Accuracy refers to the freedom from error or mistake of a measuring device. How accurate is a volumetric flask as a measuring instrument?

1 Answer
Sep 4, 2016

Answer:

The accuracy of a volumetric flask depends on its capacity.

Explanation:

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Volumetric flasks come in two classes, and in sizes ranging from 1 mL to 6 L.

Class A flasks are used in analytical labs. They are more accurate and must be marked with the letter "A".

Class B flasks are used for educational work or whenever extreme accuracy is not required. Their volumetric tolerances must be within twice the specified Class A tolerances.

They must all be used at their calibration temperatures.

The specifications for some common capacities of Class A flasks are:

#"Capacity/mL"color(white)(m)"Tolerance/mL"color(white)(m)"Tolerance/%"#
#stackrel(———————————————————)(color(white)(mmm)25color(white)(mmmmmm)0.030color(white)(mmmmm)0.12)#
#color(white)(mmm)50color(white)(mmmmmm)0.050color(white)(mmmmm)0.10#
#color(white)(mml)100color(white)(mmmmmm)0.080color(white)(mmmmm)0.080#
#color(white)(mml)250color(white)(mmmmmm)0.12color(white)(mmmmmll)0.048#
#color(white)(mml)500color(white)(mmmmmm)0.15color(white)(mmmmmll)0.030#
#color(white)(mm)1000color(white)(mmmmmll)0.30color(white)(mmmmmll)0.030#

Note that the absolute tolerance increases, but the relative tolerance decreases, as the capacity increases.