The rate constant of a particular first order reaction is 5.45 x 10^-2 sec^-1 at 40.0 oC. What is the rate constant of this reaction at 65.0 oC if the energy of activation, Ea for this reaction is 65.5 kJ/mol

Respuesta :

Answer: The rate constant for the reaction at 65°C is [tex]0.350s^{-1}[/tex]

Explanation:

To calculate rate constant at 65°C of the reaction, we use Arrhenius equation, which is:

[tex]\ln(\frac{K_{65^oC}}{K_{40^oC}})=\frac{E_a}{R}[\frac{1}{T_1}-\frac{1}{T_2}][/tex]

where,

[tex]K_{65^oC}[/tex] = equilibrium constant at 65°C = ?

[tex]K_{40^oC}[/tex] = equilibrium constant at 40°C = [tex]5.45\times 10^{-2}s^{-1}[/tex]

[tex]E_a[/tex] = Activation energy of the reaction = 65.5 kJ/mol = 65500 J/mol    (Conversion factor:  1 kJ = 1000 J)

R = Gas constant = 8.314 J/mol K

[tex]T_1[/tex] = initial temperature = [tex]40^oC=[40+273]K=313K[/tex]

[tex]T_2[/tex] = final temperature = [tex]65^oC=[65+273]K=338K[/tex]

Putting values in above equation, we get:

[tex]\ln(\frac{K_{65^oC}}{5.45\times 10^{-2}})=\frac{65500J/mol}{8.314J/mol.K}[\frac{1}{313}-\frac{1}{338}]\\\\K_{65^oC}=0.350s^{-1}[/tex]

Hence, the rate constant for the reaction at 65°C is [tex]0.350s^{-1}[/tex]