Question

5. Why would a measurement be reported as 18.0 mL instead of 18 mL?​

Answer 1

A measurement may be reported as 18.0 mL instead of 18 mL to indicate that it is an exact or precise measurement, rather than an approximation. In scientific experiments or laboratory work, measurements are often reported with a certain number of significant figures, which reflect the precision of the measurement.

In this case, 18.0 mL has one decimal point and implies that the measurement was made to the nearest 0.1 mL, whereas 18 mL doesn't have a decimal point and implies that the measurement was made to the nearest mL.

Additionally, in some cases, the trailing zero after a decimal point is used to indicate the accuracy of the measurement and to make it clear that it is not a rounded number.

Answer 2

A measurement may be reported as 18.0 mL instead of 18 mL to indicate that it has been measured with greater precision.

The decimal point in 18.0 mL indicates that the measurement was taken to the tenths place, meaning that the actual measurement is between 17.5 mL and 18.4 mL. On the other hand, 18 mL implies that the measurement is between 17.5 mL and 18.9 mL.

Therefore, the use of the decimal point in this case is a way to indicate that the measurement has a higher degree of precision. It is used as a way to communicate that the measurement was taken with greater accuracy and that the number has been rounded to the nearest tenth.