Estimating Error in Titration Results Using Second Derivative Analysis

In summary, the error in each data point propagated to the x intercept of the graph, which needs to be taken into account when determining the error.
  • #1
bb1
5
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I have an error analysis question...I carried out a titration, and I have error for each measurement, but I then took the second derivative of the data and graphed it. The actual value I am reporting was estimated from the x-intercept of this graph. The curve was not fit to anything. How do I find the error to report with this value? Or do I not report error because it was estimated from a graph?
 
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  • #2
bb1 said:
I have an error analysis question...I carried out a titration, and I have error for each measurement, but I then took the second derivative of the data and graphed it. The actual value I am reporting was estimated from the x-intercept of this graph. The curve was not fit to anything. How do I find the error to report with this value? Or do I not report error because it was estimated from a graph?

You may need to consider error propagation , are you in college?

You may manipulate the axes to find the zero point more accurately , however , the sole error from this estimation is that of simply estimating between the left and right peaks and is similar to the procedure for measurement with a ruler. Are you using Excel?
 
  • #3
Thanks for responding...
Yes, I'm in college and I'm using excel...I have considered error propagation. The problem I'm having is that each volume measurement I have also has a random error from the measurement (0.02 ml in this case). When I calculated the "second derivative" (really I calculated the change in the change of pH against the average volume for the change) I also propagated error. However, when I graphed the second deriv, I estimated the x-intercept by inspection of the graph. What happens to the error I propagated? I feel like I can't really use it because I just calculated error for each point, and the x-intercept on the graph is not an actual measured point, so it seems wrong to me to use that error. It also seems wrong to just use the error of estimation from the graph. Do I somehow combine the error of my estimation with the propagation error? Does anything I'm saying make sense?
 
  • #4
bb1 said:
Thanks for responding...
Yes, I'm in college and I'm using excel...I have considered error propagation. The problem I'm having is that each volume measurement I have also has a random error from the measurement (0.02 ml in this case). When I calculated the "second derivative" (really I calculated the change in the change of pH against the average volume for the change) I also propagated error. However, when I graphed the second deriv, I estimated the x-intercept by inspection of the graph. What happens to the error I propagated? I feel like I can't really use it because I just calculated error for each point, and the x-intercept on the graph is not an actual measured point, so it seems wrong to me to use that error. It also seems wrong to just use the error of estimation from the graph. Do I somehow combine the error of my estimation with the propagation error? Does anything I'm saying make sense?

Your concerns are legitimate , the error for each data is going to have certain effects on the domain of the x intercept since it is propagated until the second derivative data - this means that each of the two peak points are going to have error bars which you are going to need to take into account of when determining the error off of simply estimating the x intercept between the peaks.

You should consider whether it is possible to find the error for just these two peaks , to do this you are probably going to need to take into account the maximum error in reading until that point e.g. if the error for each is 0.2 mL then after 5 mL it is 1 mL and after 10 it is 2 mL. After this consider the fact that derivatives take into account the rate for a particular point.

Should I find something useful I'm going to post it.
 
  • #5
What you're saying makes sense...thanks!
 

Related to Estimating Error in Titration Results Using Second Derivative Analysis

1. What is error analysis in titration?

Error analysis in titration is the process of identifying and quantifying the sources of error or uncertainty in a titration experiment. It involves evaluating the accuracy and precision of the measurements taken during the titration, as well as identifying any systematic errors that may have occurred.

2. Why is error analysis important in titration?

Error analysis is important in titration because it allows scientists to assess the reliability of their results and determine the validity of their conclusions. By identifying and quantifying the sources of error, scientists can improve the accuracy and precision of their measurements and ensure the validity of their experimental findings.

3. What are the common sources of error in titration?

Some common sources of error in titration include human error, such as improper technique or incorrect measurement readings, equipment error, such as faulty or malfunctioning equipment, and environmental factors, such as temperature or humidity fluctuations.

4. How do you calculate the percent error in titration?

The percent error in titration can be calculated by taking the absolute value of the difference between the experimental value and the accepted value, dividing it by the accepted value, and then multiplying by 100. The formula for percent error is: (|experimental value - accepted value| / accepted value) x 100.

5. How can errors in titration be minimized?

Errors in titration can be minimized by using proper technique and following the correct procedures, calibrating and maintaining equipment regularly, controlling environmental factors, performing multiple trials, and using appropriate data analysis techniques to identify and correct any systematic errors. It is also important to use high-quality reagents and to have a thorough understanding of the titration process.

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