Chemical reactions are the heart of chemistry. People have
always known that they exist. The Ancient Greeks were the firsts
to speculate on the composition of matter. They thought that it
was possible that individual particles made up matter.
Later, in the Seventeenth Century, a German chemist named
Georg Ernst Stahl was the first to postulate on chemical
reaction, specifically, combustion. He said that a substance
called phlogiston escaped into the air from all substances during
combustion. He explained that a burning candle would go out if a
candle snuffer was put over it because the air inside the snuffer
became saturated with phlogiston. According to his ideas, wood
is made up of phlogiston and ash, because only ash is left after
combustion. His ideas soon came upon some contradiction. When
metal is burned, its ash has a greater mass than the original
substance. Stahl tried to cover himself by saying that
phlogiston will take away from a substance's mass or that it had
a negative mass, which contradicted his original theories.
In the Eighteenth Century Antoine-Laurent Lavoisier, in
France, discovered an important detail in the understanding of
the chemical reaction combustion, oxigine (oxygen). He said that
combustion was a chemical reaction involving oxygen and another
combustible substance, such as wood.
John Dalton, in the early Nineteenth Century, discovered the
atom. It gave way to the idea that a chemical reaction was
actually the rearrangement of groups of atoms called molecules.
Dalton also said that the appearance and disappearance of
properties meant that the atomic composition dictated the
appearance of different properties. He also came up with idea
that a molecule of one substance is exactly the same as any other
People like Joseph-Lois Gay-Lussac added to Dalton's
concepts with the postulate that the volumes of gasses tha...