AP Chemistry

Kinetics of Crystal Violet Fading Lab Report

Components of the Lab Report: Introductory Activity • Heading • Summary of the Background Information (Flinn Lab) * • Answers to the Prelab Questions (Flinn Lab)* • Purpose* o Objective: ! Write one based on the Guided Inquiry Portion of the Lab o IV and DV • Experimental Design Introductory Activity * o Procedure: ! Summarize the procedure in the Introduction Activity section of the Flinn Lab. o Data Table ! Create one just for this section. • Experimental Design for Guided Inquiry* o Procedure: ! Safety ! Materials ! Step by Step Procedure • Include directions only for Guided Inquiry Part A, we will not be doing B. • Pay attention to the questions within the directions, they will help you write the procedure. o Data Table* ! Remember, we are only doing part A. • Analysis: Graph o Generate a calibration curve for crystal violet (do you remember Beer’s Law?) o Generate the three graphs outlined in Guided Inquiry Step #3 • Analysis: Calculations o Determine the pseudo-rate law for the fading of crystal violet (omit OH-) o Determine the pseudo-rate constant kʹ. o Determine the half-life for the reaction your carried out. • Conclusion o Summary ! What is the rate law for the reaction you carried out? o Purpose Analysis ! Support your answer using your data. ! Address why the [OH-] is not considered in your answer. o Error Analysis ! Explain one factor contributing to the error in your investigation. ! Explain how the error affected results • BE SPECIFIC ! Suggest ways of minimizing the error identified. o Application ! The experiment is repeated, this time using 0.1 M NaOH and 0.2 M NaOH (the amount of NaOH used in each trial is kept the same). The value of the pseudo-rate constant kʹ was measured for the two different concentrations of [OH−]. The value of kʹ was found to be 0.13 at [OH−] = 0.2 M, and 0.061 when [OH−] = 0.1 M. Show how you can rearrange and combine the following two equations (see Equation 4) to solve for rate order with respect to [OH-]. • 0.13 = kʹ = k[0.2]m and 0.061 = kʹ = k[0.1]m ! Based on your answer to the above question and your data from the lab, write the complete rate law for the decomposition of crystal violet in the presence of hydroxide. • AP Chemistry Review Questions o Do them. o Show your work.