Antoine Lavoisier, son of a wealthy lawyer, was a social climber, tax collector and widely held to be the founder of modern chemistry. He was born in 1743 and was put to guillotine in 1794 on the charges of selling the adulterated tobacco which was a luxury and was very costly. It came from colonies in South America established by Europeans and employed black people as captives.
He discovered oxygen gas and named it so. Joseph Priestly, English scientist had also discovered this gas but named it “dephlogisticated air“. Both knew that the gas was closely associated with combustion in or around 1774. Priestly even demonstrated the synthesis of the gas by heating the mercury oxide with focused sun rays before Lavoisier when the former was a guest of the latter’s family on a tour to France. After some time of this event, Lavoisier also synthesized oxygen by an entirely different method.
He also demonstrated that water which was considered an element to be made of two elements oxygen and hydrogen. He devised a very brilliant method to split the water into its forming elements. The water was boiled and steam was passed through a coiled pipe made of iron. The box containing the coil was joined to another pipe which was dipped into the water at other end. The steam reacted with iron forming oxide thus subtracting the oxygen from water. Another component, namely Hydrogen, went out and bubbled through water and was collected by displacement above water.
Similarly he showed that air which again was considered an element was in fact a mixture of gases. He is also credited with starting the nomenclature of the elements known during his time. He even put the heat also among the elements list. He is thus responsible for initiating the process of documentation of chemistry.
His another great achievement was what is now known as Stoichiometry in chemistry. It is in a way is conservation of mass. He decomposed the salts of known weight and weighed the products and found that total amount remains the same. This audit of the mass has been responsible for the discovery of new compounds and elements and research chemists regularly make use of the this technique to pinpoint the missing mass.
Such a great scientist met with a very sad end. He was hanged when he was barely 50 years old.