer's Law
Time Required: 30 minutes
Date Submitted: September 18, 2006
Other Notes:
Best if students have access to actual spectrophotometer.
The Precipitation Titration Curve
Peer Reviewed: No
Version: 1
Authors:
Dave Langhus
General Topics:
Chemical Equilibrium – Solubility
Titrations
Specific Topics:
The shape of the titration curve
Calculating analyte and titrant concentrations at any point during the Mohr titration
Some factors affecting the success of the Mohr titration
Objectives:
Become familiar with the shape of the Mohr titration curve
Be able to calculate analyte and titrant concentrations at any point during the Mohr titration
Understand the role of Ksp in the feasibility of the Mohr titration
Prerequisites:
An understanding of basic solubility equilibria and ability to formulate and apply the Ksp expression
An understanding of the concept of formal concentration is central to the treatment.
Time Required: 90 minutes
Date Submitted: October 10, 2006
Other Notes:
I’ve used this once with five students
There were some serious issues with 15 – 18. There isn’t as much data as they’d like to establish trends
Specifying and Preparing pH Buffers
Peer Reviewed: No
Version: 1
Authors:
Dave Langhus
General Topics:
Chemical Equilibrium – Acids/Bases
Buffers
Specific Topics:
Using the Henderson-Hasselbach approximation to make a recipe for preparing a buffer.
Affect of adding acid or base to a buffered solution
Buffer Capacity
Why the pH of a carefully prepared buffer is wrong
Objectives:
Be able to design and describe the preparation of a pH buffer
Understand the notion of buffer capacity and some factors that impact it
Understand the limitations of this approach in achieving the desired pH
Prerequisites:
A General Chemistry level understanding of weak acid-base chemistry
Formal concentrations are used liberally.
Time Required: 0 minutes
Date Submitted: October 10, 2006
Other Notes:
I’ve used this once with five students
There were no serious sticking points.
Acid-Base Ionic Distribution
Peer Reviewed: No
Version: 1
Authors:
Dave Langhus
General Topics:
Chemical Equilibrium – Acids/Bases
Polyprotic Acid-Base
Specific Topics:
The dissociation of one-, two- and three-protic acids, including alpha-amino acids, and polyacidic bases
Building an ability to visualize the way these species vary in concentration with pH using graphs
Objectives:
Get a feel for the concentration distribution of acids and their conjugate bases as a function of pH
Be able to identify the prinicipal species present in solutions of acids and bases at a given pH
Prerequisites:
A General Chemistry level understanding of weak acid-base equilibria
Some formal concentrations are specified.
Time Required: 80 minutes
Date Submitted: October 10, 2006
Other Notes:
I’ve used this once with five students
There were no serious sticking points.
The Acid-base Distribution Functions
Peer Reviewed: No
Version: 1
Authors:
Dave Langhus
General Topics:
Chemical Equilibrium – Acids/Bases
Polyprotic Acid-Base
Specific Topics:
Definition of alpha and derivation of the functions for a monoprotic acid
Using the distribution functions
Formulating distribution functions for polyfunctional acids by analogy
Objectives:
Understand the origin and nature of the acid-base fractional distribution functions
Be able to use the acid-base fractional distribution functions to calculate ionic concentrations at a given pH
Prerequisites:
Familiarity with the dissociation of polyfunctional acids and bases
The concept of formal concentration is central to this treatment.
Time Required: 60 minutes
Date Submitted: October 10, 2006
Other Notes:
I’ve used this once with five students
There were no serious sticking points.
Analytical Complexation
Peer Reviewed: No
Version: 1
Authors:
Dave Langhus
General Topics:
Chemical Equilibrium – Complex Systems
Specific Topics:
The affect of the presence of a ligand on metal ion concentration as a function of pH
Looking up Kf values, the conditional formation constant, the concept of CT
Calculating analyte and titrant concentrations during the course of the complexometric titration
Objectives:
Be able to set up complexation equilibrium problems and solve those that are reasonable.
Become aware of some pitfalls in conventional approaches to complexation equilibrium
Be able to calculate the analyte and titrant concentration at any point during the complexometric titration.
Prerequisites:
Familiarity with weak acid-base equilibria and the fractional distribution functions
A General Chemistry level awareness of complexation
The concept of formal concentration is central to this treatment.
Time Required: 130 minutes
Date Submitted: October 10, 2006
Other Notes:
I’ve used this once with five students.
There were serious issues with item 23. Coming up with these concentrations might require a level of ingenuity that benefits from experience. At least more breakdown is probably in order