# Rate constant help for this reaction please

• maistral
In summary, the conversation discusses the process of writing rate constants for a certain reaction. The speaker is unsure of how to correctly write the rate constants for reactions 7 to 12, and is seeking help and clarification. There is also a mention of potential typos and incorrect values in the equations. Despite these challenges, the expert reassures the speaker that they are on the right track.
maistral
TL;DR Summary
Deciphering old journal's rate constant notation.
So I was looking for some rate constants for a certain reaction and I found these:

So I wanted to try them. The problem is, I have no idea how to correctly write the rate constants. Reactions number 1 to 6 is a no-brainer as it's simple Arrhenius. My problem is for rate constants 7 to 12. I am aware of evaluating T at Tr, the problem is I have no idea how to write the entire Arrhenius form and I am somehow unable to wrap my head around it. Can someone give me an idea how? Thanks.

EDIT: I'm guessing, but are these correct? I follow the equation then I compute the preexponential? For rate constant 7, this:

and for rate constant 12, this:

Last edited:
What is the number 1700? Is that ρb? do you know that from somewhere? What else do you know?
Your denominator should have 220.5 in the exponential term, not 158.6. (And that means you should us a value of R in kJ/mol/k.)
Is the activation energy of -30.6 kJ/mol for reaction 6 a typo for 30.6? If not, then it's not "simple Arrhenius"!
With these caveats, I think you are on the right lines.

maistral
Ah, yes. The variable ρb is 1700. And yeah, 158.6 is a typo, and it should be 220.5. Also, for reaction 6 apparently it's really -30.6 as stated by the paper.

Thanks for assuring me that I am somewhat 'okay'. I really appreciate it as I am really confused with this.

## 1. What is a rate constant?

A rate constant is a proportionality constant that relates the rate of a chemical reaction to the concentrations of reactants. It is represented by the symbol k and is specific to a particular reaction at a given temperature.

## 2. How is the rate constant determined?

The rate constant can be determined experimentally by measuring the rate of the reaction at different concentrations of reactants and then using the rate law equation to calculate the value of k. It can also be calculated using theoretical methods, such as transition state theory.

## 3. What factors affect the value of the rate constant?

The value of the rate constant is affected by temperature, the presence of a catalyst, and the nature of the reactants and their concentrations. Generally, an increase in temperature and the use of a catalyst will increase the rate constant, while changes in reactant concentrations can either increase or decrease the value of k.

## 4. How does the rate constant relate to the overall rate of the reaction?

The rate constant is directly proportional to the rate of the reaction. This means that as the rate constant increases, the overall rate of the reaction also increases. However, the rate constant alone does not determine the overall rate of the reaction, as it also depends on the concentrations of reactants and the reaction mechanism.

## 5. Can the rate constant be changed?

The rate constant is specific to a particular reaction at a given temperature and cannot be changed. However, the rate of the reaction can be altered by changing the temperature, using a catalyst, or adjusting the concentrations of reactants. These changes can indirectly affect the value of the rate constant by altering the reaction conditions.

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