IB Chemistry IA Examples to Help You Get Started
What Is the IB Chemistry Internal Assessment?
The IB chemistry Internal Assessment (IA) is a student-designed scientific investigation that forms 20% of your final IB chemistry grade. The task involves choosing your own research question, designing and carrying out your own experiment, collecting and analysing your data, and writing up your findings in a structured report of up to 3,000 words. The chemistry IA is first marked by your teacher before being moderated by an external IB examiner.
Unlike your written examinations, the IA has no set questions and no prescribed experiment. That open-ended structure is what makes it both a valuable opportunity and a common source of stress for students.
The IA is assessed against five criteria:
Personal Engagement evaluates the extent to which you have made the investigation genuinely your own, demonstrating independent thinking, initiative, and a real connection to the topic.
Exploration assesses how well you have identified a focused research question and designed a rigorous, justified methodology to investigate it.
Analysis looks at the quality of your data processing, including correct use of uncertainties, graphical representation, and depth of interpretation.
Evaluation examines your ability to critically reflect on your results, identify meaningful limitations, and propose specific, realistic improvements.
Communication considers the overall clarity, structure, and scientific accuracy of your written report.
Understanding what each criterion demands is essential before studying examples, because a strong IA is not simply one that produces interesting data. A high performing chemistry IA should demonstrate clear scientific thinking at every stage, from the precision of the research question to the honesty of the final evaluation.
One of the most effective ways to develop that understanding is to study examples. What follows is three IB chemistry IA examples covering different topic areas, with detailed commentary on what makes each one work, what strong analysis looks like, and where students most commonly lose marks.
IA Example 1: Kinetics
Kinetics is one of the most popular topic areas for the IB chemistry IA, and for good reason. Reaction rate investigations are experimentally straightforward, connect directly to core syllabus content, and lend themselves naturally to quantitative analysis.
The Research Question
How does the concentration of hydrochloric acid (0.5, 1.0, 1.5, 2.0, and 2.5 mol dm⁻³) affect the rate of reaction with magnesium ribbon, as measured by the volume of hydrogen gas produced in the first 60 seconds at 25°C?
Why This Research Question Works
The most important quality of a strong research question is specificity. Every key decision about the investigation should be visible within the question itself. Notice how this example identifies the independent variable (HCl concentration) with a defined numerical range and unit, names the dependent variable (volume of hydrogen gas produced) with a precise measurement window, and states a controlled variable (temperature) upfront.
Comparing a weak and strong version of the same research question makes this difference concrete:
Weak: How does concentration affect how fast magnesium dissolves in acid?
Strong: How does the concentration of hydrochloric acid (0.5, 1.0, 1.5, 2.0, and 2.5 mol dm⁻³) affect the rate of reaction with magnesium ribbon, as measured by the volume of hydrogen gas produced in the first 60 seconds at 25°C?
The weak version names no units, no range, and no measurement method. It could apply to dozens of different experiments, which signals to the examiner that the student has not yet thought critically about experimental design. The strong version makes every key decision visible, demonstrating the focused thinking that the Exploration criterion rewards.
Experimental Approach
Fixed lengths of magnesium ribbon (2 cm, sanded before each trial to remove the oxide layer and standardise the reactive surface area) are reacted with five concentrations of hydrochloric acid in a conical flask connected to a gas syringe. Each concentration is tested across three repeated trials, and the mean volume of hydrogen gas collected at 60 seconds is recorded. Temperature is maintained at 25°C throughout using a water bath.
One methodological detail worth highlighting is the sanding of the magnesium ribbon. Many students note surface area as a controlled variable, but fail to explain how it was controlled. Simply using the same length of ribbon each time is insufficient because natural variation in ribbon width and the presence of a magnesium oxide layer on the surface can introduce a systematic error across trials. Sanding the ribbon immediately before each trial addresses both issues, and explaining this in the write-up demonstrates the kind of methodological awareness that earns marks in the Exploration criterion.
What Strong Analysis Looks Like
A strong analysis section for this investigation goes well beyond recording gas volumes in a table. It includes the following:
A clearly formatted data table with mean values and propagated uncertainties for each concentration tested
A line graph plotting mean gas volume against HCl concentration, with error bars reflecting the uncertainty in each measurement
A written discussion that connects the observed trend to collision theory, explaining at the molecular level why increasing concentration increases reaction rate by raising the frequency of successful collisions between reacting particles
That third point is where many students lose marks. Describing the trend ‘as concentration increased, the volume of gas produced also increased’ is not the same as explaining it. The Analysis criterion specifically rewards interpretation that draws on chemical theory, not just observation.
Common Mistake Students Make
Students frequently undermine their Evaluation section by attributing variation in results to vague causes. Consider the contrast between these two evaluation statements:
Weak: There may have been some human error when measuring the gas volume, and the magnesium ribbon might not have been the same each time.
