Why concentration and context matter
By the end of this lesson
- Distinguish stock and final concentration
- Attach chemical identity and units to values
- Preserve evidence and preparation context
See it
A concentration only has meaning when the chemical identity, units, stock preparation, final volume, plant material, stage, and protocol are known. A small unit error can change the intended treatment by orders of magnitude.
Understand it
Distinguish stock and final concentration
Always pair a value with a unit.
A bare number cannot tell whether the writer means mass, stock volume or final concentration.
Attach chemical identity and units to values
Separate stock concentration from final-medium concentration.
A concentrated stock and the resulting treatment medium describe different solutions and cannot share an unexplained value.
Preserve evidence and preparation context
Record whether a value came from a canonical source, local variation, or experiment.
Ambiguous quantities need source clarification; guessing would create an untraceable treatment.
Worked example
A note says '2 BAP' but omits the unit, stock concentration and final volume. It cannot specify a reproducible treatment. Retrieve the actual source instead of guessing whether it describes mass, concentration or a stock volume.
Explain your decision before opening the worked reasoning below.
Show the worked reasoning
Values become interpretable when preparation definitions and the intended plant/stage are preserved.
Evidence provenance and versioning keep a local experiment from silently replacing a reviewed source treatment.
A naked number such as ‘2 BAP’ is not a usable scientific instruction.
Try it
What should be done with the example's incomplete note?
Use the worked example above to explain your answer in your own words before taking the quiz.
Lesson quiz
Assessment version: 2026-10-15-v2. Previous reading-completion markers are retained. This revised quiz has its own result.
Apply it
Use the worked example to write a short decision record: what did you observe, which rule did you apply, and what would you check before acting?
Completion marks reading progress, not a quiz pass or professional certification.