Solving the Order of Reactants: BrO3-, I-, H+

[disneychannel]

Homework Statement

Calculate Order of Each Reactants
I am doing a lab on the reaction rates for k[BrO₃^-]^y[I^-]^x[H⁺]^z However when I do my calculations based on my data, i get different orders! The teacher said that will happen but how am I supposed to know which is the right one?

The Attempt at a Solution

log(5.3E-7/7.6E-7)/log(0.0017/0.0033)=0.5-I
log(5.3E-7/1.2E-6)/log(0.0067/0.0133)=1- BrO3-
log(5.3E-7/2.8E-6)/log(0.0067/0.0200)=1.5- BrO3-
log(1.2E-6/2.8E-6)/log(0.0133/0.0200)=2- BrO3-
log(5.3E-7/2.02E-6)/log(0.0167/0.0333)=2- H
log(5.3E-7/3.8E-6)/log(0.0167/0.0500)=2-H
log(2.02E-6/3.4E-6)/log(0.0333/0.0500)= 1 H

 

[PhaseShifter]

I can't tell from your math what your numbers actually mean, since none of them have units or descriptions.

Can you list your data for each set of measurements?

 

[disneychannel]

Exp #---- Time of reaction (s) - -- Reaction rate (M/s)---- Initial Concentrations (M)
Trial 1---Trial 2---Trial 3-- -Average --- [I-] --- [BrO3-] ------[H+]
1- 26.27- -- 27.2 --- 24.5 ---25.99 ---5.3E-7---------0.0017---0.0067 ---0.0167

3 -9.59 --- 7.79 --- 5.68--- 7.69--- 1.8E-6------- 0.0050--- 0.0067--- 0.0167
4- 12.87 --- 11.8--- 10.75--- 11.8---1.2E-6 -------0.0017---0.0133 ---0.0167
5 -4.49---4.40--- 5.90--- 4.90 ---2.8E-6-------- 0.0017--- 0.0200--- 0.0167
6- 6.21---7.56--- 6.72 --- 6.83---2.02E-6---------0.0017---0.0067---0.0333
7- 4.39---4.14 --- 3.74--- 4.09--- 3.4E-6--- ---------0.0017--- 0.0067--- 0.0500for BrO3 i used experiments 1,4,5
for I i used experiment 1 and 3
and for H i used experiments 1,6 , 7

Calculations

log(5.3E-7/7.6E-7)/log(0.0017/0.0033)=1-I
log(5.3E-7/1.2E-6)/log(0.0067/0.0133)=1- BrO3-
log(5.3E-7/2.8E-6)/log(0.0067/0.0200)=1.5- BrO3-
log(1.2E-6/2.8E-6)/log(0.0133/0.0200)=2- BrO3-
log(5.3E-7/2.02E-6)/log(0.0167/0.0333)=2- H
log(5.3E-7/3.8E-6)/log(0.0167/0.0500)=2-H
log(2.02E-6/3.4E-6)/log(0.0333/0.0500)= 1 H

 

[PhaseShifter]

Calculations

log(5.3E-7/7.6E-7)/log(0.0017/0.0033)=1-I

Where does the 7.6e-7 come from?

log(5.3E-7/1.2E-6)/log(0.0067/0.0133)=1- BrO3-
log(5.3E-7/2.8E-6)/log(0.0067/0.0200)=1.5- BrO3-
log(1.2E-6/2.8E-6)/log(0.0133/0.0200)=2- BrO3-
log(5.3E-7/2.02E-6)/log(0.0167/0.0333)=2- H
log(5.3E-7/3.8E-6)/log(0.0167/0.0500)=2-H
log(2.02E-6/3.4E-6)/log(0.0333/0.0500)= 1 H

Since you have 3 points for both of these, that's the minimum needed for linear regression.

Try graphing log[x] vs log(rate) and find the best straight line to fit the data.

 

[DeeNos]

As a scientist, it is important to understand that the order of reactants in a reaction is not always straightforward and can be affected by various factors. In this case, it seems that your teacher has already informed you that there may be discrepancies in the calculated orders. This could be due to experimental errors, uncertainties in the data, or other factors that may affect the reaction rate.

To determine the correct order of reactants, it is important to consider the overall trend of the data and not just focus on one or two data points. Additionally, it may be helpful to compare your results with other groups in the class or consult with your teacher for further guidance.

In terms of the calculations you have provided, it is difficult to determine the correct order of each reactant without knowing the specific details of the experiment and the data collected. It is also important to note that the orders are not always whole numbers and can be fractions or even negative values.

In conclusion, it is important to approach this problem with a critical and analytical mindset, considering all the factors that may affect the reaction rate. Consult with your teacher and classmates, and carefully analyze the data to determine the most accurate order of reactants.