129 Fun Facts About Chemistry

Which chemist created the first widely accepted periodic table?

Dmitri Mendeleev, a Russian chemist, is credited with creating the first widely accepted version of the periodic table in 1869. He arranged the elements by atomic weight and predicted the properties of undiscovered elements.

Beyond solid, liquid and gas, what is usually counted as the fourth state of matter, the stuff of stars and lightning?

Plasma is an ionised gas of free electrons and ions that answers to electric and magnetic fields; William Crookes floated the idea of a fourth state in 1879.

What type of chemical reaction absorbs heat energy from its surroundings?

Endothermic reactions absorb heat energy from their surroundings, causing the temperature of the surroundings to drop and often feeling cold to the touch.

Which element, with atomic number 1, is the lightest on the periodic table?

Hydrogen, with atomic number 1, is the lightest and most abundant chemical element in the universe, consisting of a single proton and typically one electron.

What subatomic particle found in the nucleus of an atom carries a positive electric charge?

Protons are stable subatomic particles found in the nucleus of an atom, carrying a positive electric charge.

What is the chemical symbol for the element gold?

Au is the chemical symbol for gold, derived from its Latin name, aurum. Ag is silver, Fe is iron, and Pb is lead.

What is the common name for sodium chloride?

Sodium chloride (NaCl) is commonly known as table salt. Baking soda is sodium bicarbonate, table sugar is sucrose, and Epsom salt is magnesium sulfate.

Which element has an atomic number of 8?

Oxygen has an atomic number of 8, meaning each atom of oxygen has 8 protons in its nucleus. Nitrogen is 7, Fluorine is 9, and Carbon is 6.

What is the approximate pH of pure water at 25°C?

Pure water at 25 °C has a pH of 7: H⁺ and OH⁻ are both 10⁻⁷ mol/L, so it is neutral. Heated above 25 °C, the neutral point drifts below 7.

What type of chemical bond has atoms sharing electron pairs, the kind that holds a water molecule together?

A Covalent bond shares electrons; an ionic bond transfers them, a metallic bond pools them, and a hydrogen bond is just an attraction between molecules, the one that makes ice float.

Which functional group has a carbon double-bonded to oxygen and bonded to a hydrogen and an R group?

An aldehyde group (R–CHO) has its carbonyl carbon bonded to one hydrogen and one alkyl or aryl group; formaldehyde (HCHO) and acetaldehyde (CH₃CHO) are the simplest examples.

In a redox reaction, what term describes the loss of electrons by a chemical species?

Oxidation is defined as the loss of electrons, or an increase in oxidation state. Reduction is the gain of electrons.

Which reaction type has an acid and a base forming a salt and water?

Neutralization is the reaction of an acid with a base to give a salt and water; hydrochloric acid and sodium hydroxide yield sodium chloride and water (HCl + NaOH → NaCl + H₂O).

What is the typical oxidation number of an uncombined element?

An element in its free, uncombined form (e.g., O2, Fe, H2) has an oxidation number of 0.

Which characteristic is commonly associated with transition metals?

Transition metals are known for their ability to form compounds in multiple oxidation states and frequently produce brightly colored compounds due to d-d electronic transitions. They generally have high melting points and are good electrical conductors.

Which functional group contains a carbonyl group bonded to two other carbon atoms?

A ketone has its carbonyl (C=O) carbon bonded to two other carbon atoms, so the group sits inside the chain; acetone, CH₃COCH₃, is the simplest ketone.

An organic compound whose molecule carries a –COOH group belongs to which class?

A carboxylic acid is defined by the –COOH group; acetic acid in vinegar and citric acid in lemons are everyday examples, and the carbonyl stabilises the anion left when the –OH proton leaves.

Which functional group, formed from a carboxylic acid and an alcohol, has an R-COO-R' structure?

An ester has the R–COO–R′ structure and forms by esterification, the condensation of a carboxylic acid with an alcohol; ethyl acetate, from acetic acid and ethanol, is a familiar example.

What is the smallest unit of an element that retains the chemical properties of that element?

Atoms are the fundamental building blocks of all matter and are defined by their number of protons. They are the smallest units that maintain an element's distinct chemical identity.

Which gas makes up about 78% of Earth's atmosphere by volume?

Nitrogen (N₂) makes up about 78% of dry air by volume; oxygen is about 21%, argon just under 1%, and carbon dioxide roughly 0.04%.

