Topic T.1 · HL only
Experimental techniques: notes and practice questions
Summary
- This topic focuses on the application of experimental techniques to a greater depth and breadth, often in conjunction with higher level conceptual content.
- It involves a more rigorous approach to data collection and processing, including the propagation of uncertainties involving exponential functions.
- Students are expected to apply standard experimental techniques to investigate more complex chemical systems and phenomena.
- The increased practical work hours at HL reflect the expectation of more sophisticated experimental design and analysis.
How it is examined
Paper 1B, heavily. May 2025 HL Paper 1B TZ1 opened with a standard-solution question: calculate the mass of Na2S2O3 needed, then describe how to prepare the solution, worth 3 marks with named marking points for dissolving in distilled or deionized water, filling to the mark and inverting the flask. The same paper asked for a safety hazard of a product plus a matching precaution, 2 marks, marked as a paired Safety/Precaution alternative. Command terms here are `Describe`, `Outline`, `State` and `Suggest`. Tariffs are 1 to 4 marks.
Key ideas
- Recognize and address relevant safety, ethical or environmental issues in an investigation.
- Measure, to an appropriate level of precision: mass, volume, time, temperature, length, pH of a solution, electric current, electric potential difference.
- Show awareness of the purpose and practice of: preparing a standard solution, carrying out dilutions, drying to constant mass, distillation and reflux, paper or thin layer chromatography, separation of mixtures, calorimetry, acid-base and redox titration, electrochemical cells, colorimetry or spectrophotometry, physical and digital molecular modelling, recrystallization, melting point determination.
Guiding questions
- The guide gives no guiding question for the tools. They are framed as skills, not as a content subtopic.
Linking questions
- Structure 1.1 What factors are considered in choosing a method to separate the components of a mixture? How can the products of a reaction be purified?
- Structure 1.4 What are the considerations in the choice of glassware used in preparing a standard solution and a serial dilution?
- Reactivity 1.1 How can the enthalpy change for combustion reactions, such as for alcohols or food, be investigated experimentally? Why do calorimetry experiments typically measure a smaller change in temperature than is expected from theoretical values?
- Reactivity 3.1 How can titration be used to calculate the concentration of an acid or base in solution?
Practice questions
0 questionsNo question on this page matches those filters. Try another difficulty or paper.
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Where marks are lost
- Reaching for "human error" or "only one trial." A source of error has to be a specific step in the method, not a general apology for the result.
- Joining the dots instead of drawing a curve.
- Naming a chemical instead of the property that distinguishes it, or vice versa. Answering with the nearest fact that comes to mind rather than the fact the command term and stem jointly ask for is a recurring way to answer a question that was not, quite, the one asked.
