BCA
Semester II
Additional
English Notes
ANTOINE
LAVOISIER
1. When was Antoine Laurent Lavoisier born?
Ans) 26 August 1743
2. Where was Antoine Laurent Lavoisier born?
Ans) Paris
3. What did Antoine Laurent Lavoisier study for
three years but did not practice?
Ans) Law
4. When did Antoine Laurent Lavoisier join the
Academy of Sciences?
Ans) 1768
5. Which theory did Antoine Laurent Lavoisier
propound?
Ans) Oxygen theory of combustion
6. When did Antoine Laurent Lavoisier and his three
colleagues publish a new nomenclature of chemistry?
Ans) 1787
7. Of which firm was Antoine Laurent Lavoisier a
member?
Ans) General Farm
8. When was Antoine Laurent Lavoisier a director of
the French Gunpowder Administration?
Ans) 1775-1792
9. When did Antoine Laurent Lavoisier die?
Ans) 8 May 1794
10. How did Antoine Laurent Lavoisier die?
Ans) Guillotined
1. How did his wealth contribute to Lavoisier’s
success as a scientist, do you think?
Ans. Antoine Lavoisier was born with golden spoon as he belonged to wealthy family. He was fortunate to have the money with which he could buy the best equipment then available. Even he got enough share of money that was left by his mother, in the Tax Farm, a private company of financiers. He utilized his wealth to built his career and do experiment in laboratory.
2. How did his wife contribute to his success?
Ans. Madame Lavoisier was the wife of the chemist and nobleman Antoine Lavoisier, and acted as his laboratory companion and contributed to his work. She played a pivotal role in the translation of several scientific works, and was instrumental to the standardization of the scientific method. Paulze accompanied Lavoisier in his lab during the day, making entries into his lab notebooks and sketching diagrams of his experimental designs. The training she had received from the painter Jacques-Louis David allowed her too accurately and precisely draw experimental apparatuses, which ultimately helped many of Lavoisier's contemporaries to understand his methods and results.
3. To what was it that Stahl had given the name
‘Phlogiston’?
Ans. Phlogiston(a fire-like element which is gained or released during a material's combustion) was used to describe the apparent property changes that substances exhibited when burned.
4. What mistaken ideas had earlier chemists held
about the nature of air?
Ans. Chemists thought air was only gas in existence, and to be pure in its natural state. It was supposed that it could absorb ‘phlogiston’ from substances when they burned. Joseph Black had discovered the existence of a gas which he called ‘fixed air’ (carbon dioxide). Joseph Priestley had discovered ‘dephlogisticated air’ (oxygen) and Henry Cavendish had discovered ‘inflammable air’ (hydrogen).
5. What was Priestley’s strength as an experimental
chemist?
Ans. Joseph Priestley: The man who discovered Oxygen. One of the founding fathers of chemistry, Joseph Priestley (1733-1804) stumbled across photosynthesis, is credited with the discovery of oxygen and accidentally brought us soda water. In a series of experiments culminating in 1774, Priestley found that "air is not an elementary substance, but a composition," or mixture, of gases. Among them was the colorless and highly reactive gas he called "dephlogisticated air," to which the great French chemist Antoine Lavoisier would soon give the name "oxygen."
6. In what important respect was Lavoisier his
superior?
Ans. Lavoisier and Priestley are one of the great double acts in the history of science, inextricably entangled in the annals of history and the myths of chemistry by priority disputes over the discovery of oxygen and the revolutionary origins of modern chemistry. Underlying the overt scientific conflict between Antoine-the leader of the revolutionary ‘antiphlogistian’ party and Priestly- the lone defender of the phlogiston theory- was a shared commitment to the rational and liberal principles of the philosophies and the shared fate of social exclusion. Lavoisier on the guillotine and Priestly in exile-that befell them when they carried these ideals into the social and political arena, whereas Lavoisier’s advances ‘left Priestley behind’.
7. In what way did his simple, early experiments with phosphorus set Lavoisier on his chosen path?
Ans. As Lavoisier began his career as a chemist, he bought some phosphorus. He observed how it gave off white fumes when exposed to air; how it glowed green in the dark; and how, when it was burnt, it gave off a flame, and clouds of thick white smoke. More significantly, he observed that when he attached a bag of air to the neck of the vessel containing the burning phosphorous, a considerable volume of air passed form the bag into the vessel. The phosphorus itself appeared to take up the air as it burned. Just as Boyle had shown that a candle only burned for a limited period, in a limited amount of air, so Lavoisier found that only a part of the phosphorous would burn when the volume of air was limited.
8. Why did Lavoisier report the results of his first experiments, but enclose them in a sealed envelope?
Ans. Lavoisier conducted experiment with phosphorus and sulphur and found that anything being given off when the substance burned (as the phlogiston theory held), it took up an impressive quantity of air. This finding set him on the course that he would follow until his death. He did not publish it, but recorded it in a paper that he committed to sealed envelope. This he deposited at the Royal Academy of Sciences, with an instruction that it should be opened only when he gave the world. He was determined to be the first scientist to advance the theory that, on combustion, a substance absorbs large quantities of air; but he was equally determined to be absolutely sure that the theory was sound before he published it.
9. What grand objective did he set himself,
following his first experiments?
Ans. He was determined to be the first scientist to
advance the theory that, on combustion, a substance absorbs large quantities of
air; but he was equally determined to be absolutely sure that the theory was
sound before he published it.
10.Why was the calx of the metal, in fact, heavier
than metal from which it was formed?
Ans. A substance to more intense heat than had been possible before, it had long been known that when certain metals are melted, a waste product forms on their surface, called a calx. This calx, it had been discovered, was heavier than the metal from which it was formed. The explanation for this had been that the metal had given up its ‘phlogiston’ to the calx.
11.Why might what Priestly said to the Parisian
scientist, at Lavoisier’s house, have
surprised all present?
Ans. Priestly travelled in Europe with his patron
Lord Shelburne in the autumn of 1774. In October, he dined with Lavoisier and
his wife, and a number of Parisian scientists. In accordance with his open,
honest character he told the company all about his experiment, to the surprise
(as he related) of all present.
12.Why did a mouse die in the gas that Black had
called ‘fixed air’?
Ans. A mouse would die due to lack of air. The theory held that when a candle burned, for example, phlogiston was transferred from it to the surrounding air. When the air became saturated with phlogiston and could contain no more, the flame went out. Breathing, too, was a way to remove phlogiston from a body. A typical test for the presence of phlogiston was to place a mouse in a container and measure how long it lived. When the air in the container could accept no more phlogiston, the mouse would die due presence of fixed air (carbon dioxide).
13.How did it come to be that pure water resulted from the lighting of a mixture of “inflammable air” and “dephlogisticated air”?
Ans. When Priestley lit a mixture of Cavendish’s inflammable air and his own “dephlogisticated air”, in 1787, he noticed that drops of water were formed. When Cavendish repeated the experiment, he found that the amounts of inflammable air and “dephlogisticated air” that were turned to water were (approximately) in the ratio 2:1.
14.Why might Cavendish have published a report of
his experiments if only he had been able to look ahead?
Ans. Cavendish might have published a report of his experiments if only he had been able to look ahead then his assistant Blagden, wouldn’t visit Paris and wouldn’t described the experiment and what had happened to Lavoisier. His experiment would be patent in the name of Cavendish in Royal Academy rather than Lavoisier.
15.What does the Law of the Conservation of Mass
state, in simple terms?
Ans. When a substance undergoes chemical change, none of its mass is lost. We call this the Law of the Conservation of Mass.
