Question

The temperature dependence of the acid-catalysed hydrolysis of penicillin is investigated. This is a first order reaction that only depends on the concentration of the penicillin. The dependence of the rate constant, k, as a function of temperature is given in the following table: Data Temperature Irek (51) - (K) 285 1.42e – 4 316 0.00138 Determine the activation energy of this reaction. Express your answer in kJ mol-' to the first decimal place (XX.X). 55.0 Your last answer was interpreted as follows: 55.0 Determine the Arrhenius pre-factor, A for this reaction. Express your answer in s-7 to three significant figures (X.XXEX).

Answer 1

Initi al temperature, 7; = 285 K Rate constant of the reaction at 7, k = 0.000142 s-1 Final temperature, 73 = 316 K Rate constant of the reaction at Tz, ks = 0.00138 s-1 Gas constant, R = 8.314 JK-mol-1 According to Athenius theory, Info ( ) (0.00138 M-5- In _ E l 1 1 0.000142 M's" 8.314 JK-'mol- 1285K 316K 2.27 = 8.314 JK-mo1-11 4-1 (0.000344 K-) 3 J 1kJ Activation energy, E = 54.9x10 -7X mol 103 T = 54.9 kJ/mol - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Temperature, T = 285 K Rate constant, k = 0.000142 5-1 Gas constant, R = 8.314x10 kJK-'m01-1 Activatation of the reaction, E = 54.9 kJ/mol Rate constant, k = Aer Arrhenius factor, A = = kete 549 WJbol = (0.000142 3++)e1831-20-w*501"}25 E) = (0.000142 5+)2337 = 0.000142 5-1)(1.16x1050) = 1.64x10s-