Gravimetric analysis is a method in analytical chemistry to determine the quantity of analyte based on the mass of a solid. Example: Measuring the solids suspended in the water sample – Once a known volume of water is filtered, the collected solids are weighed.
The principle behind the gravimetric analysis is that the mass of an ion in a pure compound and can be determined. Later, used to find the mass percent of the same ion in a known quantity of an impure compound.
There are 4 fundamental types of gravimetric analysis. Of which, there are 2 common types involving changes in the phase of the analyte to separate it from the rest of a mixture, resulting in a change in mass.
If the methods are followed carefully, it provides exceedingly precise analysis. It is used to determine the atomic masses of many elements to six-figure accuracy. It provides a little room for instrumental error and does not require a series of standards for calculation of an unknown.
It usually provides only for the analysis of a single element, or a limited group of elements, at a time. Comparing modern dynamic flash combustion coupled with gas chromatography with traditional combustion analysis.
An ore is analyzed for the manganese content by converting the manganese to Mn3O4 and weighing it. If a 1.52g sample yields Mn3O4 weighing 0.126g, what would be the percent Mn3O3 in the sample? The percent of Mn?
%Mn2O3=0.125gMn3O4×3Mn2O32Mn3O4(gMn2O3/gMn3O41.52gsample×100%
=0.126g×[3(157.9)/2(228.8)]1.52g×100%=8.58%
%Mn=0.126gMn3O4×3MnMn3O4(gMn/gMn3O4)1.52gsample×100%
=0.126g×[3(54.94)/228.8]1.52g×100%=5.97%