In: Chemistry
The following data show the rate constant of a reaction measured at several different temperatures. Temperature (K) at 310 has a rate constant (1/s) of 4.65×10^−2 . Temperature (K) at 320 has a rate constant (1/s) of 0.139. Temperature (K) at 330 has a rate constant (1/s) of 0.386. Temperature (K) at 340 has a rate constant (1/s) of 1.01. Temperature (K) at 350 has a rate constant (1/s) of 2.52. Part A) Use an Arrhenius plot to determine the activation barrier for the reaction. Part B) Use an Arrhenius plot to determine the frequency factor for the reaction.
k1 = 4.65*10-2 sec-1
T1 = 310K
K2 = 0.139sec-1
T2 = 320K
logK2/K1 = Ea/2.303R [1/T1 -1/T2]
log0.139/4.65*10-2 = Ea/2.303*8.314 [1/310 -1/320]
0.4755 = Ea/19.147 (0.00322-0.003125)
0.4755 = Ea *9.5*10-5/19.147
Ea = 0.4755*19.147/9.5*10-5 = 9.58*104 Joules
K =A e-Ea/RT
4.65*10-2 = A e-9.58*104/8.314*310
4.65*10-2 = Ae-95800/2577.3
4.65*10-2 = Ae-37.17
A = 4.65*10-2/7.2*10-17 = 6.45*1014 sec-1