Arrhenius Equation: Can We Substitute k with 1/t?

In summary, the Arrhenius equation relates the rate constant k to temperature, with the rate constant being directly proportional to 1/t. It is possible to substitute k with 1/t in the equation, but this is only an approximation and may not hold true for all reactions. The rate constant is a function of temperature and may change over time if temperature changes.
  • #1
fhlfw
2
0
I know the Arrhenius equation is k=Ae^-Ea/RT
The rate constant k is directly proportional to 1/t
(t stands for the time for the reaction to reach a point)

So I wonder if we can substitute k by 1/t in the Arrhenius equation to become 1/t=Ae^-Ea/RT ?

Thanks a lot
 
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  • #2
fhlfw said:
The rate constant k is directly proportional to 1/t
The rate constant is a constant, it doesn't vary with time.
 
  • #3
My bad, I have made a mistake. It should be:

The rate of reaction is directly proportional to both rate constant k and 1/t
So are k and 1/t interchangeable in the Arrhenius equation?
 
  • #4
fhlfw said:
The rate constant k is directly proportional to 1/t
(t stands for the time for the reaction to reach a point)

For the case that you mean something like this:

[itex]\dot \xi = \frac{{\Delta \xi }}{{\Delta t}}[/itex]

That is just an approximation (except for zero-order reactions).

DrClaude said:
The rate constant is a constant, it doesn't vary with time.

Accorting to the Arrhenius equation the rate constant is a function of temperature. If temperature changes over time than the rate constant changes over time too.
 

What is the Arrhenius equation?

The Arrhenius equation is a mathematical formula that describes the relationship between the rate of a chemical reaction and the temperature at which it occurs. The equation is k = A * e^(-Ea/RT), where k is the rate constant, A is the pre-exponential factor, Ea is the activation energy, R is the gas constant, and T is the temperature in Kelvin.

Why is the Arrhenius equation important?

The Arrhenius equation is important because it helps scientists understand the effect of temperature on the rate of a chemical reaction. It also allows for the prediction of reaction rates at different temperatures, which is useful in many fields such as chemistry, biology, and engineering.

What is the relationship between k and temperature in the Arrhenius equation?

In the Arrhenius equation, k is directly proportional to temperature. This means that as temperature increases, the rate constant k also increases. This relationship is described by the exponential term e^(-Ea/RT), where Ea is the activation energy and R is the gas constant.

Can we substitute k with 1/t in the Arrhenius equation?

Yes, we can substitute k with 1/t in the Arrhenius equation. This substitution is known as the Eyring equation and is commonly used to describe the relationship between the rate of a reaction and temperature. The Eyring equation is ln(k/T) = -Ea/RT + ln(A), where k is the rate constant, T is the temperature in Kelvin, Ea is the activation energy, and A is the pre-exponential factor.

Are there any limitations to substituting k with 1/t in the Arrhenius equation?

Yes, there are limitations to substituting k with 1/t in the Arrhenius equation. This substitution assumes that the reaction is a first-order reaction and that the activation energy is independent of temperature. Additionally, the Eyring equation is only applicable for reactions that follow the Arrhenius equation, which may not be true for all reactions.

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