Question

Recall that at 4°C, water has a density of 1.0000 g cm^-3.  However, at 20°C, water has a density of 0.9982 g cm^-3.  

A student is using a balance to determine the difference between the amount of water transferred using a volume from a 10 mL volumetric pipette compared to a 10 mL in a 50 mL graduated cylinder.  To do this, the student measures the mass of a beaker and then adds water from the volumetric pipette.  The student records both measurements on some scrap paper and puts the paper in their pocket.  Then, the student measures the mass of a beaker and then adds water from the graduated cylinder.  Both of the masses are recorded on a different piece of scrap paper.  The scrap paper is then put in the same pocket as the other mass.

The student returns to the bench and takes out the scrap paper to try to compare the accuracy, however, cannot remember which measurement is for which piece of glassware.  Below are the values recorded.  Infer which measurement is for the volumetric pipette and which is for the graduated cylinder.  Choose the answer with the best explanation.

The values recorded on the two scrap papers are as follows:

Mass beaker: 88.60 g

Mass beaker + water: 98.49 g

Mass beaker: 71.24 g

Mass beaker + water: 81.23 g

Select one:

a.


The mass on the top is likely from the measurement with the volumetric pipette and the mass on the bottom is likely from the measurement with the water from the graduated cylinder. This is because the measurement on the bottom is closer to the mass expected for 10.00 mL at 20 °C.

b.

The mass on the top is likely from the measurement with the volumetric pipette and the mass on the bottom is likely from the measurement with the water from the graduated cylinder. This is because the measurement on the top is closer to the mass expected for 10.00 mL at 20 °C.

c.

The mass on the bottom is likely from the measurement with the volumetric pipette and the mass on the top is likely from the measurement with the water from the graduated cylinder. This is because the measurement on the top is closer to the mass expected for 10.00 mL at 20 °C.

d.

The mass on the bottom is likely from the measurement with the volumetric pipette and the mass on the top is likely from the measurement with the water from the graduated cylinder. This is because the measurement on the bottom is closer to the mass expected for 10.00 mL at 20 °C.

Answer 1