What is the value of the rate constant at 17 degrees celsius?
The Ea = 122 kJ/mol
I know I have to use ln k = ln A - Ea/RT.. but I don't know how to calculate it without known ln A and how do you find ln A
Thank you for your help!
ln(k2/k1) = (Ea/R)(1/T1 -1/T2)
i have no idea how to apply this formula as we can only use one temperature and this requires the use of two.
Sorry. I have you confused with Gary who posted a similar question.
Is this problem posted exactly as it appears in your homework?
Well, they also gave this information: A reaction has a rate constant of 1.24×10−4 at 25 C and 0.228 at 79 C.
Am I missing something? You have two k values (use one of them) and two T values (use one of them that goes with the k you decided to use) and you have the Ea. So you want k at 17. What's the problem? Plug those values into the equation I wrote and solve for the new k at 17 C.
Im not getting the right value.I get 1.24*10^-4 and that's not correct.
I set this up.
ln(k2/1.24E-4) = (122,000/8.314)(1/298 - 1/290) and solved for k2. I obtained 3.19E-5.
Then just for the fun of it I set this up.
ln(k2/0.228) = (122,000/8.314)(1/352 - 1/290) and solve for k2. I obtained 3.07E-5. Pretty close for such a wide difference in k. The 3.19E-5 should be more accurate (comparing k at 25 with k at 17) instead of comparing k at 79 with k at 17.
To calculate the value of the rate constant (k) at 17 degrees Celsius using the Arrhenius equation (ln k = ln A - Ea/RT), you would need the value of the pre-exponential factor (A) or the natural logarithm of A (ln A).
However, if you do not have the value of ln A, you won't be able to directly calculate the rate constant. In this case, you would need additional information or assumptions to proceed.
One option is if you have experimental data for the rate constant, k, at different temperatures. By measuring the rate at different temperatures, you can plot ln k against the inverse of temperature (1/T) and determine the slope of the line, which corresponds to -Ea/R.
From -Ea/R, you can then substitute the given value of Ea and the universal gas constant (R = 8.314 J/(mol K)) to solve for ln A.
Another option is if you have additional information about the reaction or system. If you know the reaction order, for example, you can make use of the rate equation to find the value of ln A. The rate equation may contain additional parameters or constants that allow you to solve for ln A.
In summary, to calculate the value of the rate constant at 17 degrees Celsius using the Arrhenius equation, you need additional information such as experimental data, reaction order, or other parameters to determine the value of ln A.