Determination of a Rate Law Lab Report
Determination of a Rate Law
Megan Gilleland
10.11.2012
Dr. Charles J. Horn
Abstract: This two part experiment is designed to determine the rate law of the following reaction, 2I-(aq) + H2O2(aq) + 2H+I2(aq) + 2H2O(L), and to then determine if a change in temperature has an effect on that rate of this reaction. It was found that the reaction rate=k[I-]^1[H2O2+]^1, and the experimental activation energy is 60.62 KJ/mol.
Introduction
The rate of a chemical reaction often depends on reactant concentrations, temperature, and if there’s presence of a catalyst. The rate of reaction for this experiment can be determined by analyzing the amount of iodine (I2) formed. Two chemical reactions are useful to determining the amount of iodine is produced.
1) I2(aq) + 2S2O32-(aq) 2I-(aq)+S4O62-(aq)
2) I2(aq) + starch
Reaction 2 is used only to determine when the production of iodine is occurring by turning a clear colorless solution to a blue color. Without this reaction it would be very difficult to determine how much iodine is being produced, due to how quickly thiosulfate and iodine react. However this reaction does not determine the amount of iodine produced, it only determines when/if iodine is present in solution. Reaction 1 is used to determine how much iodine is produced.
To understand how the rate constant (k) is temperature dependent, another set of data is recorded in week two’s experiment using six trials and three different temperatures(two trials per temperature change). Using the graph of this data we determine the energy required to bend of stretch the reactant molecules to the point where bonds can break or form, and then assemble products (Activation Energy, Ea).
Methods
To perform the experiment for week 1, we first prepare two solutions, A and B, as shown in the data. After preparing the mixtures, we mix them together in a flask and carefully observe the solution, while timing, to see how long it takes for the solution
Megan Gilleland
10.11.2012
Dr. Charles J. Horn
Abstract: This two part experiment is designed to determine the rate law of the following reaction, 2I-(aq) + H2O2(aq) + 2H+I2(aq) + 2H2O(L), and to then determine if a change in temperature has an effect on that rate of this reaction. It was found that the reaction rate=k[I-]^1[H2O2+]^1, and the experimental activation energy is 60.62 KJ/mol.
Introduction
The rate of a chemical reaction often depends on reactant concentrations, temperature, and if there’s presence of a catalyst. The rate of reaction for this experiment can be determined by analyzing the amount of iodine (I2) formed. Two chemical reactions are useful to determining the amount of iodine is produced.
1) I2(aq) + 2S2O32-(aq) 2I-(aq)+S4O62-(aq)
2) I2(aq) + starch
Reaction 2 is used only to determine when the production of iodine is occurring by turning a clear colorless solution to a blue color. Without this reaction it would be very difficult to determine how much iodine is being produced, due to how quickly thiosulfate and iodine react. However this reaction does not determine the amount of iodine produced, it only determines when/if iodine is present in solution. Reaction 1 is used to determine how much iodine is produced.
To understand how the rate constant (k) is temperature dependent, another set of data is recorded in week two’s experiment using six trials and three different temperatures(two trials per temperature change). Using the graph of this data we determine the energy required to bend of stretch the reactant molecules to the point where bonds can break or form, and then assemble products (Activation Energy, Ea).
Methods
To perform the experiment for week 1, we first prepare two solutions, A and B, as shown in the data. After preparing the mixtures, we mix them together in a flask and carefully observe the solution, while timing, to see how long it takes for the solution
References: 1 Determination of a Rate Law lab document, pages 1-6, Mesa Community College CHM152LL website, www.physci.mc.maricopa.edu/Chemistry/CHM152, accessed 10/9/2012. 2 Temperature Dependence of a Rate Constant lab document, pages 1-3, Mesa Community College CHM152LL website, www.physci.mc.maricopa.edu/Chemistry/CHM152, accessed 10/9/2012.