II-2 Group 2 A french Chemist: Joseph Proust

1754-1826

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Campanilla, Krisha

Cinco, Sam

Concepcion, Pia

Cruz, Gabrielli

Cruz, Jayrene

Life

Joseph L. Proust was born on September 26, 1754 in Angers, France. His father served as an apothecary in angers. Joseph studied chemistry in his father's shop and later came to Paris where he gained an appointment of apothecary in chief to the Salpetriere. He taught chemistry with Pilate de Rozier, a famous astronaut.

In His 30's, through the influence of Carlos IV, Proust moved to Spain, where he would spend most of his working life. There, he taught chemistry in several universities. While in Spain, he studied sugar but when Napoleon invaded Spain, they burned Proust's laboratory and forced him back to France. He died on July 5, 1826 in Angers, France
 

HISTORICAL TIMELINE OF JOSEPH PROUST

1774- Proust left for Paris, against his family's wishes and apprenticed himself to another pharmacist.
1776- He had won a position at a Paris hospital, where he worked as a chemist and pharmacist while lecturing at the Royal Palace.
1778- Proust went to Spain, having obtained the post of chemistry professor.
1780- He returned to France and stayed there for five years; during this time he taught chemistry and experimented with the new scientific sport of ballooning..
1785- Proust accepted a lucrative teaching position offered by the Spanish government. He spent the next twenty years in Spain at various posts in Madrid and Segovia, thus missing the French Revolution and the rise to power of Napoleon Bonaparte (1769-1821).
1799- When the chemical laboratories of Segovia and Madrid were merged, Proust became director of the new, lavishly equipped facility. While there, Proust published his law of constant composition, which later evolved into the law of definite proportions. At the time, most chemists agreed with Claude Berthollet, who believed the composition of a compound would vary according to the amounts of reactants used to produce it. In contrast, Proust proposed that pure reactants always combine in the same proportions to produce exactly the same compound.

For about eight years, Proust and Berthollet engaged in a friendly controversy over this issue, but, in the end, Proust was proved to be right. Berthollet had used impure reactants in his experiments, and thus he had analyzed the products inaccurately. Meanwhile, John Dalton had been formulating his atomic theory which was published in 1808. In this theory, Dalton rephrased Proust's law, calling it the law of multiple proportions. Although it is unclear whether Dalton was directly influenced by Proust, the law of constant composition provided evidence for Dalton's atomic theory, which in turn provides an explanation for Proust's observations.

Law of Definite Proportions

Proust's largest accomplishment into the realm of science was disaproving Berthollet with the law of definite proportions. Proust studied copper carbonate, the two tin oxides, and the two iron sulfides to prove this law. He did this by making artificial copper carbonate and compairing it to natural copper carbonate. With this he showed that each had the same proportion of weights between the three elements involved.
 

Sugar

Proust was also interested in studying sugars that are present in sweet vegetables and fruits. In 1799, Proust demonstrated how the sugar in grapes is identical to that found in honey. This later became known as glucose. Overall, Proust discovered three types of sugar.
 
TEXT FROM:
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