Rate Law Equation: Solving for m & k

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The discussion focuses on solving for the reaction order (m) and the rate constant (k) in the rate law equation r = k[H+]^m using provided concentration and reaction rate data. Participants express uncertainty about how to start the calculations and suggest converting the equation into a linear form for easier analysis. One user attempts to derive values for k and m using logarithmic transformations and line fitting, but questions remain about the accuracy of the data and the interpretation of units. Clarifications are sought regarding the meaning of the rate data and how to manipulate it to fit the rate law. The conversation emphasizes the importance of data integrity and proper plotting to validate results.
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Homework Statement



Concentration of Hydrochloric Acid (mol/L)

3

2

1.5

1

0.5

Reaction Rate (s/M)

1.333

13.30

38.67

73.00

1466

Homework Equations



r=k[H+]m (r is rate in M/s, k is constant, [ ] is concentration, m is order of reaction)

The Attempt at a Solution



I'm not entirely sure how to start off this problem. Using the concentration as the "x" value and the rate of reaction as the "y" value, I need to figure out m, the exponent, and if possible: k, which is the constant. How do I start?
 
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Can you think of a mathematical way of converting the r=k[H+]m equation to the y=mx+a form (where m is the exponent you are looking for, and all other things - x, y, a - are easy to calculate from the given data?
 
Borek said:
Can you think of a mathematical way of converting the r=k[H+]m equation to the y=mx+a form (where m is the exponent you are looking for, and all other things - x, y, a - are easy to calculate from the given data?

I am trying that right now. Here is where I've gotten so far:

*using line of best fit slope of the recordings (0.024s-1/M)
log(1/r)=(0.024s-1/M)[H+]+logk
*using random value in the recordings
log0.065=(0.024s-1/M)log3M+logk
-1.19854=logk
k=0.063

I'm also not sure how to get the units for k.
 
What would you expect to get if you plotted log(r) vs log(H+)?

Chet
 
To stop this being a very scholastic excercise please show the plot of your fit. We have no idea how good it is nor whether there are any systematic trends away from your line.
Also no one would be treating data of a reaction that he didn't know what it was, and what ws in the reaction mixture, so please tell us.
Does s/M mean the numbers in the second table are reciprocals of the reaction rate?
What does Log3M mean?
 
Is there any way you could manipulate the given rate to fit the rate law?
 
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