Reaction Kinetics

Reaction Kinetics: Rate of Reaction

Of Tertiary-Butyl Bromide

Purpose: The purpose of this experiment is to find the order of t-BB graphically, to find the k (rate constant) at 0˚ C and at room temperature, also to find the Ea (activation energy).

Principles: Several different chemical kinetic principles were used in this experiment. The reaction rates of this chemical equation were determined experimentally. This then allowed the reaction mechanisms (i.e. orders of each component, rate constant, etc.). These mechanisms were ultimately determined to be compiled to form a rate law.

Rate = k[A]m[B]n

Integrated rate laws are used to determine concentrations of reactants at certain times. However, these integrated equations can only be used after the experimental data is collected. Temperature has an effect on the rates of reactions. Swedish chemist, Svante Arrhenius, discovered that the rate constant of a reaction increased logarithmically in proportion to the reciprocal of the absolute temperature. This is expressed mathematically as:

k = Ae-ΔE/RT

Method: 100 mL of water/ Isopropyl Alcohol were added to a 250 mL Earlenmeyer flask along with 15 drops of phenolphthalein. A buret was washed with soapy water and rinsed with 0.2 M NaOH. The buret was then filled to 0.00 mL. 2.00 mL of NaOH were added to the flask and it was placed into an ice-water bath.

t-BB was injected into the flask by the lab assistant with this exact time being noted. The exact time was recorded once again when the solution became colorless.

About two mL of NaOH were added to the solution and the time recorded when this became colorless. This was done until seven time readings