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IB Chemistry IA idea · Food and kitchen chemistry

IB Chemistry IA idea: does storage temperature destroy vitamin C in juice?

Every carton says refrigerate after opening; put a number on what warmth actually costs.

  • Food and kitchen chemistry
  • SL good
  • HL ideal
  • Lab Extended Essay potential
  • Syllabus: R2.2.3, R2.2.4, R2.2.12, R2.1.2, S1.4.5, R3.2.1

By Photon Academy · Updated 13 November 2026

These ideas are starting points, not an IA to copy. Never copy an idea blindly: make the question, method and analysis your own, and check your plan with your teacher.

Example research question

To adapt, never to copy

How does storage temperature (5, 25, 45, 65 and 90 °C, for a fixed time) affect the percentage of ascorbic acid remaining in a clear fortified juice, measured by titration with potassium iodate(V) in acid, iodide and starch?

Change the system, the range or the method so the question is yours. Check it against the research question checklist in our Chemistry IA guide.

Variables

You change
Storage temperature of the juice, 5 to 90 degrees C (5 or more values, with a fixed storage time)
You measure
Percentage of ascorbic acid remaining, from iodometric titration with potassium iodate(V) (mg per 100 cm3)
You keep the same
  • Storage time and brand/batch of juice
  • Volume of sample titrated
  • Starch amount and end-point judging
  • Light and headspace of the container

Method

Store equal portions of a clear fortified juice at each temperature for the same time, cool them, then titrate each with standard potassium iodate in the presence of acid, iodide and starch. Titrate an untreated sample as the reference for 100 percent.

Data analysis

Convert titres to mass of ascorbic acid using the iodate/iodine/ascorbic acid mole ratios; plot percentage remaining against temperature; fit a first-order model; propagate burette and pipette uncertainty; compare the label value.

How it works

You change Storage temperature (°C) and measure Vitamin C left (% of original) in Fortified clear juice, keeping Juice brand and batch, Storage time, Titration method the same. Expect a graph of Ascorbic acid remaining / % against Storage temperature / °C: Warmer storage should leave less vitamin C.

Make it yours

Add time as a second variable to obtain rate constants, then an Arrhenius plot; or compare juice packaging and light exposure.

Extended Essay angle

Build a kinetic model of ascorbic acid loss with order, activation energy and the role of oxygen and pH.

Safety

Take care with: hazardous chemicals, heat and hot liquids.

Iodate solutions and dilute acid are irritants; hot water baths up to 90 degrees C scald, so use tongs. Never taste lab juice.

Overused classic: the twist has to carry it.

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