Gas Pressure Sensor Monitored Iodide-Catalyzed Decomposition Kinetics of Hydrogen Peroxide: An Initial Rate Approach

TCE

The Chemical Educator

ISSN: 1430-4171 (electronic version)

Table of Contents

Abstract Volume 13 Issue 4 (2008) pp 227-230

Gas Pressure Sensor Monitored Iodide-Catalyzed Decomposition Kinetics of Hydrogen Peroxide: An Initial Rate Approach

Frazier W. Nyasulu* and Rebecca Barlag

Department of Chemistry and Biochemistry, Ohio University, Athens, OH 45701, nyasulu@ohio.edu
Received March 31, 2006. Accepted May 11, 2007.

Published online: 27 July 2008

Abstract. In this general chemistry laboratory experiment, the iodide-catalyzed decomposition kinetics of H₂O₂(aq) to H₂O(l) and O₂(g) is determined using the method of initial rates. The reagents (total volume 5 mL) are added to an open 25-mL test tube, and after capping the test tube, the gas pressure versus time data is collected using a datalogger and a pressure sensor. The plots, which are viewed on the datalogger in real time, are extraordinarily linear allowing for a straight-forward determination of the initial rate of reaction (slope) in 20 to 25 seconds of data collection. The reaction is first order with respect to iodide and first order with respect to hydrogen peroxide and the rate constant is 0.011040 ± 0.000013 M^–1s^–1(N = 22).

Key Words: Laboratories and Demonstrations; general chemistry; kinetics

(*) Corresponding author. (E-mail: nyasulu@ohio.edu)

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Supporting Materials:

Instructor notes, the laboratory handout, and the excel spreadsheet as available as supporting materials (1.56 MB)