Resumen de Measuring Soil Phosphates Using Ion-Exchange Resins:: A Final Project for Freshman Chemistry

Arlyne M. Sarquis, Donald A. Storer

• The chemistry of soils and fertilizers provides an opportunity to teach a variety of fundamental concepts at the freshman level. A model final project for freshman chemistry that uses a discovery-based scenario is described. The effect of solubility of compounds in a practical application is illustrated by allowing the student to discover that limestone (calcium carbonate) will react with phosphates in soils to produce insoluble compounds. The phosphate in the soil is isolated by a mixed-bed, anion-cation exchange resin capsule and analyzed spectrophotometrically. A laboratory notebook is kept on the project and a final written report is submitted at the end.