93 articles
Lab Techniques & Analysis
Titration, chromatography, spectroscopy, lab safety and how chemists identify substances.
Running Safe, Successful Chemistry Practicals
A practical guide for chemistry teachers on planning and running lab lessons: trialling experiments, technician communication, risk assessment, clear routines, pre-lab questions, managing the room, keeping students thinking rather than just following steps, and effective follow-up.
Weighing Accurately with an Electronic Balance
How to weigh solids and liquids accurately on top-pan and analytical balances: taring, weighing by difference, avoiding draughts and static, hygroscopic substances, weighing to constant mass and calculating uncertainty.
How Drinking Water Is Tested
What water labs measure and how: microbes, chlorine, pH, hardness, nitrate, lead and other metals, fluoride and emerging contaminants, the instruments behind each test, what home test kits can and can't tell you, and how to read a water quality report.
Flame Test Colours: Identifying Metals by the Light They Give Off
The flame test colours of lithium, sodium, potassium, calcium, strontium, barium and copper, why each metal gives a characteristic colour, how to do the test, its limitations, and the chemistry of fireworks.
Analytical Chemistry Study Guide
A structured revision guide to analytical chemistry: key vocabulary, titrations, gravimetric analysis, chromatography, spectroscopy and mass spectrometry, data and uncertainty, a technique-selection table, exam-style checkpoints and a two-week revision plan with links to every topic.
Catching Art Forgers with Chemistry
How scientists test whether a painting is genuine: anachronistic pigments like titanium white and Prussian blue, X-ray fluorescence, Raman and infrared spectroscopy, X-radiography, lead isotopes, radiocarbon dating of canvas and the 'bomb peak'.
The Beer–Lambert Law with Worked Examples
How absorbance depends on concentration, path length and molar absorptivity: A = εcl explained, absorbance vs transmittance, six worked examples, why the law fails at high concentration, and how it's used.
Beer–Lambert Law Practice Problems
Seventeen worked Beer–Lambert practice problems: absorbance and transmittance conversions, finding concentration, molar absorptivity and path length, calibration graphs, dilution factors, mixtures, choosing a wavelength and spotting when the law breaks down.
Boiling Point Determination
How to measure the boiling point of a liquid in the lab: the distillation method, the Siwoloboff micro method with an inverted capillary, what boiling actually is, correcting for atmospheric pressure, what boiling points say about purity, and common mistakes.
Calculating Percentage Uncertainty
How to find absolute and percentage uncertainty for balances, thermometers, pipettes and burettes, how to combine uncertainties in a calculation, and how to compare your result with an accepted value, with worked examples.
Making and Using a Calibration Curve
How to make a calibration curve to measure concentration: preparing standards by serial dilution, measuring a signal, plotting and fitting the line, reading off unknowns, linear range, blanks and checking reliability.
Chemical Storage and Incompatible Chemicals
Why chemicals can't simply be stored alphabetically: incompatible groups such as acids and bases, oxidisers and flammables, water-reactive metals and cyanides with acids; segregation by hazard class, flammables cabinets, labelling, shelf life, peroxide-forming solvents and stock control.
Colorimetry: Measuring Concentration by Colour
A practical guide to colorimetry: how a colorimeter works, choosing a complementary filter, making standards, zeroing with a blank, plotting a calibration curve and finding an unknown concentration, with sample results.
How Drug Tests Work: Immunoassays and GC-MS
The chemistry behind workplace, sports and roadside drug tests: why labs look for metabolites, how antibody-based immunoassay screens work, cut-off levels, false positives, and why every positive screen is confirmed by GC-MS or LC-MS/MS.
Gel Electrophoresis: Separating DNA and Proteins
How gel electrophoresis separates molecules by size and charge in an electric field: why DNA moves towards the positive electrode, agarose vs polyacrylamide gels, DNA ladders, SDS-PAGE for proteins, staining, reading a gel, and uses in forensics, medicine and research.
Experimental Design Practice Questions
Fourteen practice questions on planning chemistry investigations: identifying variables, writing hypotheses, choosing equipment and ranges, control experiments, repeatability, spotting flaws in a method, and suggesting specific improvements, with model answers.
Random vs Systematic Errors
The difference between random and systematic errors in chemistry experiments, how each affects accuracy and precision, how to spot them in data, how to reduce them, and how to write about them in an evaluation.
How Food Is Analysed: Labels, Additives and Contaminants
Where the numbers on a nutrition label come from: measuring water, protein by the Kjeldahl and Dumas methods, fat by solvent extraction, carbohydrate by difference, energy, salt, vitamins, additives, contaminants like mycotoxins and pesticides, and food fraud testing.
Analysing Food Dyes with a Colorimeter
A complete practical to measure the concentration of a food dye in a sports drink or sweet coating using a colorimeter: choosing the wavelength, preparing standards by dilution, drawing a calibration graph, calculating the result, sample data, errors and evaluation.
Gravimetric Analysis with Worked Examples
How gravimetric analysis measures an amount by weighing a pure product: precipitation and volatilisation methods, the steps from precipitating to heating to constant mass, and five fully worked calculations.
Identifying Ions: A Qualitative Analysis Flowchart
A practical, step-by-step scheme for identifying the cation and anion in an unknown salt: flame tests, sodium hydroxide and ammonia precipitates, the ammonium test, and tests for carbonate, sulfate, halides and nitrate, in the right order.
How Chemists Identify an Unknown Compound
A step-by-step strategy for identifying an unknown substance: observation, purity checks, elemental analysis, molecular formula from mass spectrometry, functional groups from IR, structure from NMR, and a fully worked example.
Infrared Spectroscopy: How Molecules Vibrate
How infrared spectroscopy identifies functional groups: bond vibrations, wavenumbers, a table of key absorptions, reading an IR spectrum step by step, the fingerprint region, and uses from breathalysers to climate science.
Famous Lab Accidents and the Safety Lessons They Taught
Real laboratory accidents, from Robert Bunsen's arsenic explosion to modern university incidents with dimethylmercury, tert-butyllithium and scaled-up energetic compounds, told respectfully and each paired with the safety lesson that changed practice.
Mass Spectrometry: How It Works
How a mass spectrometer ionises, accelerates, separates and detects particles by mass-to-charge ratio, how to read a mass spectrum, calculating relative atomic mass, the molecular ion, fragmentation and real-world uses.
Reading Mass Spectra for Elements and Isotopes
Worked examples on mass spectra of elements: identifying isotopes, calculating relative atomic mass from percentages and relative intensities, finding unknown abundances, and interpreting diatomic molecules like Cl₂ and Br₂.
Melting Point Determination
A practical lab guide to measuring melting points with a capillary tube and melting point apparatus: preparing the sample, heating rates, reading the range, what a broad or low range tells you about purity, mixed melting points, calibration and common errors.
Microscale Chemistry: Small Experiments, Big Learning
A teacher's guide to microscale chemistry: what it is, why it improves safety, cost, speed and learning, the basic kit (well plates, dropper bottles, plastic pipettes, Petri dishes), five classic microscale experiments, and practical tips for introducing it in your classroom.
Qualitative Analysis Practice Questions
Twenty practice questions on identifying ions and compounds, from single flame tests to multi-step unknowns, each with a full worked answer explaining the reasoning, the equations and the common traps.
How to Write a Risk Assessment for a Chemistry Practical
A step-by-step guide to writing a risk assessment for a chemistry experiment: identifying hazards, assessing risks, choosing control measures, emergency actions and disposal, with a completed example for a titration.