18th century chemistry


The 1700s was the age for new discoveries.  Benjamin Franklin (1706-1790) introduced the idea of expressing electric charge as a result of gained or lost ‘electricity’, later defined as the electron.  This was inspired by Charles Francois de Cisternay du Fay (1698-1739), who proposed ‘positive’ and ‘negative’ charge.  Alessandro Volta (1745-1827) then made the first electric battery and electric current, which became the origin of electrochemistry, and suggested that electricity governed chemical reactions in some way.

The mid 1700s also saw the discovery of many new metals, including cobalt in 1730 by George Brandt (1694-1768) and nickel in 1751 by Axel Fredric Cronstedt (1722-1765), which shaped a new interest in what is now known as the transition metals.



A further breakthrough in chemistry was the discovery in the 1770s of nitrogen, hydrogen and oxygen, by Daniel Rutherford (1749-1819), Henry Cavendish (1731-1810) and Joseph Priestly (1733-1806) (see left) respectively.  This was fundamental to biological chemistry.  


Priestly: image reproduced from http://dbhs.wvusd.k12.ca.us/gallery/html


In addition, Cavendish’s most significant experiment was burning hydrogen to form water vapour.  Thus since water was now shown to be a combination of two gases, the Greek theory of the Elements had finally been disproved after an astonishing 2400 years!

Perhaps the most influential chemist of the century was Antoine Laurent Lavoisier (1743-1794) (see right), who theorized about many subjects, most notably recognizing the need for accurate and systematic measurements in chemistry, the discovery that diamond was a carbon analogue, and of course defining the concept of the conservation of mass.  Later in 1789 he devised a list of the 33 known elements.  Lavoisier had incorrectly included heat and light in this list, and a further 8 were later found to be compounds, however he had inspired a great many chemists to organize their findings, a quality which would later lead to the classification of elements into periods and groups to form the periodic table.



Lavoisier: image reproduced from http://dbhs.wvusd.k12.ca.us/gallery/html


19th century chemistry

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