A solution with a pH of 2 is considered what type of substance?

The pH scale ranges from 0 to 14, where values below 7 indicate acidity, values above 7 indicate alkalinity (basicity), and 7 is neutral.

Who is credited with the discovery of the electron?

His 1897 cathode-ray experiments showed the particles were far smaller than atoms; the electron was the first subatomic particle ever discovered, and Thomson won the 1906 Nobel Prize in Physics.

What is the primary chemical compound found in rust?

Rust is primarily hydrated iron(III) oxide, which forms when iron and oxygen react in the presence of water or air moisture.

Which group of elements, with full outer electron shells, sits in the table's last column and barely reacts with anything?

Noble Gases were left off Mendeleev's first table entirely, since none had been discovered; he added them as 'group 0' in 1902 once helium and argon were accepted.

Which branch of chemistry primarily studies compounds containing carbon-hydrogen bonds?

Organic chemistry is dedicated to the study of the structure, properties, composition, reactions, and preparation of carbon-containing compounds.

What is it called when a solid changes directly into a gas without becoming liquid?

Sublimation is an endothermic phase transition that occurs at temperatures and pressures below a substance's triple point.

Atoms of the same element with different numbers of neutrons, such as carbon-12 and carbon-14, are called what?

Isotopes share a proton count and a place in the table, which is what the name means, 'same place'; ions differ in electrons, allotropes in structure.

What term describes a substance that speeds up a chemical reaction without being consumed?

A catalyst speeds up a reaction without being consumed, opening a lower-energy pathway; the platinum in a car's catalytic converter is a familiar example.

What type of chemical reaction releases energy, often as heat or light?

Exothermic reactions have a negative enthalpy change (ΔH < 0), indicating that the products have lower energy than the reactants and the excess energy is released.

What type of hybridization does the carbon atom exhibit in a methane (CH₄) molecule?

In methane, the carbon atom undergoes sp³ hybridization, where one 2s and three 2p atomic orbitals combine to form four equivalent sp³ hybrid orbitals, resulting in a tetrahedral geometry.

Under the Arrhenius theory, an acid increases the concentration of which ion in aqueous solution?

The Arrhenius theory defines an acid as a substance that produces hydrogen ions (H⁺) in aqueous solution, which immediately combine with water to form hydronium ions (H₃O⁺).

Which allotrope of carbon is the hardest natural material known?

Diamond and graphite are the two most common allotropes of carbon; diamond packs more atoms per unit volume than any known substance, which is why it is both the hardest and least compressible.

What kind of solution holds its pH steady when small amounts of acid or base are added, as blood does?

A Buffer solution pairs a weak acid with its conjugate base, so either can mop up added H⁺ or OH⁻; blood's bicarbonate buffer holds it near pH 7.4.

What is the minimum energy reactants must have before a chemical reaction can occur?

Activation energy is why a match needs striking: wood and oxygen want to react, but they need a push over the barrier to the transition state first.

What are molecules with the same formula and bonding sequence but different 3D orientation of atoms called?

Stereoisomers exhibit the same connectivity but have different spatial arrangements of their atoms, leading to distinct chemical and physical properties.

What term describes the extra stability of complexes formed by polydentate rather than monodentate ligands?

The chelate effect is a thermodynamic phenomenon where polydentate (chelating) ligands form more stable complexes with metal ions due to a more favorable entropy change upon binding.

Which of these says a system in equilibrium shifts to counteract an applied change?

Le Chatelier's Principle is fundamental in predicting how chemical equilibria respond to changes in concentration, temperature, or pressure.

Which set of numbers describes the properties of atomic orbitals and the electrons within them?

Quantum numbers (principal, azimuthal, magnetic, and spin) define the size, shape, orientation, and spin of an electron in an atom.

Which family of organic compounds is defined by a hydroxyl group (-OH) attached to a saturated carbon atom?

Alcohol in chemistry is a whole family, and the drinkable one, ethanol, is just the two-carbon member; the word comes from the Arabic al-kuhl, the original kohl eyeliner.

Which constant, exactly 6.02214076 × 10²³ per mole, links an amount of substance to its number of particles?

Avogadro's number has been an exact figure since 2019, so a mole is now defined by counting particles rather than by the mass of carbon-12. Avogadro himself never calculated it.

Apart from mercury, which is the only element that is a liquid at standard temperature and pressure?

