93 articles
Lab Techniques & Analysis
Titration, chromatography, spectroscopy, lab safety and how chemists identify substances.
How to Read a Safety Data Sheet (SDS)
A section-by-section guide to the 16-part Safety Data Sheet: hazard classification, H and P statements, first aid, firefighting, spill response, handling and storage, exposure limits and PPE, physical properties, stability, toxicology and disposal, with a worked example for a common lab chemical.
Spectroscopy: How Light Reveals Structure
An overview of spectroscopy for chemistry students: the electromagnetic spectrum, what each type of radiation does to atoms and molecules, and how UV–visible, infrared, NMR, mass spectrometry and atomic spectroscopy are used.
Thin-Layer Chromatography (TLC)
How thin-layer chromatography works and how to do it: preparing and spotting plates, choosing a solvent, visualising colourless spots with UV and stains, calculating Rf, and using TLC to check purity and follow reactions.
TLC vs Paper Chromatography
A side-by-side comparison of thin-layer and paper chromatography: stationary phases, how separation works, speed, resolution, sensitivity, visualising colourless spots, cost, typical uses in schools and research labs, and how to choose between them.
Measurement Uncertainty Practice Problems
Sixteen worked problems on measurement uncertainty: reading uncertainties of balances, burettes and pipettes, percentage uncertainty, combining uncertainties for sums, differences, products and quotients, titration and enthalpy examples, and comparing results with literature values.
UV–Visible Spectroscopy
How UV–visible spectroscopy works: electronic transitions, chromophores and conjugation, why things are coloured, reading an absorption spectrum and λmax, the spectrophotometer, and uses in analysis and biology.
Volumetric Analysis: Titrations of Every Kind
An overview of volumetric analysis: acid–base, redox, complexometric and precipitation titrations, direct and back titrations, primary standards and standardisation, with an example of each type and how to choose between them.
Disposing of Chemical Waste Responsibly
How school and university labs handle chemical waste: why most chemicals can't go down the sink, waste categories and separate containers, neutralising dilute acids and alkalis, heavy metals, halogenated solvents, sharps and broken glass, labelling, and reducing waste in the first place.
AAS vs ICP Techniques
Comparing atomic absorption spectroscopy with ICP-OES and ICP-MS for measuring metals: how each works, detection limits, one element at a time vs many at once, sample throughput, interferences, isotopes, running costs, and a guide to choosing the right technique for water, food, soil and clinical samples.
Atomic Absorption Spectroscopy
How atomic absorption spectroscopy (AAS) measures metal concentrations: atomising samples in a flame or furnace, hollow cathode lamps, why each element absorbs specific wavelengths, calibration, and uses from drinking water to blood lead.
Column Chromatography
How to purify compounds by column chromatography: choosing the stationary phase and eluent with TLC, packing the column, loading the sample, collecting and analysing fractions, flash chromatography and common problems.
EDTA Titrations and Water Hardness
How EDTA forms stable 1:1 complexes with metal ions, why pH 10 buffers and Eriochrome Black T are used, a full method for measuring water hardness, worked calculations in mg/dm³ as CaCO₃, and other uses of complexometric titration.
Conductometric Titrations
How following electrical conductivity during a titration reveals the end point without an indicator: why H⁺ and OH⁻ conduct so well, the V-shaped graphs for strong and weak acids, precipitation titrations, and practical tips.
Elemental (CHN) Analysis
How a CHN analyser burns a milligram sample to measure carbon, hydrogen, nitrogen and sulfur, how oxygen is found, the classic Pregl and Liebig methods, worked calculations to an empirical formula, the ±0.4% purity rule, and the limits of the technique.
Gas Chromatography: How It Works
How gas chromatography separates volatile compounds: the carrier gas, the column, the oven and detectors, retention times, reading a chromatogram, measuring amounts from peak areas, and GC–MS in forensics and testing.
Gas Chromatography vs HPLC
A detailed comparison of gas chromatography and high-performance liquid chromatography: mobile and stationary phases, which samples each can handle, temperature, detectors, speed, resolution, cost, coupling to mass spectrometry, and a decision guide with real examples.
Gravimetric Analysis Practice Problems
Twelve gravimetric analysis problems with full solutions: precipitating sulfate as BaSO₄ and chloride as AgCl, gravimetric factors, heating to constant mass, water of crystallisation, thermal decomposition, percentage purity, mixtures and evaluating sources of error.
HPLC Explained
How high-performance liquid chromatography works: pumps, columns, reversed-phase separation, detectors, retention time and peak area, and why HPLC is the workhorse of pharmaceutical, food and clinical analysis.
ICP-MS: Measuring Trace Metals
How inductively coupled plasma mass spectrometry measures dozens of elements at parts-per-trillion levels: the argon plasma, ion sampling, mass analysis, interferences, isotope ratios, and uses from water safety to geology.
IR vs NMR Spectroscopy
A clear comparison of infrared and NMR spectroscopy: what each measures, the physics behind them, what information each gives, sample requirements, cost and speed, strengths and blind spots, and how chemists combine them, with worked examples of isomers that one technique can tell apart and the other can't.
Measuring Iron in Supplement Tablets
An advanced practical to find the mass of iron in iron(II) sulfate supplement tablets by redox titration with potassium manganate(VII): the chemistry, method, full worked calculation from sample data, comparison with the label, errors, and an alternative colorimetric method.
Nuclear Magnetic Resonance: How MRI and NMR Work
The physics and chemistry of NMR: nuclear spin, magnetic fields and radio waves, chemical shift, shielding, TMS, how NMR reveals molecular structure, and how the same principle creates MRI scans in hospitals.
Potentiometric Titrations
How measuring electrode potential during a titration locates the equivalence point precisely: indicator and reference electrodes, pH titrations, redox titrations with platinum electrodes, derivative plots and automatic titrators.
Precipitation Titrations: Mohr's Method
How chloride and other halides are measured by titration with silver nitrate: Mohr's method with chromate indicator, Volhard's back titration with thiocyanate, Fajans' adsorption indicators, worked examples and sources of error.
Propagating Uncertainties Through Calculations
How uncertainties combine in sums, products, powers and logarithms, the simple and quadrature rules, uncertainty from repeated measurements (standard deviation and standard error), with chemistry examples from titrations to Ka.
Raman Spectroscopy
How Raman spectroscopy identifies molecules from the tiny fraction of laser light they scatter with changed energy: Rayleigh vs Raman scattering, Raman shift, how it complements infrared, and uses from drug checking to art and Mars.
Sampling: Why the First Step of Analysis Matters Most
Why a perfect measurement on a bad sample gives a wrong answer: representative samples, heterogeneity, random, systematic and composite sampling, how much sample to take, subsampling by coning and quartering, preservation, chain of custody, and worked examples from soil, water and food.
Spectroscopy Misconceptions
Eleven misconceptions students hold about spectroscopy and mass spectrometry, corrected with clear explanations: why coloured solutions absorb the opposite colour, what IR bands really measure, why the tallest mass spectrum peak isn't always the molecular ion, what NMR splitting counts, and more.
Spectroscopy Practice Questions
Advanced practice problems combining mass spectrometry, infrared, ¹³C NMR and ¹H NMR to deduce structures, from single-technique questions to full combined-data problems, each with a step-by-step worked answer and the reasoning behind every deduction.
Standard Deviation in Chemistry Data
Worked examples of standard deviation for chemistry: calculating sample standard deviation step by step, relative standard deviation, standard error of the mean, 95% confidence intervals with t-values, comparing two methods, and the Q-test and Grubbs' approach for outliers.