Featured in PASCO’s College Chemistry Instructor Guide

College Chemistry Instructor Guide


College Instructor edition with 36 experiments covering introductory and general chemistry topics.

Order of Reaction

Lab Summary

Use a colorimeter to determine the rate constant and the order of reaction.


Students determine the order of reaction by analyzing the reaction rate of crystal violet and NaOH.


Students gain experience conducting the following procedures:

  • Using spectroscopic methods to analyze the reaction rate for a pseudo first-order reaction.
  • Calculating the order of reaction using the initial rate method and a graph of the concentration of crystal violet over time.
  • Determining the equation needed to obtain a straight-line plot.

Sensors / Equipment Used:

PASPORT Colorimeter Sensor


Our PASPORT Colorimeter records all 4 wavelengths simultaneously--no need to guess at wavelength to get a quality measurement.

Materials Used:

Glass cuvette with cap
Beaker, 50-mL - 3
Syringe, 5-mL - 3
Watch glass, 4 in 
0.1 M Sodium hydroxide (NaOH) - 20 mL
1.2 × 10–5 M Crystal violet - 20 mL
Water, distilled - 30 mL
Marking pen 

The Associated Bundle:

Advanced Chemistry Standard Sensor Bundle


Contains the probeware for completing experiments in the College Chemistry lab manual.

Interface Required

This experiment may require software and an interface for data collection.