Measuring Precisely

Poor precision in scientific measurement may arise from

• the standard being too strict.

• human error.

• limitations of the measuring instrument.

• both human error and the limitations of the measuring instrument.

Four students each measured the mass of one 1.43 g sample four times. The results in the table above indicate that the data collected by ______ reflect the greatest accuracy and precision.

• Student A

• Student B

• Student C

• Student D

• accurate but not precise

• precise but not accurate

• both accurate and precise

• neither accurate nor precise

• accurate but not precise

• precise but not accurate

• both accurate and precise

• neither accurate nor precise

• accurate but not precise

• precise but not accurate

• both accurate and precise

• neither accurate nor precise

A measurement that closely agrees with the accepted values is said to be ________________.

• accurate

• precise

• error

• limited

___________ is a measure of how close a series of measurements are to one another.

• Accurate

• Precise

• Error

• None of the above

Determine the density of an object that has a mass of 149.8 g and displaces 12.1 mL of water when placed in a graduated cylinder.

• 12.4 g/mL

• 11.4 g/mL

• 1.38 g/mL

• 8.08 g/mL

How many significant figures are in 1009.630 mL?

• 3

• 4

• 6

• 7

Read the length of the metal bar with the correct number of significant figures.

• 15

• 15.1

• 15.10

• 20