Strong: Variation in the surface area of the magnesium ribbon across trials represents a systematic source of uncertainty. Although each piece of ribbon was sanded before use, differences in ribbon width between pieces cut from the same reel mean that the total reactive surface area was not perfectly consistent. Using magnesium powder of a standardised particle size in future trials would eliminate this variable, producing more reproducible results.
The strong version names a specific limitation, explains its chemical significance, and proposes a realistic, concrete improvement. This is precisely the standard the Evaluation criterion demands.
IA Example 2: Acid-Base Chemistry
Acid-base chemistry is one of the most versatile topics for the IB chemistry IA, offering a wide range of experimental techniques that connect directly to real-world contexts. This example demonstrates how a well-chosen comparative structure can elevate an IB chemistry IA beyond a straightforward single-variable experiment, while also making the most of the Personal Engagement criterion.
The Research Question
How does the method of preservation (fresh-squeezed, pasteurised, and UHT-treated) affect the concentration of ascorbic acid in orange juice, as determined by iodometric back titration?
Why This Research Question Works
What distinguishes this research question from a typical acid-base investigation is its comparative structure. Rather than simply varying a continuous variable such as concentration or temperature, the student is comparing three distinct categories of the same product. This design choice has two significant advantages.
The research question is not just identifying a linear trend but interpreting meaningful differences between three groups, each of which has a chemically justifiable reason for producing a different result.
The real-world context makes the Personal Engagement criterion easier to satisfy. A student can connect this investigation to a genuine curiosity about the nutritional value of the juice they consume daily, which reads as far more convincing to an examiner than a forced personal connection to a more abstract topic.
Experimental Approach
A standardised iodine solution is prepared and added in excess to a fixed volume of each juice sample. The ascorbic acid present in the juice reacts with and consumes a portion of the iodine. The excess iodine that remains unreacted is then titrated against a sodium thiosulphate solution, using starch solution as an indicator; the endpoint is identified when the characteristic dark blue-black colour of the starch-iodine complex disappears permanently. The concentration of ascorbic acid in each sample is calculated from the volume of sodium thiosulphate used.
A minimum of five trials per juice type is recommended to produce statistically meaningful data. It is also important to prepare and titrate each sample promptly after opening, for reasons discussed in the common mistakes section below.
What Strong Analysis Looks Like
A common weakness in investigations of this type is that students report their results descriptively without subjecting them to genuine quantitative scrutiny. Strong analysis for this investigation should include the following:
A clearly formatted results table presenting the titre values for each trial, the mean titre, and the calculated ascorbic acid concentration for each juice type, complete with propagated uncertainties expressed to an appropriate number of significant figures
A bar chart comparing the mean ascorbic acid concentration across the three juice types, with error bars representing the uncertainty in each calculated value
A written discussion that interprets the differences between juice types in chemical terms, for instance, explaining that UHT treatment exposes the juice to higher temperatures for longer than pasteurisation, causing greater thermal degradation of ascorbic acid, which is a relatively unstable molecule susceptible to both heat and oxidation
That final point is critical. Noting that UHT-treated juice contains less Vitamin C than fresh juice is an observation. Explaining why, with reference to the chemical properties of ascorbic acid and the conditions involved in each preservation process, is an analysis. The distinction between the two is exactly what separates a mid-range mark from a high one in the Analysis criterion.
Common Mistake Students Make
The error students make in this type of investigation relates to the Evaluation criterion and concerns a limitation that is easy to overlook: the oxidation of ascorbic acid upon exposure to air.
Consider the contrast between these two evaluation statements:
Weak: Some Vitamin C may have been lost during the experiment, which could have affected my results.
Strong: Ascorbic acid is readily oxidised upon exposure to air, meaning that juice samples left open during preparation would yield systematically lower Vitamin C readings than their true concentration. This represents a systematic error that would affect all three juice types but may have introduced variation between trials if sample preparation times were inconsistent. In future investigations, samples could be prepared and titrated immediately after opening, and the procedure conducted in a nitrogen atmosphere to minimise oxidative loss, producing results that more accurately reflect the ascorbic acid concentration of each juice type as preserved.
The weak evaluation identifies that something went wrong but offers no chemical reasoning and no meaningful improvement. The strong evaluation names the specific chemical process responsible for the error, explains how it would affect the data, and proposes a concrete, chemically informed solution.
IA Example 3: Electrochemistry
An electrolysis investigation gives you a specific quantitative prediction to test against your results. That built-in theoretical benchmark is what makes this topic particularly powerful and the feature that most distinguishes a strong electrochemistry IA from a merely competent one.
The Research Question
How does varying the current (0.2, 0.4, 0.6, 0.8, and 1.0 A) affect the mass of copper deposited on a steel cathode during the electrolysis of copper(II) sulphate solution over 10 minutes?
