Attention: Safety Recall of Vernier Go Direct Charge Station. Click to learn more.


Reactivity 2.2.11—The rate constant, k, is temperature dependent and its units are determined from the overall order of the reaction.


Here are experiments our science specialists have selected to support this IB* topic.

Rate Law Determination of the Crystal Violet Reaction

Experiment #30 from Chemistry with Vernier

In this experiment, you will

  • Observe the reaction between crystal violet and sodium hydroxide.
  • Monitor the absorbance of the crystal violet solution with time.
  • Graph Absorbance vs. time, ln Absorbance vs. time, and 1/Absorbance vs. time.
  • Determine the order of the reaction.
  • Determine the rate constant, k, and the half-life for this reaction.

Educational Standard
International Baccalaureate (IB) 2025
Organizing concepts
Reactivity 2. How much, how fast and how far?
Reactivity 2.2—How fast? The rate of chemical change
Additional higher level

* The IB Diploma Program is an official program of the International Baccalaureate Organization (IBO) which authorizes schools to offer it. The material available here has been developed independently of the IBO and is not endorsed by it.