The best IB Chemistry IA ideas are not necessarily unusual. They produce reliable quantitative data, involve chemistry you can explain, fit your laboratory resources, and leave room for meaningful analysis and evaluation. The 50 ideas below are grouped by theme, with a manipulable independent variable and a measurable dependent variable for each.
Under the current course, first assessed in 2025, the Chemistry IA is officially called the scientific investigation. It is worth 20% of the final grade, is allocated approximately 10 hours, and results in an individual report with a maximum of 3,000 words. Before selecting any idea, obtain teacher approval and complete a risk assessment based on the actual chemicals, concentrations, apparatus, and disposal procedures involved.
What makes a Chemistry IA idea workable?
A workable investigation usually has:
- One clearly defined independent variable with at least five sensible values
- A quantitative dependent variable measured with suitable precision
- Important controlled variables that can realistically be kept constant
- Enough repeated measurements to identify uncertainty and random variation
- A chemical model, equation, or theory against which results can be interpreted
- Safe, affordable materials available in a school laboratory
The current assessment uses four criteria: Research design, Data analysis, Conclusion, and Evaluation, each worth 6 marks. Novelty is not a separate criterion. A familiar reaction investigated carefully is generally stronger than an ambitious synthesis that produces limited or unreliable data.
The official IB Chemistry subject brief describes the investigation as an open-ended task in which students gather and analyse data to answer their own research question. RevisionDojo's IB Chemistry IA guide provides a practical breakdown of the current criteria.
Kinetics IA ideas
Kinetics investigations work well because rate can be measured in several ways, including gas volume, mass loss, absorbance, conductivity, or the time required to reach a fixed endpoint.
| # | Investigation idea | Independent variable | Measurable dependent variable |
|---|---|---|---|
| 1 | Reaction between magnesium and dilute hydrochloric acid | Acid concentration | Initial hydrogen production rate in cm³ s⁻¹ |
| 2 | Sodium thiosulfate and acid disappearing-cross reaction | Thiosulfate concentration | Time to obscure the cross, converted to relative rate |
| 3 | Catalytic decomposition of hydrogen peroxide | Potassium iodide concentration | Initial oxygen production rate |
| 4 | Temperature dependence of an iodine clock reaction | Reaction temperature | Time to fixed colour change or calculated rate constant |
| 5 | Effect of particle size on calcium carbonate reacting with acid | Mean particle size or surface-area category | Carbon dioxide production rate |
| 6 | Catalase-catalysed decomposition of hydrogen peroxide | Hydrogen peroxide concentration | Initial oxygen production rate |
| 7 | Vitamin C degradation during storage | Storage temperature | Ascorbic acid concentration remaining after fixed time |
| 8 | Fading of a food dye under illumination | Distance from a fixed light source | Change in absorbance per minute |
| 9 | Crystal violet reaction with hydroxide ions | Hydroxide concentration | Rate constant calculated from absorbance-time data |
Ideas 3 and 6 require low peroxide concentrations and eye protection. For idea 8, use a cool LED source rather than a hot lamp, and control wavelength, solution depth, and exposure time.
Acids and bases IA ideas
Acid-base projects are accessible, but simply measuring the pH of different products is usually too descriptive. A stronger investigation tests a continuous variable and calculates concentration, equilibrium behaviour, or buffer capacity.
| # | Investigation idea | Independent variable | Measurable dependent variable |
|---|---|---|---|
| 10 | Temperature and the acid dissociation of ethanoic acid | Temperature | Calculated acid dissociation constant, Ka |
| 11 | Dilution and percentage ionization of a weak acid | Analytical acid concentration | Percentage ionization from measured pH |
| 12 | Composition of an ethanoic acid/ethanoate buffer | Acid-to-conjugate-base mole ratio | Buffer pH |
| 13 | Buffer composition and resistance to added acid | Buffer component ratio | Moles of HCl required for a fixed pH change |
| 14 | Antacid neutralizing capacity | Antacid mass or formulation | Moles of acid neutralized by back titration |
| 15 | Temperature and titratable acidity of fruit juice | Juice temperature before analysis | Total titratable acidity |
| 16 | Carbonation loss from sparkling water | Degassing time | Total acidity or pH under standardized conditions |
| 17 | Acid concentration and calcium carbonate solubility | Initial acid concentration | Mass or moles of carbonate dissolved |
| 18 | Ionic strength and apparent weak-acid dissociation | Sodium chloride concentration | Apparent Ka calculated from pH |
Use calibrated pH probes where possible. Temperature-dependent investigations need enough equilibration time and should distinguish a genuine equilibrium effect from temperature-related probe response.
