A viral video shows green algae blooms near an industrial discharge point. Inspector Chen collected a 10 ml sample. Dr Lim needs nitrate and phosphate concentrations before a press release.
Decide which method is reliable, create a calibration curve, test the unknown sample, and explain whether one measurement is enough. The simulated unknown contains both nutrients and a possible colour interference.
Drag a method into a category, or tap a method then tap a category. Use Tab and Enter or Space for keyboard placement.
Useful for quick evidence, not enough for legal concentration.
Best fit for both concentration and limited sample volume.
May confirm results, but constraints must be checked.
Use the calibration curve for each ion. Repeat readings to check consistency before making a legal decision.
The workshop activity asks students to predict how copper(II) ions might affect colorimetry. Toggle copper contamination, then compare the apparent concentration.
If phosphate is near the legal limit, 5 mg/L PO4^3- in a 5 ml sample is about 2.63 x 10^-7 mol phosphate. The method needs 23 mol NaOH per mol phosphate.