QCE Chemistry IA2 student experiment template: the 2026 guide

What this guide is for

The QCE Chemistry IA2 student experiment is a major assessment. This guide covers the scientific report structure, marking criteria, common contexts, and the writing moves that distinguish top-band from middle-band reports.

Marking criteria

QCAA publishes detailed marking criteria. The major categories:

1. Research and planning. Quality of research question, hypothesis, methodology.
2. Analysis of evidence. Data analysis, uncertainty, graphical representation.
3. Interpretation and evaluation. Discussion of results, uncertainty sources, limitations.
4. Conclusion. Direct answer to the research question.

Top band requires excellence in all four.

Scientific report structure

Title. Specific and descriptive.

Abstract. Around 150 words. The question, methodology, key result, conclusion.

Introduction.

• Research question (specific, testable).
• Theoretical framework (relevant Unit 3 theory).
• Hypothesis (with prediction).
• Aim.

Method.

• Variables (independent, dependent, controlled).
• Apparatus (labelled diagram).
• Procedure (step-by-step, detailed).
• Risk assessment.

Results.

• Raw data table with units and uncertainties.
• Processed data table with units and propagated uncertainties.
• Graph(s) with uncertainty bars.

Analysis.

• Calculations (with uncertainties).
• Best-fit line; gradient and intercept with uncertainty.
• Comparison to theoretical predictions.

Discussion.

• Uncertainty sources (random and systematic).
• Limitations of the investigation.
• Suggested improvements.
• Implications.

Conclusion. Direct answer to research question with experimental result and uncertainty.

References.

Three common contexts

Equilibrium (Topic 1)

Investigate the effect of concentration or temperature on the position of equilibrium for a specified reaction.

Common system: iron(III) thiocyanate.

IMATH_0
The complex is deep red; allows colorimetric monitoring. Add Fe$^{3+}$ or SCN$^-$ to shift equilibrium; observe colour change.

Titration (Topic 1)

Determine the concentration of an acid or base in a sample using standardised reagent.

Common: vinegar (ethanoic acid). Titrate with standardised NaOH. Use phenolphthalein indicator. The mass percentage of ethanoic acid in commercial vinegar is around 5%.

Galvanic cell (Topic 2)

Construct a galvanic cell and measure its potential; compare to the theoretical value from standard reduction potentials.

Common: Zn/Cu cell. Theoretical $E^0_{cell} = +1.10$ V. Compare measured potential to theoretical; account for any deviation.

Research question

Must be specific. Example weak: "How does temperature affect the iron(III) thiocyanate equilibrium?"

Example strong: "How does temperature (in the range 10 to 60 degrees C in 10-degree intervals, with a tolerance of plus/minus 0.5 degrees C) affect the equilibrium concentration of FeSCN$^{2+}$ (measured via UV-visible absorbance) in a system with initial concentrations of 0.10 M Fe(NO3)3 and 0.10 M KSCN?"

The strong version specifies ranges, increments, tolerances, and measurement methods.

Uncertainty handling

Random uncertainty. From repeated measurements (typically 3-5 trials). Estimate by half-range or standard deviation.

Systematic uncertainty. From instrument bias (zero offset, calibration). Estimate from instrument specifications.

Instrumental uncertainty. Half the precision (typically).

Propagation.

• Addition/subtraction: add absolute uncertainties.
• Multiplication/division: add fractional uncertainties.
• Powers: multiply fractional uncertainty by the power.

Reporting. Value plus/minus uncertainty, consistent decimal places.

Linearisation and gradient

For a non-linear relationship, linearise before plotting.

Example. For a titration to determine Ka, plot pH vs log([A$^-$]/[HA]); the intercept is pKa.

Gradient uncertainty: max-slope line and min-slope line through error bars; half-range of the two slopes is the gradient uncertainty.

Discussion

Strong discussions:

Uncertainty sources. Name specific sources tied to specific experimental steps. Random (variation in burette readings) vs systematic (calibration error). Major contribution vs minor.

Limitations. What the investigation cannot conclude. Are controlled variables truly held constant? Is the range of the IV sufficient? Are the trials enough?

Improvements. Specific changes that would reduce uncertainty or extend the result. Use longer pendulum; use more trials; use better instrument.

Common errors

Research question too broad. Specify ranges and tolerances.

Insufficient data points. Use at least 5 across the IV range, with 3-5 trials per point.

No uncertainty propagation. Every numerical result should have uncertainty.

Limitations as decoration. Each limitation must be argued; "human error" without specificity is meaningless.

Conclusion without answer. Always state the experimental result and compare to expectations explicitly.

In one sentence

The QCE Chemistry IA2 student experiment is a 2000-word scientific report on a student-designed Unit 3 investigation (common contexts: equilibrium effects, acid-base titrations, galvanic cells); top-band reports demonstrate a specific testable research question, systematic uncertainty handling (random and systematic, propagated through calculations), linearisation where applicable, gradient extraction with min/max line method, and a discussion that names uncertainty sources tied to specific experimental steps with suggested improvements.