a student used a 25 ml bulb pipette to deliver an aliquot of glucose solution in
ID: 496703 • Letter: A
Question
a student used a 25 ml bulb pipette to deliver an aliquot of glucose solution into a flask. The inherent uncertainty associated with the pipette was etched on
the glass ((+or-)0.02). he noted down the volume of the aliquot as "25 (+or-) 0.02 ml". what did he do wrong?. How should he have recorded the measurment?
b) A student was using 100-mL beaker to measure out twenty millilitres of solution. He was so inspired by your previous correction, that he reported the volume delivered by the beaker as "20.00(+or-) 0.05mL" is this the correct approach?
Explanation / Answer
(a)
The reading is wrongly recorded. It should be written as 25.00 (+ or -) 0.02 mL
(b)
The approach is not correct. The beaker has not been used upto its capacity, and it has been used to measure only 20 mL. 100 (+ or -)0.05 mL would have been correct for this beaker, but 20.00(+or-) 0.05mL is not.
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