In: Chemistry
Determine the activation energy (kJ) from the following table.
Temperature (K) 427 417 409 407 399
k (s-1) 0.00108 0.000410 0.000208 0.00016 0.0000763
A.25 | |
B.77 | |
C.89 | |
D.134 |
You have discovered a new enzyme and want to characterize its function. The reaction catalyzed is 20 times more rapid at 25° C than at 4° C. Calculate the activation energy (kJ) for the reaction.
A.24 | |
B.41 | |
C.83 | |
D.100 |
logK2/K1 = Ea/2.303R[1/T1 -1/T2]
log0.00108/0.0000763 = Ea/2.303*8.314 [1/399 -1/427]
1.1508 = Ea/19.147 (0.0025-0.00234)
Ea = 1.1508*19.147/(0.0025-0.00234)
= 1.1508*19.147/0.00016
= 137714 J = 137.714KJ
logK2/K1 = Ea/2.303R[1/T1 -1/T2]
T2 = 25C = 25+273 = 298K
T1 = 4C = 4+273 = 277K
log20 = Ea/2.303*8.314 [1/277-1/298]
1.3010 = Ea/19.147 (0.0036-0.00335)
Ea = 1.3010*19.147/(0.0036-0.00335)
= 24.91/0.00025 = 99640J = 99.640KJ = 100KJ