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Chemistry IA2 Student Experiment Guide
A QCAA-informed guide to writing a stronger QCE Chemistry IA2 student experiment, from research question to processed data, limitations and improvements.
Updated 2026-05-13 ยท 3 min read
Chemistry IA2 student experiment guide
Chemistry IA2 is the student experiment. It asks you to modify, refine, extend or redirect a practical investigation from Unit 3, collect primary data, process it, and make a justified conclusion.
The biggest mistake is treating IA2 like a normal prac report. It is not just "what we did in class". It needs to show why your version of the experiment is valid, what your data proves, and where the evidence is still limited.
Start with a question that can actually be answered
A useful Chemistry IA2 research question names:
- the chemical system being tested
- the independent variable
- the dependent variable
- the conditions that keep the question narrow enough to answer
For example, a question about electrolyte concentration and cell potential is easier to evaluate than a broad question about "factors affecting electrochemical cells". The narrower question gives you a clear graph, clearer controls, and a conclusion that can be judged.
Make the modification matter
QCAA sample IA2 materials describe the task as modifying an experiment relevant to Unit 3 subject matter. Your modification should not feel random.
A strong modification might:
- change the range of concentrations, temperatures, surface areas or masses tested
- compare a controlled set of materials or reactants
- improve a measurement method
- redirect the practical toward a more specific relationship
Explain why the modification is useful. If the modification does not create better evidence for the research question, it will be hard to justify.
Process data before you interpret it
Raw measurements rarely prove enough by themselves. Depending on the topic, you may need:
- mean values from repeat trials
- percentage uncertainty or absolute uncertainty
- rates, gradients, percentage change or calculated values
- a graph with labelled axes, units and a suitable line or curve
- discussion of anomalies before using them in conclusions
The result section should make the trend visible before the discussion explains it chemically.
Use chemistry in the discussion
The discussion should connect the data to Chemistry concepts. If you are writing about reaction rate, explain collisions, activation energy, concentration or temperature. If you are writing about electrochemistry, explain redox behaviour, electrodes, ion movement and cell potential. If you are writing about equilibrium, explain the system response using equilibrium principles.
Avoid a conclusion that only says "the trend increased". The marker needs to see why the trend happened.
Evaluate limitations properly
"Human error" is too vague. A better limitation names the specific measurement or design problem, explains how it affected reliability, validity or accuracy, and then proposes a matching improvement.
Better examples:
- concentration changes during the experiment because evaporation changed solution volume
- temperature was not controlled, changing reaction rate across trials
- the measuring instrument resolution was too low for the size of the change being measured
- the chosen concentration range was too narrow to show whether the relationship stayed linear
The improvement should fix the limitation you just identified. Do not list generic improvements that have no connection to the data.
IA2 checklist before submission
- Does the research question name the variables and chemical system?
- Is the modification justified, not just described?
- Are raw and processed data both included clearly?
- Are graphs labelled with units and appropriate precision?
- Does the discussion explain the trend using Chemistry?
- Does the conclusion answer the research question directly?
- Do limitations explain the effect on evidence quality?
- Do improvements follow logically from limitations?