The History of Chemistry

We learn of the various quantum numbers that describe the size and shape of the energy levels that electrons have inside atoms. Then Louis de Broglie proposes that, just as light has particle characteristics, matter (including electrons) have wave characteristics, which Davisson, Germer, and Thomson show is true. From this, we find that electron waves can fit around atoms only in certain energies....

This episode introduces us to the first attempts at "plastic materials" in the 19th century, from vulcanized rubber by Charles Goodyear and Thomas Hancock, to Alexander Parkes's "Parkesine", the first synthetic polymer. Later polymers of the Victorian era include Celluloid, rayon, photographic film and the rise of easy photography, the mostly forgotten charmer of the Art D...

We learn about the successes in finding structures for biochemical compounds like chlorophyll, steroidal molecules and bile acids, cholesterol, vitamin D, and bufotoxin. Other vitamins which were analyzed were vitamin A and vitamin B6. B6 has a pyridine structure. Chemists came to understand terpenes, found in places like pine trees. The blood molecule hemin has a similar structure to chlorophyll....

Charles Barkla realized how electrons arrange themselves in shells around atoms. Gilbert Lewis noted how electrons can pair up and form bonds, without (much) regard for willingness to give up or accept other electrons to complete shells. We discuss polarity of molecules. Irving Langmuir promoted and expanded Lewis's ideas, adding that atoms like to form octets. Finally, we discuss various mod...

Ernest Rutherford discovered the basic structure of the atom. Then Max von Laue suggested diffracting x rays through crystalline layers and showed that atoms have a particular arrangement in crystals. Henry Moseley found a relationship between scattered x rays off elements and the positive charge in their nucleus, thus explaining the Periodic Table. Then Max Plank upended science with his "qu...

Wilhelm Konrad Röntgen made an earth-shattering discovery for chemistry and atoms in 1895: He discovered x rays. Then, soon after, Henri Becquerel took the idea of x rays a step further and made another, equally earth-shattering discovery for chemistry and atoms: radioactivity. The Curies figured out which known elements were radioactive. Rutherford categorized radioactive rays into alpha, beta, a...

We finally reach the discovery of electrons. The path starts with experiments on electricity in small vacuum vessels and vacuum pumps, improved by Heinrich Geissler, further improved by William Crookes, and then proving that their mysterious cathode rays were matter, not light, responding to electric and magnetic fields and possessing a mass, as J.J. Thomson showed. Robert Millikan determined the...

In the 19th century, the centuries-old dependence on gunpowder for war began to change with Christian Schönbein's invention of guncotton. Then Sobrero invented the frightening nitroglycerin. We learn about Alfred Nobel's dealings with nitroglycerin and his efforts to improve its stability. We also hear about his will, founding the Nobel Prizes. There are more variations of nitro compound...

We examine industrial inorganic chemistry of the 18th and 19th centuries, including sodium carbonate, focusing on the Leblanc Process and its replacement, the Solvay method. We look at production of the number one chemical in the world, sulfuric acid. We discuss the superphosphate process for fertilizer, and the invention of the match. Steel was a major factor in the Industrial Revolution, so we e...

We look at the synthetic dye industry of the 1700s and 1800s, starting with Johann Diesbach, who invented Prussian blue in around 1706. Peter Woulfe found picric acid, a brilliant yellow compound, to be an effective dye for silk and wool in 1771. We hear the words of Dr. Jim Brazell, Professor Emeritus of English at The College of New Jersey, on early 19th-century literature by the German polymath...

In this episode we review 19th-century photochemistry, particularly photography, as well as chain reactions catalyzed by light. We finish up with boiling-point elevation, the last of the "colligative properties." With these aspects of physical chemistry, 19th-century physical chemistry gelled into a full chemical field, and the journal Zeitschrift für Physikalische Chemie was born. Suppo...

Josiah Gibbs revolutionized physical chemistry with his mathematics of thermodynamics and chemical equilibria, but published in an obscure journal few read. Wilhelm Ostward explained catalysis with his idea of an intermediate. Einstein figured out the cause of Brownian motion, and gave sufficient proof of atoms and molecules that all scientists accepted atomic theory. These developments led to the...

The Maxwell-Boltzmann distribution explains the behavior of gases nicely, and went well with the Ideal Gas Law of Clapeyton, until van der Waals modified the Ideal Gas Law a bit. We learn about absolute temperature and Lord Kelvin. Van 't Hoff connects the gas laws to osmotic pressure and ionic solutions. We hear of Raoult's Law and freezing-point depression. Finally we arrive at Svante...

