Suppose you were calibrating a 25.0 mL volumetric flask using distilled water.

Question

Suppose you were calibrating a 25.0 mL volumetric flask using distilled water. The flask temperature was at 20 °C , and you assumed that the distilled water was as well. However, you later discover that the actual water temperature was 11 °C instead.

How is the mass of the 25.0 mL of distilled water you measured at 11 °C different from the mass of 25.0 mL of distilled water at 20 °C ?

A. It has the same mass as the water at 20 °C .

B. It is less than the mass of water at 20 °C .

C. It is greater than the mass of water at 20 °C .

If the masses are different, is the error in mass due to the temperature difference a systematic or random error?

A. It is both a systematic and random error.

B. It is neither a systematic or random error because the masses are the same.

C. It is a systematic error.

D. It is a random error.

Answer 1

How is the mass of the 25.0 mL of distilled water you measured at 11 °C different from the mass of 25.0 mL of distilled water at 20 °C ?

A. It has the same mass as the water at 20 °C .

B. It is less than the mass of water at 20 °C .

C. It is greater than the mass of water at 20 °C .

If the masses are different, is the error in mass due to the temperature difference a systematic or random error?

A. It is both a systematic and random error.

B. It is neither a systematic or random error because the masses are the same.

C. It is a systematic error.

D. It is a random error.

Systematic error is consistent thus in this case, there won't be change in mass at all, if the mass changes, then must be random error which can originate from the scale! Imagine struggling to read water meniscus twice or four times, chances that the values you get each time are same are minimal! These types of errors are random and are unavoidable.