Bromine, a volatile red-brown halogen, is the only non-metal that is liquid at standard conditions and evaporates into a vapour of the same colour; gallium (29.8 °C) and caesium (28.4 °C) melt just above room temperature.

What is the chemical symbol for potassium?

K is the symbol for potassium, from its Neo-Latin name kalium; P is phosphorus, Po is polonium and Pt is platinum.

Which type of radioactive decay involves the emission of a helium nucleus?

Alpha decay is a type of radioactive decay in which an atomic nucleus emits an alpha particle (a helium nucleus) and thereby transforms or 'decays' into a different atomic nucleus.

What technique separates a mixture's components between a stationary phase and a mobile phase?

Chromatography separates a mixture by carrying it in a mobile phase over a stationary phase; Mikhail Tsvet coined the name in 1906 after separating plant pigments into coloured bands on a chalk column.

What process uses electrical energy to drive a non-spontaneous chemical reaction?

Electrolysis uses a direct electric current to force a non-spontaneous reaction; passing current through acidified water splits it into hydrogen at the cathode and oxygen at the anode.

Which industrial method synthesizes ammonia from nitrogen and hydrogen over an iron catalyst?

The Haber-Bosch process combines nitrogen and hydrogen over a finely divided iron catalyst at high pressure (150–250 atm) and around 450 °C; its ammonia feeds the fertiliser behind a large share of the world's food supply.

Which class of large molecules is built from repeating units, found in plastics and natural materials like DNA?

Polymers are large molecules composed of many repeated smaller units called monomers, and they are ubiquitous in both natural and synthetic materials.

What term refers to measuring the heat changes of chemical reactions or physical changes?

Calorimetry measures the heat absorbed or released by a reaction or phase change; a bomb calorimeter burns a sample in oxygen and reads the temperature rise of the surrounding water.

Which group-18 element has the highest atomic number?

Oganesson, element 118, sits at the bottom of group 18 and was named in 2016 for Yuri Oganessian; relativistic effects are predicted to make it a reactive solid, unlike the noble gases above it.

On the Pauling scale, which element has the highest electronegativity, at 3.98?

Fluorine tops the Pauling scale at 3.98; caesium sits near the bottom at 0.79, and that gap is why caesium fluoride is among the most ionic compounds known.

Which organomagnesium reagents, named for a 1912 Nobel laureate, are used to form carbon-carbon bonds?

Victor Grignard shared the 1912 Nobel Prize in Chemistry for the discovery; the compounds are so reactive with water that they must be prepared in dry ether.

What type of bond links amino acids together to form proteins?

A peptide bond is an amide type of covalent chemical bond linking two consecutive alpha-amino acids from C1 (carbon number one) of one alpha-amino acid and N2 (nitrogen number two) of another alpha-amino acid along a peptide or protein chain.

Which term describes elements with atomic numbers greater than 92?

Transuranic elements have atomic numbers above 92, uranium's; all are radioactive and, apart from traces of neptunium and plutonium, are made artificially. Neptunium (93), produced in 1940, was the first.

Which superacid, able to protonate hydrocarbons, is often called the strongest known acid?

Fluoroantimonic acid, hydrogen fluoride mixed with antimony pentafluoride, is many orders of magnitude stronger than pure sulfuric acid on the Hammett scale and can protonate hydrocarbons; it attacks glass, so it is stored in PTFE.

Which German chemist's 1828 synthesis of urea from an inorganic salt is cited as the birth of modern organic chemistry?

Friedrich Wöhler made urea from ammonium cyanate, but the textbook claim that this alone killed vitalism is overstated; Kolbe's 1845 acetic acid synthesis did more damage.

August Kekulé said he hit on the ring structure of benzene after a daydream about what?

Kekulé told the 1890 Benzolfest that a daydream of a snake seizing its own tail suggested the ring; he published the six-membered ring with alternating single and double bonds in 1865.

What is the general formula for the alkanes, the saturated hydrocarbons that begin with methane?

Their old trivial name is paraffins. Each extra carbon in the chain raises the boiling point by roughly 20-30 °C.

How many structural isomers does pentane, the five-carbon alkane, have?

They are n-pentane, isopentane and neopentane. Butane has just two, and the count explodes as chains get longer.

Which pair of German chemists shared the 1950 Nobel Prize for the cycloaddition that builds a cyclohexene ring in one step?

