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The Chemical Educator

ISSN: 1430-4171 (electronic version)

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Abstract Volume 18 (2013) pp 126-130
DOI 10.1007/s00897132481

Guided Inquiry: The Determination of the Reaction Rates of Potassium Iodate and Sodium Sulfite

Joseph K. Rugutt*, Michelle K. Johnson, Jennifer L. Langston, Coy R. Guffey, Alexandria L. Cook, and Lindsey R. Ewen

Department of Chemistry, Missouri State University-West Plains, 128 Garfield, West Plains, MO 65775,
Received April 27, 2012. Accepted February 23, 2013.

Published: 24 May 2013

Abstract. The rate of a reaction is vital to any chemical system. The rate of a chemical reaction can be influenced markedly by changes in concentration of reactants, temperature, surface area, action of catalysts, and the nature of the reactant. The effect of concentrations on the rate of reaction between potassium iodate (KIO3) and sodium sulfite (Na2SO3) solutions was investigated using starch as an indicator. Using the slopes of average tangent lines, the overall rates of the reactions were determined to be 2×10–4 and 2×10–5 mol/(L×s) for KIO3 and Na2SO3, respectively. In order to gain a better understanding of rates of reaction, the principles of activation energy, catalysts, and collision theory were used to rationalize the data.

Key Words: Laboratories and Demonstrations; general chemistry; guided inquiry; reaction rate; activation energy; collision theory; chemical kinetics 

(*) Corresponding author. (E-mail:

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