What is the impact of temperature on the rate of the reaction at 45C?

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Discussion Overview

The discussion centers on the impact of temperature on the rate of a chemical reaction, specifically examining the rate constant at 45°C based on given data at 35°C. Participants explore the application of the Arrhenius equation and the implications of temperature changes on reaction rates.

Discussion Character

  • Homework-related
  • Mathematical reasoning
  • Technical explanation

Main Points Raised

  • One participant attempts to use the Arrhenius equation to calculate the rate constant at 45°C, expressing uncertainty about the correctness of their approach.
  • Another participant points out that the calculation performed yields a ratio of rates rather than the rate itself, suggesting a need to find the pre-exponential factor (A) first.
  • A different participant notes that the activation energy constant is given in J/mol K, implying that temperatures should be converted to Kelvin for accurate calculations.
  • Some participants discuss the relevance of the temperature change (delta T) in the context of the calculations, indicating that the method of deriving the expression may vary.

Areas of Agreement / Disagreement

Participants express differing views on the correct approach to calculating the rate constant and the significance of temperature in the calculations. There is no consensus on the method to be used or the interpretation of the results.

Contextual Notes

Participants highlight potential limitations in the calculations, such as the need for temperature conversion and the method of deriving the rate expression. There are unresolved aspects regarding the assumptions made in the calculations.

Who May Find This Useful

Students studying chemical kinetics, particularly those interested in the effects of temperature on reaction rates and the application of the Arrhenius equation.

Saterial
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Homework Statement


At 35C, the rate constant for the reaction: C12H22O11 + H20 --> C6H12O6 + C6H12O6 is k=6.2 x 10^-5 s-1. The activation energy for the reaction is 108 kJ/mol. What is the rate constant for the reaction at 45C? Determine the impact on the rate.


Homework Equations


r=Ae^-Ae/RT
r=k[C12H22O11][H2O]

The Attempt at a Solution



I don't know if I am even using the right equation, (Arrhenius equation) however I tried seperating the reaction into 35C and 45C stages and analyzed from there. At 35C, Ae is given so I plugged the Ae into the Arrhenius eq at 45C and cancel out the A base as it is the same at both 35C and 45C.

Ended up with :
r=e^(-108000/8.314*10). (change in temp of 10C)

Does this make any sense or even work? If so, what does the second part of impact on the rate mean?

Thanks a bunch.
 
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What you found is ratio of rates, not rate. Use data for 35 deg C to find A, then just plug and chug for 45 deg C.
 
Also, given that the constant is given by J/Mol K, I would have thought you were supposed to use Kelvins instead of degrees Celsius.
 
When it comes to delta T it doesn't matter. A lot depends on how Saterial got to the expression shown.
 
Borek said:
When it comes to delta T it doesn't matter. A lot depends on how Saterial got to the expression shown.

Ah. Missed we were using delta.
 

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