What is gravimetry?
What Does gravimetry Mean
The dictionary of the Royal Spanish Academy ( RAE ) recognizes different meanings of the term gravimetry . The concept can refer to the analysis of the gravitation of planet Earth and the measurement of its changes in different places.
The gravitation is the universal attraction of the bodies according to their mass (the amount that reflects the amount of matter). What gravimetry does, in this framework, is measure the gravitational field , also known as the gravitational field .
Gravity is generally measured in units of acceleration, such as meter per second squared . However, you can also use newtons per kilogram or use other units.
The device that uses gravimetry to develop its measurements is known as a gravimeter . It is an instrument that allows us to know the local gravitational field of the planet .
These gravimeters are accelerometers that record the downward acceleration of gravity. They usually have springs that produce an effect opposite to the force of gravity that affects the mass.
The notion of gravimetry, on the other hand, refers to the quantitative method that makes it possible to discover, when measuring its weight , a quantity of substance . Gravimetry, in this case, involves weighing the substance eliminating the presence of any other element that may interfere, and then developing an analytical calculation based on the molecular and atomic weights.
This is the so-called gravimetric analysis found in the framework of analytical chemistry . His object of study are samples, of which he tries to find out the amount of a radical, compound or element; For this, it not only eliminates interferences, but transforms the constituent into a compound that can be heavy.
The instrument used for this work is the analytical balance , and the results are highly accurate. To carry out the calculations, scientists in this field rely on atomic and molecular weights, knowing that pure substances are of constant composition and making use of stoichiometry , the calculation of the quantity relationships that occur between products and reactants in the context of a chemical reaction.
Gravimetric analysis uses more than one method , of which we can highlight the following three: by precipitation, by volatilization and by electrodeposition . The first is a classic technique that relies on the elaboration of a solid starting from a solution (which is known by the name of precipitation . Its chemical composition must be known to calculate the amount of analyte that was at the beginning of the sample; stoichiometric ratios are generally used to achieve this goal.
The volatilization method consists of measuring the components that are volatile , or those that may be. If the analyte is evaporated and passed through a heavy absorbent substance in advance, the method is said to be straightforward; if it is volatilized and the residue is weighed, on the other hand, it is indirect. The first gives us a weight gain that corresponds to the desired analyte, while the second gives us a weight loss equivalent to the volatilized analyte.
For the third, a compound is deposited on the electrode with the analyte whose quantity is to be known. The difference in the weight of the electrodes in the moments before and after a reduction-oxidation reaction in the solution, which is molded to cause the analyte or other compound that has it in its composition to precipitate.
Gravimetry is also the process that is applied to separate the gangue (the waste material) from the minerals through mechanical means. For this, we work with the different densities of the elements.