Comparison of the Electromagnetic Spectra of Common Light Sources: A General Chemistry Laboratory Exercise

Maslowsky, Jr. Edward

doi:10.1021/ed200658y

Cited by 4 publications

(1 citation statement)

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“…Technological advances have made devices like emission and absorption spectrometers more portable and affordable, providing opportunities to incorporate these techniques into large classes which would not have been previously feasible. While portable and comparatively inexpensive absorption spectrometers have been broadly available for several years, atomic emission can now be studied using simple emission spectrometers, studying atomic line spectra and continuous spectra from several lamp sources − and from a series of flame tests. ,− Absorption studies can be carried out using simple spectrometers, allowing for the comparison between absorption and emission instrumental techniques.…”

Section: Introductionmentioning

confidence: 99%

Exploring Emission and Absorption Spectroscopy in the First-Year General Chemistry Laboratory

et al. 2020

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In the first-year general chemistry laboratory course, instrumental data collection involving sample quantification has often been limited to absorption spectroscopy due to the inaccessibility of emission techniques suitable for large enrollments and novice users. In this laboratory experiment, students explore the complementary techniques of emission and absorption spectroscopy, in which sample quantification respectively occurs via the measurement of light emitted or absorbed by the sample. Calibration curves are constructed for both techniques. Eschewing atomic absorption spectroscopy (AAS) and inductively coupled plasma atomic emission spectroscopy (ICP-AES), instrumentation not typically available for large general chemistry courses, quantitative data is instead collected using a series of carefully implemented flame tests. Students perform flame tests on alkali, alkaline earth, and transition metal compounds using the emitted light to gain a thorough understanding of emission spectroscopy. In Week 1, students are introduced to emission spectroscopy through the identification of unknown components in air, lamps, and contaminated soil samples. In Week 2, students carry out quantitative emission and absorption characterization of Na and Cu solutions, comparing the two techniques through experimental observations and analyzed results. Calibration curves with high linear regressions (r 2 > 0.992) are prepared and used to determine the concentrations of provided reference samples, with averaged student data resulting in reasonably low percent errors (<12% for Na emission, <11% for Cu emission, and <2% for Cu absorption) when compared to the known concentrations. Students then compare experimental flame emission results to provided ICP data to gain experience with a sensitive, quantitative emission technique.

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