Energetics IA ideas
Energetics projects should emphasize energy transfer, heat capacity, and uncertainty. Open-flame combustion often loses substantial heat and introduces avoidable fire risks, so solution calorimetry is usually more reliable.
| # | Investigation idea | Independent variable | Measurable dependent variable |
|---|---|---|---|
| 19 | Enthalpy of neutralization at different concentrations | Acid and base concentration | Experimental molar enthalpy change |
| 20 | Chain length and enthalpy of solution of alcohols | Number of carbon atoms in the alcohol | Molar enthalpy of solution |
| 21 | Cation identity and enthalpy of solution of chloride salts | Metal cation | Molar enthalpy of solution |
| 22 | Hydration state and enthalpy of solution | Hydration state of a suitable salt | Molar enthalpy change |
| 23 | Water volume and measured calorimetric heat loss | Volume of water or solution | Percentage deviation from accepted enthalpy |
| 24 | Calorimeter insulation thickness | Number or thickness of insulation layers | Cooling constant or corrected temperature change |
| 25 | Acid identity and carbonate reaction enthalpy | Selected dilute acid | Molar enthalpy of reaction |
| 26 | Reactant temperature and measured neutralization enthalpy | Initial reactant temperature | Experimental molar enthalpy change |
Ideas 23 and 24 investigate the measurement system itself. They can succeed if the research question remains chemically focused and the analysis explains heat exchange rather than merely ranking cup designs.
Electrochemistry IA ideas
Electrochemical investigations connect redox chemistry with quantitative models such as the Nernst equation and Faraday's laws. Clean electrodes consistently and use fresh solutions to reduce drift.
| # | Investigation idea | Independent variable | Measurable dependent variable |
|---|---|---|---|
| 27 | Ion concentration in a zinc-copper voltaic cell | Zinc or copper ion concentration | Cell potential |
| 28 | Temperature and voltaic-cell potential | Electrolyte temperature | Cell potential after equilibration |
| 29 | Salt-bridge concentration and cell performance | Inert electrolyte concentration | Initial potential or voltage decay under fixed load |
| 30 | Electrode surface area during electrolysis | Immersed electrode area | Mass deposited in a fixed time |
| 31 | Current and copper electroplating efficiency | Applied current | Percentage current efficiency from deposited mass |
| 32 | Electrolysis time and deposited copper mass | Electrolysis duration | Cathode mass increase |
| 33 | Electrolyte concentration and solution conductivity | Ionic concentration | Conductivity |
| 34 | Chloride concentration and corrosion of iron | Sodium chloride concentration | Iron mass loss per unit area and time |
Corrosion experiments require sufficient time and careful removal of corrosion products using one standardized procedure. Electrolysis should use low-voltage school equipment, with electrode products checked during the risk assessment.
Organic chemistry IA ideas
Organic topics do not need to involve complicated synthesis. Hydrolysis, oxidation, solubility, partitioning, and functional-group analysis can generate stronger data with fewer hazards.
| # | Investigation idea | Independent variable | Measurable dependent variable |
|---|---|---|---|
| 35 | Temperature and aspirin hydrolysis | Incubation temperature | Aspirin remaining or salicylate absorbance after fixed time |
| 36 | pH and aspirin hydrolysis | Buffer pH | Hydrolysis rate or percentage aspirin remaining |
| 37 | Alcohol chain length and esterification equilibrium | Identity or carbon-chain length of alcohol | Equilibrium ester yield |
| 38 | Reaction time and ester yield | Heating time in a thermostated bath | Purified ester yield |
| 39 | Solvent composition and food-dye extraction | Ethanol-water percentage | Partitioning measured by absorbance |
| 40 | Temperature and vitamin C degradation | Storage temperature | Ascorbic acid concentration by redox titration |
| 41 | Light exposure and oil oxidation | Illumination duration | Peroxide value or another teacher-approved oxidation measure |
| 42 | Carbon-chain length and alcohol-water miscibility | Number of carbon atoms | Saturation concentration or phase-separation composition |
Avoid hazardous extraction solvents such as benzene, chloroform, or diethyl ether. For esterification, use small quantities, a thermostated water bath, suitable ventilation, and a teacher-approved procedure.