Diels and Alder first described their reaction in 1928; it forms two carbon-carbon bonds at once with predictable stereochemistry, which is why synthetic chemists love it.

Which 18-year-old accidentally made the synthetic dye mauveine in 1856 while trying to make quinine?

William Henry Perkin was oxidising aniline with potassium dichromate when the purple residue appeared; the mauve craze of 1859–61 made his fortune and launched the synthetic dye industry.

According to Markovnikov's rule, when HX adds to an unsymmetrical alkene, the hydrogen goes to which carbon?

Students remember it as 'the rich get richer'. Add a peroxide and the reaction flips to anti-Markovnikov via a radical mechanism, the Kharasch effect.

Which scientist discovered molecular chirality in 1848 by hand-sorting left- and right-handed tartrate crystals?

Louis Pasteur found that solutions of the two crystal forms rotated polarised light in opposite directions and correctly inferred that an asymmetric arrangement of the molecules themselves was responsible.

Which type of hydrocarbon contains at least one carbon-carbon triple bond, acetylene being the simplest?

Alkyne names end in -yne, alkenes with double bonds in -ene and single-bonded alkanes in -ane; acetylene's proper name is ethyne.

Which German chemist with a famed Giessen lab is a principal founder of organic chemistry?

Justus von Liebig trained a generation of chemists in his Giessen teaching laboratory from 1824, pioneered agricultural chemistry and mineral fertilisers, and lent his name to the Liebig condenser and to a beef extract.

Marie Curie won her 1911 Nobel Prize in Chemistry for discovering which two elements?

Marie Curie's 1911 chemistry prize cited the discovery of radium and polonium and the isolation of radium; she had shared the 1903 physics prize with Pierre Curie and Henri Becquerel for radioactivity.

Which chemist, who named oxygen in 1778, was guillotined during the French Revolution?

Antoine Lavoisier, a tax farmer under the old regime, was charged with tax fraud and adulterating tobacco and guillotined in Paris on 8 May 1794.

Which 17th-century book by Robert Boyle is regarded as a cornerstone of chemistry?

The Sceptical Chymist (1661) attacked the Aristotelian four elements and the alchemists' three principles, arguing that matter is made of corpuscles; Boyle's gas law followed a year later.

Joseph Priestley isolated oxygen in 1774 by heating which compound?

Joseph Priestley focused sunlight on mercuric oxide, the red calx of mercury, with a burning lens and collected the gas he called 'dephlogisticated air'; he had invented carbonated water in 1767.

Which chemist first isolated potassium and sodium in 1807 using electricity?

Humphry Davy isolated potassium and then sodium in 1807 by electrolysing molten potassium hydroxide and sodium hydroxide with a voltaic pile; the next year he added calcium, strontium, barium, magnesium and boron.

Which chemist discovered benzene in 1825 and popularised the terms 'anode' and 'cathode'?

Michael Faraday isolated benzene in 1825 from illuminating-gas residue; his 1834 electrolysis papers, with terms coined with William Whewell's help, gave us anode, cathode, electrode and ion.

Which Swedish chemist invented the system of letter symbols for the chemical elements?

Jöns Jacob Berzelius proposed the one- or two-letter Latin-based symbols in 1813, writing the numbers as superscripts where modern notation uses subscripts; he also discovered cerium, selenium, silicon and thorium.

Who in 1903 became the first Swedish Nobel laureate, winning the chemistry prize?

Arrhenius also produced an early greenhouse hypothesis about carbon dioxide.

Fritz Haber, who won the 1918 Nobel Prize for ammonia synthesis, is also called the father of what?

Fritz Haber is called the father of chemical warfare for personally directing the first chlorine attack at Ypres in April 1915; the ammonia process he won the Nobel for also underpins the fertiliser that feeds much of the world.

How many patents did Alfred Nobel hold during his life?

Alfred Nobel held 355 patents in his lifetime; the most famous, dynamite, was patented in 1867, and the fortune they built endowed the Nobel Prizes.

Glenn Seaborg was principal or co-discoverer of how many elements?

Glenn Seaborg was principal or co-discoverer of ten elements, plutonium (94) through nobelium (102) plus seaborgium (106), which was named for him in 1997, two years before his death.

Which X-ray crystallographer has been called the 'dark lady of DNA'?

Rosalind Franklin died in 1958 at 37, four years before the Nobel for DNA went to Watson, Crick and Wilkins; her work on coal and viruses was the part recognised in her lifetime.

