Basic Rubric for Assessing Chemistry Lab Reports (Total: 100 points)
How to use:
- Score each criterion using the point values and descriptors.
- Apply the performance levels consistently across reports.
- Provide brief, actionable comments tied to specific criteria.
Performance levels (apply to each criterion):
- Exemplary: Fully correct, complete, precise, and well-justified; no substantive omissions.
- Proficient: Mostly correct and complete; minor gaps that do not alter conclusions.
- Developing: Partially correct; noticeable gaps or errors that weaken conclusions.
- Beginning: Major omissions, errors, or unclear writing that undermine validity.
1) Title and Abstract (5 points)
- Include a precise, informative title reflecting the main variable(s) or compound(s).
- Write a concise abstract (100–150 words) stating objective, brief method, key quantitative results (with units and uncertainty), and main conclusion.
- Avoid undefined acronyms and procedural details.
2) Purpose and Background/Theory (10 points)
- State a clear objective or research question and, if applicable, a testable hypothesis.
- Summarize the relevant chemical principles, reactions (with balanced equations), and key equations used.
- Define variables and terms; explain why the method is appropriate.
- Cite at least one credible source for theory or literature values.
3) Safety, Hazards, and Waste (5 points)
- Identify hazards for reagents and operations (e.g., corrosive, flammable, toxic).
- Specify PPE and engineering controls (e.g., goggles, gloves, fume hood).
- State correct waste segregation/disposal and spill response.
- Note any special handling (e.g., drying agents, pressurized gases).
4) Materials and Methods (10 points)
- Provide enough detail for reproducibility: reagent identities and concentrations, quantities, glassware and instrument models/settings where relevant.
- Describe controls, controlled variables, and calibration steps.
- Note deviations from the given procedure and justify them.
- Use past tense, passive or active voice consistently; avoid cookbook lists without explanation of purpose.
5) Data and Observations (15 points)
- Present raw data clearly in well-labeled tables with units and correct significant figures.
- Include qualitative observations (color changes, precipitate formation, gas evolution, temperature changes).
- Record instrument uncertainty/resolution and conditions (temperature, pressure if relevant).
- Show calibration records or standardization data when applicable.
- Do not retroactively alter raw data; flag and justify any excluded data points.
6) Data Analysis and Calculations (20 points)
- Show a sample calculation for each type (with formulas, substitutions, units, and significant figures).
- Propagate uncertainty appropriately (instrumental, statistical); report mean, standard deviation, and number of trials.
- Use appropriate models: linear, non-linear, or stoichiometric as justified by theory; justify any linearization.
- Graph correctly: titled axes with quantities and units, labeled data series, trendline/fit with parameters and goodness-of-fit (e.g., R²) when applicable; avoid plotting derived from averaged raw data if individual points are relevant.
- Compute percent yield, percent error, or recovery when applicable; compare to literature values with citations.
7) Results (10 points)
- Report final values with units and uncertainty (or confidence interval) at appropriate significant figures.
- Present results clearly (text plus a concise table or figure as needed); avoid re-stating raw data.
- Compare to literature/accepted values and state the magnitude and direction of any deviation.
8) Discussion and Error Analysis (15 points)
- Interpret results using chemical principles; explain trends and mechanisms where relevant.
- Distinguish random versus systematic errors; link each to its effect (direction and magnitude) on the result.
- Evaluate assumptions and limitations of the method and measurements.
- Propose specific, feasible improvements and follow-up experiments or controls.
- Address discrepancies without speculating beyond evidence.
9) Conclusion (5 points)
- Give a concise answer to the objective; state whether data support the hypothesis.
- Reiterate key quantitative findings (with uncertainty) and their significance.
- Avoid introducing new data or analysis.
10) References, Presentation, and Mechanics (5 points)
- Cite sources consistently in a recognized style; include in-text citations and a reference list.
- Number and caption figures/tables; refer to each in text.
- Ensure clear, concise writing; correct grammar and spelling; logical organization with section headings.
- Adhere to any provided format guidelines; maintain academic integrity (original data, proper attribution).
Quick scoring guide (optional weighting guidance):
- Intro/general chemistry: place more weight on safety, data recording, and basic calculations (e.g., 3, 10, 7, 10, 20, 20, 8, 12, 5, 5).
- Analytical/physical chemistry: place more weight on uncertainty, modeling, and discussion (as listed above).
Instructor feedback checklist (use to justify points and guide revisions):
- Objective stated and aligned with methods.
- Hazards and waste addressed accurately.
- Raw data complete, with units and uncertainties.
- Calculations transparent; units tracked; significant figures correct.
- Graphs properly formatted and models justified.
- Uncertainty propagated and reported with results.
- Discussion links data to chemistry concepts; errors analyzed with direction/magnitude.
- Conclusions concise and defensible.
- Sources cited; academic honesty maintained.
Common pitfalls to flag:
- Missing units or inconsistent significant figures.
- Reporting averages without showing spread (SD) or number of trials.
- Using R² alone to claim model validity without residual analysis or theoretical justification.
- Vague “human error” statements without mechanism or impact.
- Unsafe or incorrect waste disposal statements.
- Copy-pasted procedures without noting deviations or calibrations.
Scoring tip:
- Deduct proportionally for missing uncertainty in quantitative results.
- Require at least one worked sample calculation per calculation type.
- For non-quantitative labs, shift points from Analysis to Discussion while still requiring clear evidence and reasoning.
