If a 0.5-mL air bubble is present in the tip of a buret, what percent error in 10-mL, 20-mL, and 40-mL samples will be result if the air bubble is dislodged during the dispensing of the samples?
(0.5/10)*100 = ??%
(0.5/20)*100 =
(0.5/40)*100 =
The point to the question is to show you that you need to titrate samples so that as much of the titrant that can be used is used. That isn't always possible. What can be done, and I have done it several times in my career, is to titrate an unknown sample, find that the replicates (I usually did at least 3) are low in the percent X and used only 10 or 15 mL from the buret. Two possibilities are (1) dilute the titrant so that it takes more (2)use more of the unknown so the titrant will be more. Again, the idea is to use 40 or 45 mL of titrant so that the reading error and the other errors of the same kind will be mimimized.
5%, 2.5%, 1.25%
To determine the percent error that may result from a dislodged air bubble in the buret, we need to calculate the volume of the air bubble relative to the volume of each sample.
Let's consider the three sample sizes: 10 mL, 20 mL, and 40 mL.
1. For the 10 mL sample:
If a 0.5 mL air bubble is dislodged during the dispensing of the sample, it will result in an error of 0.5 mL relative to the expected volume of 10 mL.
To calculate the percent error, we divide the error by the expected volume and multiply by 100:
Percent Error = (Error / Expected Volume) x 100
Percent Error = (0.5 mL / 10 mL) x 100
Percent Error = 5%
Therefore, the percent error for the 10 mL sample will be 5%.
2. For the 20 mL sample:
Using the same calculation, the percent error for the 20 mL sample can be determined as follows:
Percent Error = (0.5 mL / 20 mL) x 100
Percent Error = 2.5%
Therefore, the percent error for the 20 mL sample will be 2.5%.
3. For the 40 mL sample:
Again, applying the calculation, the percent error for the 40 mL sample can be calculated as follows:
Percent Error = (0.5 mL / 40 mL) x 100
Percent Error = 1.25%
Therefore, the percent error for the 40 mL sample will be 1.25%.
In summary, the percent errors resulting from a dislodged 0.5 mL air bubble in the buret during the dispensing of 10 mL, 20 mL, and 40 mL samples are 5%, 2.5%, and 1.25% respectively.
To calculate the percent error caused by the presence of a 0.5-mL air bubble in the tip of a buret, we need to determine how much this volume would affect the measured volumes of 10 mL, 20 mL, and 40 mL samples.
First, let's consider the effect on a 10-mL sample. If the air bubble is dislodged during dispensing, it would be included in the measured volume, leading to an error of +0.5 mL. To calculate the percent error, we divide the error by the measured volume and multiply by 100:
Percent error = (0.5 mL / 10 mL) * 100 = 5%
Similarly, for a 20-mL sample, the error would still be +0.5 mL. So, the percent error would be:
Percent error = (0.5 mL / 20 mL) * 100 = 2.5%
For a 40-mL sample, the error remains +0.5 mL. Thus, the percent error is:
Percent error = (0.5 mL / 40 mL) * 100 = 1.25%
So, the percent errors in 10-mL, 20-mL, and 40-mL samples due to the presence of a 0.5-mL air bubble would be 5%, 2.5%, and 1.25%, respectively.