Essay on Determination of the Rate Constant

842 WordsDec 4, 20134 Pages
Determination of the Rate Constant for a Chemical Reaction Department of Chemistry Abstract This experiment was performed to determine the rate constant k, for hydrolysis of tertiary butyl chloride to tertiary butanol. The solvent system for this reaction is 45% isopropyl alcohol and 55% water. The rate of hydrolysis of t-butyl chloride is measured by the decrease in the concentration of this reagent with time. The rate of decomposition of t-butyl chloride must be equal to the rate of formation of hydrochloric acid. The rate of hydrochloric acid formation was measured by titrating the acid produced with a base, NaOH. Introduction The field of chemical kinetics studies the speed of chemical reactions and the reasons that…show more content…
The lab instructor added exactly 1.00 mL of the t-butyl chloride to the flask. The reaction began on this addition and the hydrochloric acid began to produce. This was time “zero” and the stopwatch was started. The contents of the flask were swirled to facilitate the mixing and 2 mL of the 0.25 M sodium hydroxide was added expeditiously. The exact amount of sodium hydroxide solution added to the flask was recorded and the solution turned pink. The pink color produced when sodium hydroxide was added, eventually faded due to the production of hydrochloric acid. The time that had elapsed from the zero time of the t-butyl chloride addition to the color fade was recorded as well as the temperature. 2 mL of sodium hydroxide was added in increments and the times and temperature for the color changes was recorded for approximately 10 additions. At the end of the titrations the contents of the flask were kept and a stopper was placed on the flask and placed in the locker to titrate the excess HCl produced at the next lab. The initial concentration of t-butyl chloride was calculated after the reaction had gone to completion. The number of moles of t-butyl chloride present in the solution before the reaction is the total number of moles of t-butyl chloride added. This quantity is equal to the total moles of HCl produced after the reaction had gone to completion. The total moles of HCl were measured by titrating with sodium hydroxide
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