Choosing the right Internal Assessment (IA) topic is often the biggest challenge IB Chemistry students face. Every year, I work with students who are capable of achieving a 6 or 7 but spend weeks struggling to find a research question that is original, practical, and suitable for the IB assessment criteria.

The truth is that a great IA doesn't begin with a complicated experiment, it begins with a well-designed investigation. The strongest Chemistry IAs investigate how changing one independent variable affects a measurable dependent variable while demonstrating thoughtful scientific reasoning, reliable data collection, and meaningful analysis.

This guide is designed to give you inspiration, not topics to copy directly. Before choosing any investigation, always discuss your idea with your Chemistry teacher to ensure it meets your school's safety requirements and the latest IB guidelines.

What Makes an Excellent Chemistry IA?

Students often assume that complex experiments receive higher marks. In reality, examiners reward investigations that demonstrate:

  • A focused and well-defined research question
  • Appropriate control of variables
  • Accurate data collection
  • Good experimental design
  • Strong processing of data
  • Critical evaluation
  • Clear chemical understanding

A simple experiment carried out exceptionally well will almost always outperform a complicated experiment with poor methodology.

How to Generate Your Own IA Topic

A useful starting point is asking yourself:

"What variable can I change, and what measurable chemical property will it affect?"

Common independent variables

  • Temperature
  • Concentration
  • pH
  • Surface area
  • Catalyst concentration
  • Light intensity
  • Pressure
  • Reaction time
  • Ionic strength

Possible dependent variables

  • Reaction rate
  • Gas volume produced
  • Mass change
  • Conductivity
  • pH
  • Enthalpy change
  • Absorbance
  • Voltage
  • Percentage purity

Combining these variables can quickly generate hundreds of potential investigations.

30 IB Chemistry IA Ideas

Reaction Kinetics

  1. How does temperature affect the decomposition rate of hydrogen peroxide?Measure oxygen production over time while keeping catalyst concentration constant.
  2. Investigate how catalyst concentration influences the rate of hydrogen peroxide decomposition.Excellent for discussing collision theory and activation energy.
  3. How does acid concentration affect the reaction rate between magnesium and hydrochloric acid?Measure hydrogen gas production using a gas syringe.
  4. Investigate the effect of particle size on reaction rate.Compare powdered versus granular calcium carbonate reacting with acid.
  5. Determine the activation energy of a chemical reaction using the Arrhenius equation.Collect rate data at different temperatures and construct an Arrhenius plot.

Equilibrium

  1. Investigate how temperature affects the equilibrium position of an iron(III)-thiocyanate system.Analyze color intensity using a colorimeter or spectrophotometer.
  2. How does concentration influence esterification equilibrium?Measure ester yield under varying reactant concentrations.
  3. Study the common ion effect using saturated salt solutions.Relate observations to Le Chatelier's Principle.

Acids and Bases

  1. Compare the buffering capacities of commercial sports drinks.Use acid additions while monitoring pH changes.
  2. Investigate the effectiveness of different antacid tablets.Determine neutralizing capacity through acid-base titration.
  3. Compare the acid content of fruit juices using titration.Explore relationships between acidity and product labeling.
  4. Investigate how storage time affects the acidity of fresh fruit juice.Useful real-world application.

Thermochemistry

  1. Determine the enthalpy of neutralization for different strong and weak acids.Compare experimental values with literature values.
  2. Investigate how carbon chain length affects the energy released during alcohol combustion.Analyze trends in enthalpy of combustion.
  3. Compare the energy content of different snack foods using calorimetry.Relate experimental limitations to heat loss.
  4. Investigate the insulating efficiency of different cup materials during calorimetry.A practical study of experimental error and heat transfer.

Electrochemistry

  1. Investigate how electrolyte concentration affects the voltage of a galvanic cell.Relate observations to electrochemical principles.
  2. Compare corrosion rates of different metals in saltwater.Measure mass loss over time.
  3. Investigate factors affecting the efficiency of copper electroplating.Examine current, concentration, or time as variables.
  4. Study how pH influences corrosion of steel.A highly relevant environmental investigation.

Analytical Chemistry

  1. Determine the vitamin C content of fruit juices before and after storage.Use iodine titration to quantify degradation.
  2. Compare caffeine content in different beverages using UV-Visible spectroscopy.Ideal for students with access to advanced laboratory equipment.
  3. Determine the calcium concentration of different milk brands using EDTA titration.A classic complexometric analysis.
  4. Investigate iron concentration in breakfast cereals.Explore food chemistry using colorimetric analysis.
  5. Compare chloride ion concentrations in bottled mineral waters.Determine chloride content using argentometric titration.

Environmental Chemistry

  1. Investigate dissolved oxygen levels in water collected from different locations.Relate findings to environmental quality.
  2. Compare phosphate concentrations in various fertilizers.Discuss environmental impacts such as eutrophication.
  3. Investigate how activated charcoal removes food dyes from water.Measure absorbance changes using colorimetry.
  4. Compare the effectiveness of natural adsorbents for removing heavy metal ions from water.An excellent environmentally focused investigation.
  5. Investigate how storage conditions affect the degradation of household bleach.Determine sodium hypochlorite concentration over time using titration.

Common IA Mistakes to Avoid

Many students lose marks because they:

  • Choose research questions that are too broad.
  • Select experiments with variables that are difficult to control.
  • Collect insufficient data.
  • Focus on procedure instead of chemical theory.
  • Ignore uncertainties and limitations.
  • Copy experiments directly from the internet without adding originality.

Remember: IB examiners reward scientific thinking, not just successful experiments.

Need Help Choosing the Right IA?

Finding a strong research question is only the first step. Throughout the IA process, students often need guidance with:

  • Refining research questions
  • Experimental design
  • Identifying variables
  • Risk assessments
  • Data processing
  • Graphing and statistical analysis
  • Evaluating uncertainties
  • Improving scientific writing
  • Meeting the IB assessment criteria

With more than 13 years of experience teaching IB Chemistry in international schools and mentoring students across the UK, Australia, the USA, Singapore, Japan, Turkey, Indonesia, and beyond, I've helped students transform good IA ideas into investigations that demonstrate excellent scientific understanding.

Whether you're just starting your IA or looking to improve a draft, personalized guidance can help you work more efficiently, avoid common pitfalls, and maximize your marks while maintaining academic integrity.