Quantitative Chemical Analysis
6 weeks · 0 milestones
Perform a quantitative chemical analysis using a standard analytical technique: titration (acid-base, redox, complexometric, or precipitation), gravimetric analysis, or spectrophotometric quantification. The proof is the raw data (all trial results, not just concordant ones), calculations with error propagation, comparison to a reference or literature value with calculated percentage error, and a written discussion of systematic and random error sources. For students without lab access, the accessible alternative is a rigorous error propagation analysis using published reference analytical data from NIST Standard Reference Data or IUPAC certified reference values for a named compound — the mathematical analysis of precision, accuracy, and error sources demonstrates the same analytical reasoning as laboratory work. Reviewed by a chemist who examines the raw data for internal consistency and the error analysis for correct error propagation methodology.
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3 milestones
Select a specific analyte, an appropriate quantitative analytical technique, and design the complete analysis protocol before any measurements are taken. Accessible alternative: if physical laboratory access is unavailable, select a published spectrophotometric, titrimetric, or chromatographic dataset from the NIST Chemistry WebBook or the analytical chemistry literature and conduct the quantitative calculation, calibration, and uncertainty analysis on published data — the statistical and analytical reasoning is identical.
Proof required
Submit your analyte specification (the chemical species being quantified and the sample matrix it is in), your chosen technique (titration, gravimetric, spectrophotometric, colorimetric, or equivalent) with a justification for why that technique is appropriate, your protocol for calibration (standards preparation, calibration range, number of calibration points), and your uncertainty budget identifying the main sources of measurement error.
What gets checked
- Technique justification is specific to the analyte and matrix — not 'spectrophotometry can measure concentrations' but 'UV-Vis spectrophotometry at 540nm is appropriate because the iron(II)–phenanthroline complex has a molar absorptivity of >11000 L/mol/cm in this wavelength region'
- Calibration protocol specifies at minimum 5 calibration standards spanning the expected analyte concentration range — not a single standard
- Uncertainty budget identifies instrument, calibration, sampling, and method contributions separately — at minimum three distinct sources