Use of a computer controlled spectrophotometer in home chemistry

experiments

Lawton Shaw and Robert Carmichael

Centre for Science, Athabasca University

Athabasca University

• 38,000 students (7,900 FLE)

• Open registration• Average age: 29• 83% work while

they study• Students from

across Canada and abroad

Home Labs at AU

• General Chemistry I (>500 students per year)• Home lab kit ships anywhere within Canada

Criteria for Home Lab Experiments

Practical:• Need durable equipment• Low cost• Small size/weight• Reliable experiments• Safety & low chemical

toxicity• “Green”

Lab Curriculum:• Meaningful experiments• Quantitative

measurements where possible (e.g. mass, volume, etc…)

• Introduction to instrumentation?

Home Experiments

1. Candle (observational)

2. Mass, volume

3. Spectrophotometry

4. Acid/base titrations

5. Gas constant

6. Colligative properties

7. Reaction Enthalpy

8. Qualitative cation determination

9. Quantitative analysis of P

10. Reaction stoichiometry (iodate, iodide)

Home-made colorimeter

D. Kennepohl and M. Connors ‘An Inexpensive Mini-colorimeter for Undergraduate Science Laboratories, Australian Journal of Education in Chemistry, 2010, 70, 38-41

Vernier SpectroVis Plus

• CCD array• 380-950 nm, 2.5 nm

resolution• 1 s spectral acquisition• Powered with USB

connection• PC controlled• Downloadable software

(free)• < $500

Experiment: Determining %ASA in an aspirin tablet

Student Data – Spectrum of Fe(III) salicylate complex

Student Calibration Data

SpectroVis Plus

• Approx. 250 shipped to date• No damage to instruments

(so far!)• Much positive feedback from

students and tutors• Students satisfied with good

data quality

Problems/Criticisms

• Students may have difficulty installing software (infrequent and always resolved)

• Software does too much of the work for students (i.e. black box type calculations)

New learning experiences for students

• Computer control of an instrument (e.g. setting parameters)

• Instrument calibration• Electronic capture of data• Electronic data processing

What we’re working on…

• Preparing to survey students on their previous experience with instrumentation, and how they rate their learning experience

• New home lab experiments with the SpectroVis

Acknowledgments

• Chemistry 217 tutors (Jim Robinson, Nyron Jaleel, Klaus Thomson, Kate Stuttaford)

• Lab Kit Manager, Neil Sexton• Knowledge Infrastructure Program• Athabasca University