Dry Qualitative Unknowns

INSTRUCTOR TIME SAVER

Prepared individual samples eliminate the need to label and fill racks of test tubes for each analysis group. The removable adhesive code number may be placed in the grade book indicating the unknown assignment. By referring to the key, you may be confident of the ion each student should report.

EDUCATIONAL AND EASY TO USE

Students have the opportunity to dissolve a solid and consider the fact that both cations and anions are present. The unknown solid needs just a few seconds to dissolve and the sample is ready for analysis.

RELIABLE

The raw materials are reagent grade. No inert fillers are added and no trace elements are present except those listed by the manufacturer. The sample size is between 0.37 & 0.40 g with approximate equal amounts by weight of each raw material. The exception is Ag + which is high purity and 0.25 & 0.30 g. The unknowns have a stable shelf life.

REDUCE STORAGE SPACE

Storage space needed for raw material bottles and the various known and unknown solutions may easily use several shelves in the storeroom. The ziplock packets require little storage space.

MANY COMBINATIONS

For each analysis group, there are several possible ion combinations. The packet is colored blue to provide an uniform appearance and to disguise the various metal ion colors.

CONTROL COSTS

A fixed amount of material is provided to each student at a known cost. Students may be charged if an extra packet is required. Purchase only the number of unknowns needed.

OTHER USES

Anions and cations may be studied by infrared spectroscopy, paper chromatography, ion exchange chromatography, and emission spectroscopy.