Why This Research Question Works
The strength of this research question lies in the direct connection it establishes between the experimental design and a testable theoretical law. Faraday's first law of electrolysis predicts that the mass of a substance deposited at an electrode is directly proportional to the quantity of electric charge passed through the solution. By varying current across five values whilst holding time constant, the student is able to calculate the total charge passed at each setting and compare the theoretically predicted mass of copper deposited against the experimentally obtained value.
Note also the specificity of the research question itself. The independent variable (current) is stated with a defined numerical range and unit. The dependent variable (mass of copper deposited) is clearly identified. The electrode material, electrolyte, and duration are all specified. Each of these details signals to the examiner that the student has thought carefully about the experimental design before beginning, which is what the Exploration criterion looks for.
Experimental Approach
A simple electrolytic cell is assembled using a copper anode and a pre-cleaned, pre-weighed steel cathode, both submerged in 100 cm³ of 0.5 mol dm⁻³ copper(II) sulphate solution. A variable resistor and ammeter are used to set and monitor the target current throughout each trial. Each trial runs for exactly 10 minutes, after which the cathode is removed, rinsed carefully with distilled water, dried, and reweighed on an analytical balance. Three trials are conducted at each current value to allow for meaningful uncertainty analysis.
One methodological detail that students frequently overlook is the cleaning of the cathode between trials. Any residual copper from a previous trial will affect the surface conditions of the electrode and introduce inconsistency across the data set. Cleaning the cathode with fine sandpaper and rinsing with distilled water before each trial standardises the surface conditions, reducing a potential source of systematic error. Explaining this decision in the write-up demonstrates the methodological awareness that earns marks in the Exploration criterion.
What Strong Analysis Looks Like
The most analytically rewarding step in this investigation is the comparison between experimental and theoretical results. Using Faraday's first law, the theoretical mass of copper deposited at each current can be calculated using the following relationship:
m = (I x t x M) / (n x F)
Where m is the mass deposited in grams, I is the current in amperes, t is the time in seconds, M is the molar mass of copper (63.55 g mol⁻¹), n is the number of electrons transferred per ion (2 for Cu²⁺), and F is Faraday's constant (96,485 C mol⁻¹).
Strong analysis for this investigation should include the following:
A results table presenting the experimental mass deposited at each current alongside the theoretically calculated value, with propagated uncertainties expressed to an appropriate number of significant figures
A line graph plotting both the experimental and theoretical mass values against current on the same axes, allowing for a direct visual comparison
A written discussion calculating the percentage difference between experimental and theoretical values at each current setting, and offering a chemically reasoned explanation for why the two diverge, particularly at higher currents where competing electrode reactions and increased solution resistance are likely contributors
Common Mistake Students Make
The Evaluation section is where students most commonly underperform in this type of investigation. Limitations are named without being explained, and proposed improvements are vague rather than specific. Consider the following contrast:
Weak: The current may not have stayed constant throughout the experiment, and the electrode might not have been completely dry when weighed, which could have caused errors in my results.
Strong: Fluctuations in current during each trial, despite the use of a variable resistor, represent a systematic uncertainty that directly affects the total charge passed and therefore the theoretical mass calculation. A potentiostat, which maintains a precisely constant current regardless of changes in solution resistance, would eliminate this variability. Additionally, inconsistent drying of the cathode prior to weighing introduces a random error in the mass measurements; implementing a standardised drying protocol, such as placing the electrode in a desiccator for a fixed duration of five minutes after rinsing, would reduce this variability and improve the reproducibility of results across trials.
The difference between these two responses is the precision with which those limitations are explained and the specificity of the proposed improvements. The strong version names the exact instrument that would resolve the current fluctuation issue, quantifies the drying duration, and connects each limitation explicitly to its effect on the data. Developing this habit of precise, chemically grounded critical reflection is an effective step students can take to improve their Evaluation score.
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The examples above illustrate what a strong IB Chemistry IA looks like across three key topic areas, but developing one from scratch requires more than a good example to follow. BartyED's expert IB Chemistry tutors work one-to-one with students in-person and online to help them craft a focused research question, build a rigorous methodology, and produce the kind of precise, chemically grounded analysis and evaluation that earns top marks.
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Frequently Asked Questions
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A good IB chemistry IA topic is anything within the field that students generally find interesting. The thing to keep in mind is that the IA is a long term project, so choosing a topic that is engaging will help retain interest throughout the development and drafting processes.
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A good chemistry IA begins with a well thought out research question. Without this as an anchor, even the most talented students will struggle.
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The IB chemistry IA is assessed based on five criteria: personal engagement; exploration; analysis; evaluation; and communication.
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There is no page limit for the chemistry IA. Rather, it should aim to be no more than 3,000 words in length.