Frederick Sanger won his first Nobel Prize in 1958 for sequencing which protein?

Frederick Sanger's 1958 prize was for determining the full amino-acid sequence of insulin, the first protein sequenced; his second, in 1980, was for the dideoxy method of DNA sequencing.

Bunsen and Kirchhoff discovered which two elements using spectroscopy in 1860–61?

Bunsen and Kirchhoff found caesium (1860) and rubidium (1861) in Dürkheim mineral water by their spectral lines, naming them for the sky-blue and deep-red lines; Bunsen built his famous burner with Peter Desaga.

Whose X-ray work justified the concept of atomic number before he died at Gallipoli in 1915?

Moseley's law showed atomic number, not atomic weight, orders the periodic table.

Neon was discovered in 1898 alongside which two other noble gases?

Ramsay and Travers found krypton and xenon in the same 1898 campaign, fractionating liquefied air; neon's bright red emission spectrum identified it at once. Argon (1894) and helium (1895) came earlier.

The Hall–Héroult process of 1886 made which metal widely available?

Charles Martin Hall and Paul Héroult independently developed the electrolysis of alumina dissolved in molten cryolite in 1886, turning aluminium from a precious metal into a cheap one.

Which element makes up about 28% of Earth's crust by mass, second only to oxygen?

Silicon makes up about 28% of the crust by mass, nearly all of it bound with oxygen in silicate minerals and quartz; Berzelius first prepared it in pure form in 1823.

Hennig Brand discovered phosphorus in 1669 while experimenting with what?

Hennig Brand, hunting for the philosopher's stone, boiled down vast quantities of urine and got a waxy solid that glowed in the dark; the name phosphorus means 'light-bearer' in Greek.

Chlorine's name comes from a Greek word meaning what?

Davy named chlorine in 1810 from the Greek chloros, 'pale green', for the gas's colour, after confirming it was an element; Scheele had first described it in 1774.

Which noble gas takes its name from the Greek for 'lazy' or 'idle'?

Argon comes from the Greek argos, 'idle', because Rayleigh and Ramsay, who isolated it in 1894, could not make it react with anything; krypton means 'hidden', neon 'new' and xenon 'stranger'.

Which metal has the highest electrical conductivity of any element?

Silver has the highest electrical conductivity of any element, about 63 million S/m at 20 °C, just ahead of copper; its symbol Ag comes from the Latin argentum.

What is the sound made when a bar of tin is bent called?

The tin cry is the creaking sound a bar of tin makes when bent, produced as the metal's crystals twin under deformation; indium makes the same noise.

Iodine was named by Gay-Lussac after the Greek word for which colour?

Gay-Lussac named iodine in 1813 from the Greek iodes, 'violet-coloured', for its vapour; Bernard Courtois had discovered it in 1811 while extracting saltpetre from seaweed ash.

Which element has the highest melting point of any metal, at 3,422 °C?

Tungsten melts at 3,422 °C, the highest of any metal, which is why it served as the incandescent-lamp filament; its symbol W comes from wolfram, after the ore wolframite.

The word platinum comes from Spanish 'platina', meaning what?

Platina is Spanish for 'little silver', a diminutive of plata, because the Spanish in Colombia took the metal for a nuisance form of silver; Antonio de Ulloa reported on it in 1748.

Which planet, first sighted by William Herschel in 1781, gave element 92 its name?

Martin Heinrich Klaproth, who found element 92 in pitchblende in 1789, named it uranium after Uranus, the planet William Herschel had discovered eight years earlier.

Polonium was the first element discovered by which method?

Polonium was the first element found by tracking its radioactivity: the Curies traced the excess activity of pitchblende to a new element in July 1898 and named it for Marie's native Poland.

Which element, found by Marguerite Perey in 1939, was the last discovered in nature, not by synthesis?

Francium, found by Marguerite Perey in 1939 as a decay product of actinium, was the last element first discovered in nature rather than by synthesis; it is the second rarest natural element after astatine.

Which element, produced in 1937, was the first predominantly artificial element?

Technetium, element 43, was made in 1937 by bombarding molybdenum with deuterons in Lawrence's cyclotron; Perrier and Segrè identified it in Palermo and named it from the Greek technetos, 'artificial'.

Which metal, discovered by Lecoq de Boisbaudran in 1875, melts in the palm of your hand?

