Experimant (7):The effect of temperature on the reaction rate Theory The specific rate constant is related to the temperature by the expression Or in the integrated forms:

Arrhenius Equation

In this experiment the hydrogen ion catalyzed hydrolysis of methyl acetate ester has been selected.

Object: To study the effect of temperature on the rate constant Procedure: 1-Pipet 100 mL of the 1 M HCl into a stoppered flask and place it in the water bath maintained at 25ºC. 2-Place at the same time-the flask of methyl acetate in the water bath. 3-Allow both flasks to come to thermal equilibration, this will take about 15 min. 4-Pipet 5 mL of the ester in a small bottle and directly record its weight, and then pour it to the acid. Record the time of mixing. 5-Remove 5 mL samples of the reaction mixture according to the time schedule given below. Drain them into Erlenmeyer flask containing 75 mL of ice and water. 6-Accomplish the titration of these mixtures against the standard NaOH solution.

Table (1): Table (2): T, C Wt. of 5 mL Ester Moles of ester Time, min   Time, min V NaOH Moles NaOH Moles AA formed Moles NaOH – moles HCl [Ester] M - Ln [Ester]  

Useful data: MW of Methyl acetate = [Ester]final = moles AA (formed) – moles HCl