Mineral Solubility Calculations
Summary
Explores the pH dependence of the solubility of quartz, kaolinite, and rare earth phosphate, and familiarizes students with the use of the Geochemists Workbench programs "React" for creating reaction path models (sliding pH) and "Act2" for creating activity-activity diagrams.
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Context
Audience
Upper level undergraduate or graduate course in Geochemistry or Geochemical Modeling
Skills and concepts that students must have mastered
Basic thermodynamics. Background reading for use of the programs React and Act2 are part of the assignment.
How the activity is situated in the course
Homework assignment #2. The preceding homework assignment is also available as an activity sheet.
Goals
Content/concepts goals for this activity
To show students the strong pH dependence of mineral solubilities, which goes a long way towards explaining the compositions of natural waters.
Higher order thinking skills goals for this activity
Graph interpretation, synthesis of ideas, critical evaluation of competing models
Other skills goals for this activity
Use of the Geochemist Workbench programs React and Act2.
Description of the activity/assignment
Students use the Geochemist Workbench programs React and Act2 to explore the pH dependence of mineral solubility.
Determining whether students have met the goals
Students turn in GWB scripts and a Word file containing their answers to the questions, which I grade for accuracy.
More information about assessment tools and techniques.Teaching materials and tips
- Activity Description/Assignment (Microsoft Word 26kB Jun28 10)
- Solution Set (Microsoft Word 2007 (.docx) 77kB Jun28 10)
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Other Materials
- Background info and examples of reaction path models (PowerPoint 539kB Jun28 10)