Unlike mercury, liquid gallium wets glass and skin.

Which element, predicted by Mendeleev as eka-silicon, was discovered in 1886?

Germanium was isolated by Clemens Winkler in Freiberg in 1886 from the mineral argyrodite and named for his homeland; its properties matched Mendeleev's 1871 prediction for eka-silicon almost exactly.

Titanium was discovered in 1791 in which English county?

The clergyman William Gregor found the new metal in black sand from the Manaccan valley in Cornwall in 1791; Martin Klaproth independently discovered it in 1795 and named it after the Titans.

Which element is the most diamagnetic of all?

Bismuth is the most strongly diamagnetic of all the elements, which is why a small magnet can be floated between two bismuth plates; it is also among the most electrically resistive metals.

Which is the densest stable element, about twice as dense as lead?

Osmium, at about 22.6 g/cm³, is the densest stable element, nearly twice lead's 11.3; Smithson Tennant named it in 1803 from the Greek osme, 'smell', for its pungent volatile tetroxide.

Selenium's name comes from the Greek for which celestial body?

Berzelius named selenium in 1817 from the Greek selene, 'the Moon', to pair it with the similar element tellurium, whose name comes from the Latin tellus, 'the Earth'.

Vanadium is named after Vanadís, a goddess of which mythology?

Vanadís is a byname of the Norse goddess Freyja; Nils Sefström chose it in 1830 for the beautifully coloured compounds the element forms.

Cadmium was discovered in 1817 as an impurity in which compound sold in German pharmacies?

Friedrich Stromeyer found that one supplier was selling zinc carbonate instead of zinc oxide.

Sulfuric acid was known to medieval alchemists by what name?

Oil of vitriol was the alchemists' name for sulfuric acid, H₂SO₄, made by roasting 'vitriols' such as green vitriol (iron sulfate); aqua fortis was nitric acid and spirit of salt hydrochloric.

Which chemist first isolated caffeine in 1819, calling it 'Kaffebase'?

Friedlieb Ferdinand Runge isolated caffeine in 1819 after Goethe handed him a box of coffee beans and suggested he analyse them; Runge later identified aniline and quinoline in coal tar.

Salicin, the precursor to aspirin, comes from the bark of which tree?

Salicin comes from willow bark, Salix in Latin, which gave the compound its name; the body turns it into salicylic acid, and Charles Gerhardt first made acetylsalicylic acid in 1853.

Kevlar, invented by Stephanie Kwolek in 1965, is how many times stronger than steel by weight?

DuPont's figure is that Kevlar is five times stronger than steel on an equal-weight basis; Stephanie Kwolek's para-aramid fibre first went into racing tyres in the early 1970s, before bulletproof vests.

Bakelite, the first fully synthetic plastic, was developed by Leo Baekeland in which year?

Leo Baekeland made the first phenol–formaldehyde resin in his Yonkers, New York laboratory in 1907 and filed his 'heat and pressure' patent that July; it was granted in December 1909.

Which Italian chemist first synthesised nitroglycerin in the 1840s?

Ascanio Sobrero made nitroglycerin in Turin by nitrating glycerol and warned it was too dangerous to use; Alfred Nobel tamed it as dynamite in 1867, and it later became a heart medicine.

TNT, first synthesised in 1863, was originally used as what?

Julius Wilbrand made TNT in 1863 and it was sold as a yellow dye; its explosive potential went unrecognised until the 1890s because it is so insensitive and hard to detonate.

In gunpowder, which ingredient acts as the oxidiser?

Sulfur and charcoal are the fuels; saltpetre is potassium nitrate.

The pH scale was introduced in 1909 by Søren Sørensen at which brewery's laboratory?

Søren Sørensen ran the chemistry department of the Carlsberg Laboratory in Copenhagen, where he introduced the pH scale in 1909 while studying enzyme activity for brewing; he never explained his choice of the letter p.

Which physicist defined entropy in 1865?

Rudolf Clausius coined the word entropy in 1865, from the Greek for 'transformation', defining its change as heat transferred divided by absolute temperature (dS = δQ/T), and declared that the entropy of the universe tends to a maximum.

Which chemist coined the terms 'pipette' and 'burette' in an 1824 paper?

Joseph Louis Gay-Lussac introduced the words pipette and burette in an 1824 paper on volumetric analysis; François Descroizilles had built the first burette-like device in 1791 for titrating bleach.

