The rate constant for a certain chemical reaction is 77.0 s-1 at a temperature of 20.0°C. If the activation energy for this reaction is 52. kJ/mole, what is the rate constant at a temperature of 30.0°C?

Respuesta :

Answer:

[tex]155.65\ s^{-1}[/tex]  is the rate constant at a temperature of 30.0 °C.

Explanation:

Using the expression,

[tex]\ln \dfrac{k_{1}}{k_{2}} =-\dfrac{E_{a}}{R} \left (\dfrac{1}{T_1}-\dfrac{1}{T_2} \right )[/tex]

Wherem  

[tex]k_1\ is\ the\ rate\ constant\ at\ T_1[/tex]

[tex]k_2\ is\ the\ rate\ constant\ at\ T_2[/tex]

[tex]E_a[/tex] is the activation energy

R is Gas constant having value = 8.314 J / K mol  

Thus, given that, [tex]E_a[/tex] = 52 kJ/mol = 52000 J/mol (As 1 kJ = 1000 J)

[tex]k_2=?[/tex]

[tex]k_1=77.0s^{-1}[/tex]  

[tex]T_1=20\ ^0C[/tex]  

[tex]T_2=30\ ^0C[/tex]  

The conversion of T( °C) to T(K) is shown below:

T(K) = T( °C) + 273.15  

So,  

T = (20 + 273.15) K = 293.15 K  

T = (30 + 273.15) K = 303.15 K  

[tex]T_2=303.15\ K[/tex]

So,

[tex]\ln \frac{77.0}{k_2}\:=-\frac{52000}{8.314}\times \left(\frac{1}{293.15}-\frac{1}{303.15}\right)[/tex]

[tex]\frac{77}{k_2}=e^{-\frac{52000}{8.314}\left(\frac{1}{293.15}-\frac{1}{303.15}\right)}[/tex]

[tex]k_2=77e^{\frac{520000}{738852.06466}}[/tex]

[tex]k_2=155.65\ s^{-1}[/tex]  

[tex]155.65\ s^{-1}[/tex]  is the rate constant at a temperature of 30.0 °C.