Chemistry Homework: Second Order Rate Equation and Calculating Rate Constant

Click For Summary
SUMMARY

The discussion centers on determining the order of a chemical reaction and calculating the rate constant for a reaction represented as A → products. The provided concentration-time data suggests that the reaction does not conform to simple first or second order kinetics, as the concentration decreases by half at irregular time intervals. The user concludes that traditional methods for calculating the rate constant yield inconsistent results, indicating a more complex reaction mechanism may be at play.

PREREQUISITES
  • Understanding of first and second order reaction kinetics
  • Familiarity with rate equations and their integrated forms
  • Knowledge of half-life calculations in chemical reactions
  • Ability to analyze concentration-time data
NEXT STEPS
  • Research the method of half-life reactions to determine reaction order
  • Explore complex reaction mechanisms beyond first and second order
  • Learn about the Arrhenius equation for temperature dependence of rate constants
  • Investigate the use of graphical methods for analyzing reaction kinetics
USEFUL FOR

Chemistry students, educators, and researchers involved in kinetic studies and reaction mechanism analysis will benefit from this discussion.

jim Wang
Messages
1
Reaction score
0

Homework Statement


Is this first or second order rate? Calculate the rate constant and be certain to give its units.
A-->products
Chart
A (mM) / Time
1 / 0
.5 / 11
.25 / 20
.1 / 48
.05 / 105


Homework Equations


Well wikipedia has both the first and second order integrated reactions there http://en.wikipedia.org/wiki/Rate_equation

but I have a feeling that this is some sort of weird rate reaction.


The Attempt at a Solution



At first glance it looks like a second order rate but If I plug in in an attempt to find k none of the K values match. I also tried a first order reaction and that didn't work as well. Also due to the fact that the first three concentrations go down by half and the time is not consistent it is most likely not a simple first order exponential decay. You just need to trust me that plugging the times into the regular second order rate equation does not come out with a homogeneous rate constant.


Well thanks guys in advanced I'm stumped.
 
Last edited:
Physics news on Phys.org
You can try the method of "half life reaction" it will give a n order (numeric)
 

Similar threads

Chemistry Why is My Second-Order Reaction Rate Calculation Incorrect?
  • · Replies 6 ·
Replies
6
Views
3K
Chemistry Decomposition of Sucrose: Understanding the Rate and Order of Reaction
  • · Replies 3 ·
Replies
3
Views
3K
Reaction rate, rate equation and half life
  • · Replies 4 ·
Replies
4
Views
4K
Biology How Do Stoichiometric Coefficients Affect Reaction Rates?
  • · Replies 3 ·
Replies
3
Views
3K
Question regarding the rate law of a reaction
  • · Replies 2 ·
Replies
2
Views
2K
Rate Constant Determination - Isolation Method Homework Help Needed
  • · Replies 5 ·
Replies
5
Views
4K
Rate constant calculation Using the Arrhenius equation
  • · Replies 1 ·
Replies
1
Views
3K
Finding order of reaction & rate constant
  • · Replies 3 ·
Replies
3
Views
5K
How Do You Propose a Reaction Mechanism for a Multi-Step Reaction?
  • · Replies 10 ·
Replies
10
Views
5K
Rate of Reaction: Solving to Find Time for [A] to Reach X Conc.
  • · Replies 17 ·
Replies
17
Views
3K