Considering the various sources of error, would it be better (more accurate) to
ID: 574433 • Letter: C
Question
Considering the various sources of error, would it be better (more accurate) to volumetrically prepare 50 mL or 250 mL of a 0.01 M potassium dichromate solution? You may wish to consult the chart on page xxi of the manual.
If a buret reading were recorded as 25.6 mL, the absolute error would change to 0.2. How would this affect the relative error for this measurement?
A student calculated that 0.0006 g of material was needed to prepare a solution. Which of these recommendations would be appropriate?
Go ahead and make it
The student should buy a new balance that is accurate to the fifth decimal place.
The student should make a larger volume of the same concentration to have a larger mass
The student should make a more concentrated solution at the same volume to have a larger mass
A. 250 mL would be best, a larger mass has a lower relative error. B. 250 mL would be best because the relative error is smaller. C. 50 mL would be best, the smaller the mass the less error is likely. D. 50 mL would be best, a smaller volume has a smaller absolute error.Explanation / Answer
1st Question: Mass of potassium dichromate needed for 50ml=molarity*volume(in L)*molar mass=0.01M*0.050L*294g/mol=0.14g.Measuring such a smaill quantity accurately will be difficult and will have high chances of greater relative error.So its better to make large volume solution so that more mass can be dissolved which will be easy to measure.Thus answer is A.250 mL would be best, a larger mass has a lower relative error.
2nd Question:In burette relative error will have not impacted.So answer is D.
3rd.Answer is C. Similar reasoning as that for 1st question.
Comment in case of any doubt.