IB Chemistry SL Internal Assessment Example

Consider embedding a brief context descriptor in the title or subtitle (e.g., mention of national sanctions or environmental motivations) to anchor readers immediately in the study’s relevance.

The title is concise and clearly indicates the investigation’s focus on feedstock variation and biodiesel yield, providing a strong initial framing.

The introduction situates the research within national fuel sanctions and global environmental concerns, demonstrating clear contextual motivation.

Tighten the explicit connection between historical oil sanctions and the chosen laboratory transesterification protocol to reinforce the study’s rationale.

The research question is explicitly stated with reference to multiple feedstocks and yield measurement, reflecting specific and appropriate context.

To strengthen methodological considerations, explicitly plan for replicates and discuss their role in quantifying random uncertainties.

The dependent variable is precisely defined with a clear LaTeX equation and measurement uncertainty acknowledged.

Under control variables, specify the methanol-to-oil molar ratio and the NaOH concentration to ensure data sufficiency and reproducibility.

In the procedure, clarify sentences truncated by line breaks (e.g., “On a …”) to avoid ambiguity and ensure full reproducibility.

The chemicals list is exhaustive, including sample masses and reagent purities, which supports reproducibility.

Specify stirring speed (e.g., rpm) and magnetic mixer settings to allow precise experiment replication.

The risk assessment table is detailed with clear hazard–precaution mappings and appropriate risk levels.

The mechanism of transesterification and choice of NaOH catalyst are clearly explained and visually supported by Figure 2.

Equation 1 for percentage yield is presented clearly in LaTeX, aiding precise communication of the calculation.

Replace vague quantities like “about 100 g” with the exact measured masses to reduce systematic error.

Raw data are presented in a clearly labelled table with appropriate units, facilitating unambiguous interpretation.

Include the calculated uncertainty margins alongside the yield percentages in Table 2 to improve clarity of data precision.

Error bars are described in the text but not shown in Figure 3; plot them to visually represent uncertainty.

The claim that results “are close to previous experimental values” would be stronger with specific numerical comparisons to cited references.

The uncertainty propagation formula is correct, but the final numerical result and significant figures should be re-checked for arithmetic accuracy.

The conclusion recaps findings well but omits discussion of measurement uncertainties and their influence on data interpretation.

Enhance the conclusion by explicitly comparing the experimental yields to literature thresholds (e.g., ≥90 %) and discussing statistical significance.

Linking yield differences to fatty acid profiles demonstrates a solid comparison against scientific context and supports the conclusion.

The evaluation identifies specific methodological weaknesses and discusses their likely effects on precision and accuracy.

Rank the methodological limitations by their relative impact on the results (e.g., layer separation vs. catalyst dissolution) to deepen the evaluation.

Outline feasibility considerations (cost, equipment availability) when describing improvements to show practical implementation potential.