Graphene was first isolated in 2004 at which university, using adhesive tape and graphite?

Andre Geim and Konstantin Novoselov peeled single layers from graphite with Scotch tape at the University of Manchester in 2004, and shared the 2010 Nobel Prize in Physics for it.

Buckminsterfullerene, discovered in 1985, contains how many carbon atoms?

Buckminsterfullerene, C₆₀, has 60 carbon atoms at the vertices of a truncated icosahedron, the 12-pentagon, 20-hexagon pattern of a football; Kroto, Curl and Smalley found it in 1985.

Stainless steel resists rust thanks to a minimum of about 10.5% of which element?

The chromium forms a self-healing passive film when exposed to oxygen.

Galvanisation protects steel with a coating of which metal?

Zinc corrodes in place of the steel even where the coating is scratched, because it gives up electrons more readily; tin, by contrast, only protects while the coat is intact.

Lithium-ion batteries were first sold commercially in which year?

Sony put the first commercial lithium-ion battery on sale in 1991, built on Goodenough's cobalt-oxide cathode and Yoshino's carbon anode; Goodenough, Whittingham and Yoshino shared the 2019 Nobel Prize in Chemistry.

Radiocarbon dating was developed in the late 1940s by whom?

Carbon-14's half-life is about 5,730 years; Libby won the 1960 Nobel Prize in Chemistry.

Which two chemists proved that nuclear fission had occurred, in December 1938?

Otto Hahn and Fritz Strassmann found barium where none should be on 19 December 1938; Meitner and her nephew Frisch explained fission in January, and Hahn alone got the Nobel.

Which chemist developed leaded petrol and the first CFCs, and died strangled by his own bed device?

Thomas Midgley Jr. added tetraethyl lead to petrol in 1921 and devised Freon in 1928; in 1944, paralysed by polio, he was strangled by the rope-and-pulley system he had built to lift himself from bed.

Ahmed Zewail, the 1999 Nobel laureate in Chemistry, is known as the father of what field?

Ahmed Zewail founded femtochemistry, using laser pulses lasting femtoseconds (10⁻¹⁵ s) to film chemical bonds breaking and forming; he was the first Egyptian and Arab to win a scientific Nobel Prize.

Frances Arnold won the 2018 Nobel Prize in Chemistry for pioneering what technique for enzymes?

Directed evolution mimics natural selection in the lab: Frances Arnold mutated enzyme genes at random and screened for improved variants over repeated rounds, a method she first demonstrated in 1993.

Dan Shechtman won the 2011 Nobel Prize for discovering which ordered but non-periodic structures?

Quasicrystals are ordered but never repeat; Dan Shechtman saw the 'forbidden' ten-fold diffraction pattern of an icosahedral aluminium–manganese alloy on 8 April 1982 at the US National Bureau of Standards.

Percy Julian's synthesis work laid the foundation for the industrial production of which drug?

Percy Julian's 1949 route to cortexolone (Compound S) from soybean sterols made cortisone cheap enough for mass production; he had earlier been the first to synthesise physostigmine, in 1935.

Which chemist first proposed the idea behind phlogiston, in the 1660s?

Johann Joachim Becher's Physica subterranea described a 'fatty earth', terra pinguis, released in burning; Georg Stahl renamed it phlogiston around 1697, and Lavoisier's oxygen experiments overturned the theory in the 1770s and 1780s.

Helium was first detected in 1868 as a yellow spectral line in the Sun during what event?

Jules Janssen saw the 587.49 nm yellow line in the Sun's chromosphere during the total solar eclipse of 18 August 1868 at Guntur, India; Lockyer named the element helium, and Ramsay isolated it on Earth in 1895.

Roy Plunkett accidentally discovered PTFE, better known as Teflon, in 1938 while trying to make what?

Roy Plunkett was trying to make a new CFC refrigerant for DuPont when his tetrafluoroethylene gas stopped flowing from its pressure bottle before it emptied; inside was a waxy white polymer, PTFE.

Which mineral, a uraninite variety, did William Ramsay treat with acids to first isolate helium on Earth in 1895?

Ramsay treated cleveite with sulfuric acid looking for argon; after scrubbing nitrogen and oxygen from the liberated gas, its yellow line matched the Sun's D3 line. Hillebrand had obtained the same gas from uraninite in 1889 without identifying it.