Mineral Solubility Calculations

John C. Ayers
,
Vanderbilt University
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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

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