RevisionPrep FAQ
Common Mistakes in MYP Chemistry Assessments
Answered by RevisionPrep's IB Educators
What are common mistakes in MYP Chemistry assessments? Mostly, students lose marks not from wrong chemistry but from missing what each criterion actually asks for—vague conclusions, no units, copied method steps instead of analysed data. Here's what I see every year, and how to stop it happening to you.
Criterion-by-criterion mistakes
What are common mistakes in MYP Chemistry assessments?
The biggest mistake is treating all four criteria the same way. Students write good chemistry but forget Criterion C (Processing and Evaluating) wants a limitations discussion, not just a results table, and Criterion D (Reflecting on Impacts) needs real-world context, not a restated conclusion.
Common patterns I mark every year:
- Criterion A: describing the topic instead of stating a testable hypothesis with reasoning.
- Criterion B: recording a method without a labelled, repeatable procedure or risk assessment.
- Criterion C: presenting a data table with no processing (no averages, no graph, no uncertainty).
- Criterion D: a conclusion that repeats the results instead of evaluating validity and suggesting improvements.
According to the IB's MYP: Sciences guide, each criterion is marked out of 8, in strands of 2, so missing even one strand caps your score in that criterion.
why do I keep losing marks on Criterion C in chemistry?
Criterion C isn't just "show your data"—it's Processing and Evaluating. Most students lose marks because they present a table or graph with no interpretation: no trend described, no percentage error calculated, no comment on whether the data supports the hypothesis.
Quick tip: always calculate percentage error using \text{% error} = \frac{|\text{experimental} - \text{accepted}|}{\text{accepted}} \times 100 and explicitly say whether it's within acceptable range for the equipment used. A titration with a burette (±0.05 cm³) has a very different acceptable error than a measuring cylinder.
why did I lose marks even though my experiment worked?
A successful experiment and a strong assessment aren't the same thing. Markers assess your written scientific thinking, not whether your reaction actually happened. You can get a perfect precipitate and still score low if you never explain why the result supports or contradicts your hypothesis.
I tell every student I teach: the chemistry in your test tube is worth nothing on paper unless it's translated into analysis. Write the 'so what' sentence after every result—what does this number actually tell you about the reaction?
Exam technique mistakes
what mistakes do students make in MYP chemistry exams?
The most common exam mistake is misreading command terms—writing a description when the question asks you to "explain" or "justify". A close second is skipping units and significant figures in calculation answers, which loses easy method marks even when the working is correct.
Command term traps:
- "State" wants a short factual answer, no explanation needed—don't waste time.
- "Explain" needs a reason linked to a scientific concept (why, not just what).
- "Evaluate" needs strengths and weaknesses, with a judgement at the end.
Mixing these up is the single fastest way to lose marks on an otherwise correct answer.
how do I avoid losing marks on calculation questions?
Show every step, include units at every stage, and round your final answer to a sensible number of significant figures—usually matching the least precise data given. Markers award method marks for correct working even if your final number is wrong, so skipping steps costs you twice.
Worked example: Find the moles of NaOH in 25.0 cm³ of a 0.100 mol/dm³ solution.
- Convert volume:
- Apply
A student who skips step 1 and writes gets the wrong answer but still needs to show the formula was applied correctly to claim partial credit.
why do I run out of time in chemistry tests?
Running out of time almost always means you're over-answering low-mark questions. A 1-mark "state" question doesn't need three sentences. Spend roughly one minute per mark as a rule of thumb, and flag longer extended-response questions to tackle last if you're behind schedule.
Quick tip: scan the whole paper first and mark the mark allocation next to each question number. It takes thirty seconds and stops you writing an essay for a 2-mark question.
How to fix these mistakes
how can I improve my MYP chemistry grades?
Stop revising topics and start revising against the criteria descriptors themselves. Read the actual command term and strand language for Criterion A-D before your next assessment, then practise writing one paragraph per strand using past lab data or a topical worksheet.
Practising with criterion-aligned topical worksheets on RevisionPrep, checking each strand explicitly rather than just re-reading notes, is the fastest way I've seen students move from a mid-band 5 to a 7 within a term.
how do teachers actually mark MYP chemistry lab reports?
Teachers mark against the MYP Sciences criteria descriptors directly, looking for specific achievement-level language—phrases like "reasonable scientific reasoning" or "minor omissions" have exact meanings tied to mark bands. A report can be scientifically accurate and still score low if it doesn't match the strand's wording.
This is why two students with identical raw data can get very different marks—one writes to the descriptor language, one just writes chemistry.
what's the difference between a level 5-6 and a level 7-8 lab report?
A 5-6 report usually has a reasonable hypothesis and method with some gaps in analysis or evaluation. A 7-8 report explains scientific reasoning clearly, evaluates the method's validity with specific improvements, and links the conclusion back to real-world or theoretical context.
For parents
why is my child getting lower grades in chemistry than expected?
It's rarely a knowledge gap—it's usually a criterion-literacy gap. Your child may understand the chemistry perfectly but not know what Criterion C or D specifically rewards. Ask to see the actual criteria descriptors alongside a marked assessment; the pattern usually becomes obvious within one report.
Sit down with the rubric and the returned assessment together. If the same strand (e.g. evaluating limitations) is weak across multiple reports, that's the specific skill to target, not general "more revision".
how much does it cost to get extra MYP chemistry support?
Costs vary widely—private tutoring in most regions runs from roughly USD 40 to USD 100+ per hour, adding up quickly over a school year. Self-study resources like structured revision notes and topical worksheets are a lower-cost way to target the exact criteria your child is losing marks on.
| Support type | Typical cost | Best for |
|---|---|---|
| Private tutoring | USD 40-100+/hour | Personalised pace |
| School help sessions | Often free | General questions |
| Self-study resources | One-off or subscription | Targeted criterion practice |
Common Mistake vs What Actually Earns Marks
| Criterion | Common mistake | What earns marks |
| A: Inquiring | Vague research question | Testable hypothesis with reasoning |
| B: Processing | Method copied, no risk assessment | Repeatable, labelled procedure |
| C: Processing/Evaluating | Raw data, no analysis | Trends, error %, uncertainty discussed |
| D: Reflecting | Restated conclusion | Real-world link and evaluated improvements |
For criterion-by-criterion practice questions and marked worked examples, check the MYP Chemistry Revision Notes and Topical Worksheets on RevisionPrep.