Finding First Order Rxn Rate Constant

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SUMMARY

The discussion centers on calculating the first-order reaction rate constant for a reaction involving a 1 M H2SO4 solution and a ferrous complex, measured using a spectrophotometer at a wavelength of 510 nm. The slope of the ln O.D. vs. time graph is -0.008, indicating that the rate constant (k) is 0.008 min-1. The participant expresses confusion about determining the concentration of reactant [A] for the rate equation R = k[A], despite correctly identifying k as 0.008 min-1.

PREREQUISITES
  • Understanding of first-order reaction kinetics
  • Familiarity with spectrophotometry and absorbance measurements
  • Knowledge of the Beer-Lambert Law (A = E*l*c)
  • Basic algebra for manipulating rate equations
NEXT STEPS
  • Study the Beer-Lambert Law to understand how to relate absorbance to concentration
  • Learn how to calculate concentration [A] from absorbance measurements
  • Explore the derivation of the first-order rate law and its applications
  • Investigate methods for determining reaction rates using spectrophotometric data
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Chemistry students, laboratory technicians, and researchers involved in reaction kinetics and spectrophotometric analysis.

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Homework Statement



I have a first order reaction where I need to find the rate constant. I have the following data:
T = 30'C
the slope of a graph with ln O.D vs T (minutes) is -0.008 so k is 0.008.

The Attempt at a Solution



I'm unsure about what reaction I would need here. This is for an acid sol'n (1 M H2SO4) mixed with a ferrous complex in a spectrophotometer with a 510 nm wavelength. I know there's the formula A = E*l*c where E is epsilon but I don't know how to determine the first order rate constant from this. For first order rate reactions: R = k[A] I know that k is 0.008 but I don't know how to get [A]
 
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Isn't the rate constant simply k=0.008/min?
 

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