the following reaction has an activation energy of 262 kJ/mol. C4H8(g)->2C2H4(g). At 600 K the rate constant is 6.1*10^-8s^-1. What is the value of the rate constant at 765.0 K?
Step 1: According to Arrhenius Equation, We can relate rate constants with activation energy
log(k2/k1) = (Ea / 2.303 R) x
(T2 - T1 / T1 xT2)
------------------- (1)
Step 2: Given Datas
T1 = 600 K K1 = 6.1 x 10-8
T2 = 765 K K2 = ??
R = 8.314 Jmol-1 K-I
Ea = 262 kJ/mol which will be convert to J/mol because R is in
J/mol K-1 so...
Ea = 262000 J mol-I K-I
Step 3: Substituting the values in Eq(1)
log(k2/ 6.1 x 10-8 s-1) = (262000 J mol-I K-I / 2.303 x8.314 J mol-I K-I) x (765K - 600 K / 600K x 765K)
log(k2) - log(6.1 x 10-8 s-1) = (13683.5) x (0.0003594)
log(k2) - log(6.1 x 10-8 s-1) = (13683.5) x (3.594 x 10-4)
log(k2) = log(6.1 x 10-8 s-1) + (13683.5) x (3.594 x 10-4)
log(k2) = log(6.1 x 10-8 s-1) + (49178.5x 10-4)
log(k2) = -7.2147 +4.9179
log(k2)= -2.2977
k2 = 0.005038 s-1
k2 = 5.038 x 10-3 s-1
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