Avogadro's constant, defined as \(6.022 \times 10^{23}\) entities (atoms, molecules, etc.) per mole, is named after the Italian scientist Amedeo Avogadro, who proposed the idea that equal volumes of gases, at the same temperature and pressure, contain an equal number of molecules. However, Avogadro himself did not calculate the actual value of this constant.
The value of Avogadro's constant was determined through various experiments, particularly in the early 19th century. One significant contribution came from the work of Johann Wolfgang Döbereiner and later from the experiments of Stanislao Cannizzaro, who in 1860 provided a clearer understanding of atomic weights.
The first accurate value of Avogadro's number was calculated in the late 19th century, primarily through the work of scientists like Jean Baptiste Perrin, who in the early 1900s calculated the value using methods involving Brownian motion. More precise measurements and calculations were refined over time, leading to the value we use today.
In summary, while Avogadro's name is associated with the constant, it was actually determined through the collective efforts of several scientists, with significant contributions from Perrin in the early 20th century.
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