Solved: Rate Laws (Section)Consider the reaction of

Chapter , Problem 38E

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4.38] Consider the reaction of peroxydisulfate ion \(\left(S_{2} O_{8}^{2-}\right)\) with iodide ion \(\left(I^{-}\right)\)  in aqueous solution:

\(S_{2} O_{8}^{2-}(a q)+3 I^{-}(a q) \rightarrow 2 S O_{4}^{2-}(a q)+I_{3}(a q)\)

At a particular temperature the initial rate of disappearance of \(S_{2} O_{8}^{2-}\) varies with reactant concentrations in the following manner:

Experiment	\({\left[S_{2} O_{8}^{2-}\right](M)}\)	\({\left[I^{-}\right](M)}\)	Initial Rate \((M / s)\)
1	0.018		\(2.6 \times 10^{-6}\)
2	0.027		\(3.9 \times 10^{-6}\)
3	0.036		\(7.8 \times 10^{-6}\)
4	0.050		\(1.4 \times 10^{-5}\)

(a) Determine the rate law for the reaction and state the units of the rate constant.

(b) What is the average value of the rate constant for the disappearance of \(S_{2} O_{8}^{2-}\) based on the four sets of data?

(c) How is the rate of disappearance of  \(S_{2} O_{8}^{2-}\)  related to the rate of disappearance of \(I^{-}\) ?

(d) What is the rate of disappearance of \(I^{-}\)  when \({\left[S_{2} O_{8}^{2-}\right]=0.025 M \text { and }\left[I^{-}\right]=0.050 M}\)?

Equation Transcription:

   

   

     

 

   

   

   

   

   

 

 

 

Text Transcription:

(S2O82-)  

(I-)    

S2O82-(aq)+3I-(aq) \rightarrow 2SO42-(aq)+I3-(aq)    

S2O82-

[S2O82-](M)    

[I-](M)    

(M/s)

2.6 x 10-6  

3.9 x 10-6  

7.8 x 10-6    

1.4 x 10-5

S2O82-

S2O82-

I-

I-

[S2O82-]=0.025M  and  [I-]=0.050M