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Carry units through every calculation so mistakes become visible before they reach the lab bench. Practice SI prefixes, derived units, unit cancellation, and conversions such as µL to mL, ng to g, and mm² to m².
Pick the right tool for measuring mass or volume, then read it in a way that matches its limits. Reason through tare, meniscus, micropipette ranges, volumetric glassware, balance readability, and why the last digit is usually uncertain.
Turn an amount of material into a usable concentration and back again. Work with molarity, molar mass, mass/volume units, percent solutions, ppm, and common bioengineering shorthand such as 1X and mg/mL.
Apply the previous explanations in a guided problem.
Plan single and serial dilutions without guessing. Use C1V1 = C2V2, dilution factors, fold changes, and final-volume thinking to make a target concentration from a stock solution.
Connect pH to hydrogen ion concentration and use the logarithmic scale correctly. Choose and reason about buffers with pKa, buffer range, and the Henderson-Hasselbalch relationship without treating pH as a normal linear number.
Check your understanding with a short quiz.
Distinguish accuracy, precision, bias, resolution, and repeatability when judging a measurement. Decide whether a problem comes from random scatter, a systematic offset, instrument limits, or careless reporting.
Report calculated results with uncertainty that matches the measurements behind them. Propagate uncertainty through simple sums, differences, products, quotients, and averages, and use significant figures as a reporting rule rather than a substitute for uncertainty.
Use blanks, standards, and calibration curves to turn instrument signals into trustworthy values. Identify the linear range, interpolate unknowns, notice saturation or drift, and read slope, intercept, residuals, and R² without overtrusting a pretty line.
Choose error bars that match the question being asked. Compare technical and biological replicates, standard deviation, standard error of the mean, and confidence intervals so a plotted measurement communicates variability honestly.
Review this chapter with practice based on your mistakes.