Environmental chemistry IA ideas
Environmental investigations need controlled samples. Unstandardized field samples may vary in several ways at once, making cause-and-effect conclusions difficult.
| # | Investigation idea | Independent variable | Measurable dependent variable |
|---|---|---|---|
| 43 | Activated carbon mass and dye removal from water | Mass of activated carbon | Percentage decrease in dye absorbance |
| 44 | Contact time and adsorption by activated carbon | Adsorption time | Dye concentration remaining |
| 45 | Solution pH and adsorption of a food dye | Initial pH | Adsorption capacity in mg g⁻¹ |
| 46 | Water hardness and soap effectiveness | Calcium ion concentration | Soap volume required to form persistent lather |
| 47 | Heating and temporary water hardness | Boiling or heating duration | Calcium carbonate equivalent by titration |
| 48 | Soil-carbonate content and acid neutralization | Mass fraction of carbonate in simulated soil | Moles of acid neutralized |
| 49 | Salinity and dissolved oxygen | Sodium chloride concentration | Dissolved oxygen concentration using a probe |
| 50 | pH and phosphate removal by a safe adsorbent | Initial pH | Phosphate concentration remaining using a test kit or colorimeter |
Use simulated water or soil systems when possible because they allow one variable to be changed while composition remains controlled. Environmentally themed work should also minimize reagent volumes and include an appropriate waste-disposal plan.
How to turn an idea into a focused research question
An idea is only a starting point. A useful structure is:
How does [independent variable with range and units] affect [quantitative dependent variable and measurement method] in [defined chemical system] under [important controlled conditions]?
For example, idea 27 could become: “How does zinc sulfate concentration from 0.10 to 1.00 mol dm⁻³ affect the open-circuit potential of a Zn/Zn²⁺ || Cu²⁺/Cu cell at 25.0°C?” This specifies the system, range, measurement, and temperature while creating a direct connection to the Nernst equation.
Before committing, run a pilot at the lowest, middle, and highest proposed values. Check that the change is measurable, the reaction is neither instantaneous nor impractically slow, and the signal is large relative to instrument uncertainty. RevisionDojo's guide to designing effective science IA experiments can help you refine variables and controls.
Common mistakes when choosing an IA topic
- Choosing categories instead of a continuous variable: Comparing five drink brands creates many uncontrolled compositional differences.
- Relying on one reading per condition: Repeats are needed to assess random variation and identify anomalies.
- Using equipment without checking its range: A colorimeter cannot distinguish samples whose absorbance is beyond its useful range.
- Treating time as the reaction rate: Rate normally requires a change in concentration, gas volume, mass, or absorbance per unit time.
- Ignoring chemical waste: “Wear goggles” is not a complete risk assessment; disposal and environmental effects also matter.
- Selecting a method before finding the chemistry: Your analysis should connect results to a model such as collision theory, equilibrium, energetics, Beer-Lambert behaviour, or electrochemical theory.
The Royal Society of Chemistry's risk-assessment guidance explains the sequence of identifying hazards, evaluating risks, and selecting controls. Final decisions must follow your school's rules and your teacher's approved risk assessment.
Planning the investigation and report
Create a proposal containing the research question, chemical rationale, variables, apparatus, method, safety controls, waste plan, and intended data processing. Decide how uncertainties will be recorded before collecting data, rather than adding them after the experiment.
The IB permits limited collaboration in appropriate cases, including shared methodologies, but each student must have a different independent or dependent variable where required, collect unique data, and submit an individual report. The official IB Chemistry curriculum update explains this change.
You can compare your structure with Chemistry IA exemplars, but an exemplar should be used to understand analytical quality rather than copied as a template. The RevisionDojo Chemistry IA grader and Jojo AI can help identify unclear variables or unsupported evaluation points, while your final decisions and writing must remain your own. Use the IB Chemistry Questionbank to strengthen the syllabus theory behind your investigation.
Conclusion
Strong IB Chemistry IA ideas prioritize feasibility, safety, measurable data, and chemical reasoning over novelty. Choose a system you can control, test it with a pilot study, and make sure the expected relationship can be analysed using appropriate chemistry. RevisionDojo's IA guide, exemplars, Chemistry Questionbank, and IA feedback tools are most useful once you have narrowed your idea to one precise, teacher-approved research question.
Sources and referenced URLs
- IB DP Chemistry subject brief, first assessment 2025
- IB Chemistry curriculum and assessment updates
- Royal Society of Chemistry risk-assessment guidance
- RevisionDojo IB Chemistry IA guide
- RevisionDojo guide to designing science IA experiments
- RevisionDojo Chemistry IA exemplars
- RevisionDojo Chemistry IA grader
- RevisionDojo IB Chemistry Questionbank