We begin to examine 19th-century physical chemistry with thermodynamics. We hear of Rudolf Clausius and the two Laws of Thermodynamics, as well as entropy. There is Hess's Law, and Berthelot's calorimeter. We hear how Alexander Williamson started the field of chemical kinetics. Waage and Guldberg propose the Law of Mass Action, which tells us what concentrations of chemicals are at equil...

We learn about the development of spectroscopy by Bunsen and Kirchhoff, and its ramifications, like remote sensing of materials--including heavenly bodies. We also learn about new elements discovered by spectroscopy, which boosted Mendeleev's periodic table and earned him accolades. Mendeleev, however, also predicted elements that don't exist, and failed to anticipate an entire classific...

The problem of the large and growing variety of elements perplexed chemists, who attempted to bring order to the chaos. We learn about Döbereiner's triads, Pettenkofer and Dumas's correlations of multiples of atomic weights, Newlands's Law of Octaves, and Chancourtois's Telluric Screw. Kekulé's Karlsruhe conference brought order to some chemical chaos, and was the launchin...

...in which we learn how polarized light helped Louis Pasteur to determine that internal three-dimensional structure of molecules was real based on "optical isomers." We then move to the 1870s, and see how van 't Hoff and Le Bel independently came up with the idea of tetrahedral carbon to explain optical isomers. Once the idea of an actual 3D structure for molecules was accepted, a...

Edward Frankland realizes that there are specific valences for atoms. Archibald Scott Couper and August Kekulé simultaneously realize that specific atoms bond to specific other atoms in molecules, particularly carbon with valence 4, and invent ways of drawing this on paper. Kekulé also solved the problem of bonding within the compound benzene, after (so he later told it) a dream. My supporters at...

This episode explains how I create each episode of the podcast, from researching, to script-writing, recording, and editing. Support the show Support my podcast at  https://www.patreon.com/thehistoryofchemistry Tell me how your life relates to chemistry! E-mail me at steve@historyofchem.com Get my book, O Mg! How Chemistry Came to Be , from World Scientific Publishing, https://www.worldscientific....

We learn about Jane Marcet, one of the most popular science writers of the 1800s, and her connection to Michael Faraday, one of the most brilliant experimental scientists and demonstrators of the 1800s, as well as Faraday's investigations into electrochemistry. Faraday asked Reverend William Whewell for electrochemical terminology. We hear about the development of electric batteries, electrop...

We learn about radical theory and type theory in organic chemistry of the 2nd quarter of the 19th century, and the battle between old stalwart Berzelius and the upstart chemists Gerhardt and Laurent. There is a bit of political history from Japan, the Chōshū Five, and their intersection with English chemistry professor Alexander Williamson. Support the show Support my podcast at  https://www.patre...

We reach the beginning of the branch of chemistry called Organic Chemistry. How did organic chemistry differ from inorganic chemistry? Can chemists make organic compounds, or is that restricted only to living creatures? We learn about Friedrich Wöhler, and of Berzelius's theory of radicals, and the problem of isomers. Support the show Support my podcast at  https://www.patreon.com/thehistoryo...

In which we discuss Jöns Jakob Berzelius and his work. We also take a short detour to hear what US Presidents John Adams and Thomas Jefferson thought about chemistry. We mention the first female Swedish chemist, Anna Sundström. We continue with the conundrum of atomic weights, but the rule of Dulong and Petit helps this to a degree. Support the show Support my podcast at  https://www.patreon.com/t...

John Dalton, a Quaker from northern England, was a color-blind scientist. He presented his atomic theory that finally began to make sense to natural philosophers. He also invented a series of symbols for the elements, and created the first table of atomic weights. We learn about Joseph Prout's unusual atomic idea, and Gay-Lussac's work with gases that meshed with atomic theory. Then Ales...

What happened to Joseph Priestley and Marie-Anne plus Antoine Lavoisier? What were the immediate effects of Lavoisier’s new chemistry? We discuss how quickly the new chemistry was accepted, with some evidence in Elizabeth Fulhame’s book, plus the controversy between Berthollet and Proust over chemical composition of substances. Support the show Support my podcast at  https://www.patreon.com/thehis...