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MERLOT II


    

Peer Review


Qualitative Analysis of Cations Applet

 

Ratings

Overall Rating:

4 stars
Content Quality: 4 stars
Effectiveness: 4 stars
Ease of Use: 4.25 starsstar
Reviewed: Apr 26, 2007 by Chemistry Editorial Board
Overview: This Java applet is a simulation that allows students to investigate various standard qualitative analysis methods, including cations, anions, iodine redox. The applet features five pages: 1) the lab manual, which sets up the experiment; 2) the lab bench, where the experiments are performed, 3) the notebook, which keeps a running record of the experiments performed and the results of the experiment; 4)a reactions page, which shows balanced equations and conditions for each of the possible reactions that can be performed to identify the presence of a particular species; and 5)a help page, which provides help not only in using the applet but also in conducting the qualitative analysis.
Learning Goals: Ultimately help students understand the methods of qualitative analysis. This is done with the simulation by letting the students perform reactions of selected cations and anions with specific reagents, make observations and identify unknowns.
Target Student Population: General chemistry students (typically second semester) or inorganic students.
Prerequisite Knowledge or Skills: Familiarity with a variety of chemical reactions, in particular solubilities of various ionic compounds, would be helpful but not necessary as all reactions are provided within the applet.
Type of Material: Simulation
Recommended Uses: This applet would be ideal as a prelaboratory assignment. The students would be able to see what various reactions occur as part of an analytical scheme. Known cations, for example, could be tested for reactions following an analytical flowchart. Unknown reactants or mixtures can also be investigated. This will hopefully improve the students ability to apply the flowchart quickly and effectively in the laboratory.
Technical Requirements: Standard computer platform with Java enabled browser.

Evaluation and Observation

Content Quality

Rating: 4 stars
Strengths: 1. Good selection of cations, reagents, anions.

2. Good set of chemical equations in the online lab book.

3. The material is thoroughly covered in the applet. The student would have little need for outside material if they were willing to study the resources thoroughly.
Concerns: 1. Qualitative analysis is typically done using a reaction flowchart. It would be useful if the applet provided students the ability to make one.

2. While the program identifies the unknowns when asked, the student is never asked to make an identification within the program.

3. It should inlcude an introduction to qualitative analysis with a flow chart showing selective precipitation and separation.

Potential Effectiveness as a Teaching Tool

Rating: 4 stars
Strengths: The strength is the extent of the material. All identification reactions are explicitly provided to the student. The reactions are also visually observable on the lab bench. The site offers an alternative or enhancement to qualitative analysis in the laboratory. It can appeal to multiple learning styles and multiple senses.
Concerns: 1. While solution colors are utilized in the program, for example, blue for the copper (II) ion, these colors are not extremely obvious in the visual presentation on the lab bench.

Ease of Use for Both Students and Faculty

Rating: 4.25 stars
Strengths: 1. Easy to navigate, does not trap the user.

2. For students, moving back and forth between the various pages will provide them with a wealth of information about the qualitative analysis process. They will be able to investigate systems before actually entering the lab.

3. For the instructor, the ability to assign one or more unknowns for the students to work through prior to lab is useful.
Concerns: 1. There is no record of the students success or failure to correctly identify the unknowns.

2. The simulation can be used but the instructions seem ambiguous and not easy or intuitive.

Other Issues and Comments: A good simulation of qualitative analysis that would be enhanced by including an introduction to the techniques and skills.