IB Chemistry SL Internal Assessment Exemplar
The effect of changing the sugar concentration (25%, 17%, 13%, 8%, 4%, 0%) on the pressure of carbonated water.
Overall Score: 16/24
IB Grade: 5
Was this exemplar helpful?
General feedback
16/24
0
12
24
5.1·weakness
Page 6
Procedure numbering is inconsistent (two steps labelled “2.”). Revise list structure to avoid confusion during reproduction.
5.2·strength
Page 11
Strong use of multiple trials improves data reliability and demonstrates rigorous approach to addressing experimental variability.
Criteria A: Research Design
6/6
0
3
6
Criteria Strands
Excellent
Research question context
Good
Methodological considerations
Good
Methodology description
Criteria Feedback
- Research question framed in a specific, authentic context linking soda consumption statistics to chemical equilibrium.
- Explicit connection of relevant theory (Henry’s law, crowding, Le Chatelier) to chosen variables.
- Comprehensive identification of independent, dependent and controlled variables with rationale.
- Methodology is detailed enough to allow full reproduction with clear procedures, equipment lists and calculations.
- No citation of industry pressures to strengthen commercial relevance.
- Justification for choice of 40 °C bath and 5 min collection time is only stated, not fully explained.
- Materials list omits grade/purity of reagents and supplier details.
- Procedural ambiguity around simultaneous sensor use and cork insertion timing remains.
Criteria B: Data Analysis
4/6
0
3
6
Criteria Strands
Good
Communication of data recording and processing
Moderate
Consideration of uncertainties
Good
Data processing quality
Criteria Feedback
- Data tables are clearly structured with units, uncertainties and triplicate trials.
- A well-labelled scatter graph with trendline and R² is provided.
- Averaging of triplicate rates and calculation of uncertainties are correctly executed.
- Data processing is internally consistent and mostly accurate.
- Inconsistent significant figures and a typographical error in concentration labels reduce precision.
- Propagation of the ±4 kPa sensor error into rate uncertainties is omitted.
- Formatting inconsistencies (e.g. notation in mixture-preparation table) affect clarity.
- Error bars are not included to display uncertainties on the graph.
Criteria C: Conclusion
3/6
0
3
6
Criteria Strands
Moderate
Conclusion relevance and support
Moderate
Scientific context comparison
Criteria Feedback
- Conclusion explicitly links the observed trend (rate decrease with sugar concentration) to the plotted data.
- Scientific theory (crowding, viscosity, Henry’s law) is referenced to rationalize results.
- Conclusion overstates linearity despite R² = 0.65 and acknowledged weak correlation.
- Contradictory statements about hypothesis support undermine consistency.
- No quantitative comparison to literature or models limits scientific context depth.
Criteria D: Evaluation
3/6
0
3
6
Criteria Strands
Moderate
Methodological weaknesses
Poor
Suggested improvements
Criteria Feedback
- Identifies specific methodological weaknesses (bubbles, parallax error, timing inconsistencies).
- Suggests realistic improvements to maintain constant conditions and address timing and bubble issues.
- Does not rank the relative impact of each limitation.
- Suggestions lack detailed explanation of how they would mitigate the identified weaknesses.
- Evaluation remains qualitative without assessing the magnitude or direction of each error’s effect.