Elements

A powdered form of this element is extracted via the Wohler process. This element's oxide is usually extracted from bauxite via the Bayer process, and occurs naturally as corundum. Industrially, the Hall-Heroult process produces this most abundant metal in the Earth's crust. For 10 points, name this element with atomic number thirteen that is used to make soda cans.

aluminum [or aluminium; or Al]

A compound with this anion is produced in a process whose first step uses a solution of ammonia and salt. This is the anion in the unstable mineral vaterite. This is the anion produced in the Leblanc and Solvay processes. This anion is formed along with a proton in a reaction catalyzed by a zinc-containing (*) anhydrase enzyme. Like chromates, hydroxides, phosphates, and sulfides, most compounds of this anion are insoluble. This anion is formed in ocean acidification, and a form of this anion is used in blood as a buffer. Adding acid to minerals containing this ion releases carbon dioxide. For 10 points, name this anion found in limestone, with formula "C-O-3 2-minus."

bicarbonate ion [or H-C-O-3 2-minus before mentioned]

An increase in this element's concentration in the Earth's past led to a sharp decrease in the concentration of nickel. Banded iron formations arose during the "Crisis" caused by this element, which led to the Huronian ice age and a possible Snowball Earth. When nitrates or phosphates enter water, this element's concentration decreases due to eutrophication. Radical chlorine atoms can abstract an atom of this element in the stratosphere, which limits the ability to absorb UV-B light. A mass extinction of anaerobes occurred when this element was first produced by photosynthetic cyanobacteria 2.4 billion years ago. For 10 points, name this element which makes up ozone.

oxygen [or O2]

HIF [hiff] transcription factors are activated by low concentrations of this element. The Warburg [VAR-burg] effect explains how low concentrations of it make tumor cells acidic. VEGF [vedge-F], secreted by tumor cells when this element is sparse, stimulates vasculo-genesis. Low concentrations of this element stimulate the reduction of (*) pyruvate, rather than the formation of oxaloacetate. This element is "evolved" during the light-dependent reactions. It is the final acceptor in the electron transport chain. Lack of this element favors formation of lactate in anaerobic fermentation. For 10 points, name this element required for cellular respiration, which is absorbed in the lungs.

oxygen [or O]

These entities are present in Hoogsten base pairing, and they are strongest when symmetric. These entities are considered electrostatic attractive forces, and one form of these is present in borane-ammonia complexes. They allow for the bonding of nucleotides in adenine and thymine, in addition to other nucleotides in DNA. These types of bonds occur between a highly electronegative element such as nitrogen, oxygen, or fluorine with a certain element. For 10 points, name these strongest intermolecular forces in covalent molecules which are responsible for surface tension and many of the other properties of water.

Hydrogen Bonds [accept Hydrogen after "bonds" is mentioned]

This element forms a red solution when it complexes with thiocyanate, and although it is not aluminum, a chloride of this element catalyzes a Friedel-Crafts alkylation. The oxide of this element is used industrially to produce ammonia in the Haber-Bosch process, and this element exists in a solid solution with carbon in its gamma variety austenite. This element is derived from the ore hematite, and its brass-colored pyrite is commonly known as "fool's gold". For 10 points, name this transition metal with chemical symbol Fe.

Iron

In order to complement the lunar crater naming system, all of the craters on this planet are named after nonscientific authors, composers, or artists. This planet has a 2:3 rotation to revolution ratio, meaning that its day is longer than its year. It is scheduled to be visited in 2020 by a joint European/Japanese mission named BepiColombo, while a hilly region known as the "Weird Terrain" is located antipodal to its Caloris Basin. The main goal of NASA's MESSENGER mission is to study this planet from orbit and to continue Mariner 10's mapping of its surface. For 10 points, identify this planet named for the Roman messenger god, the closest to the Sun.

Mercury

In perturbation theory, transition probability is related to a matrix squared times the density of final states by this man's "Golden Rule"; at absolute zero, his namesake "level" is equal to chemical potential. His namesake "paradox" states that in such a large universe, humans should have contacted [*] more aliens. With Dirac, he names a set of statistics for identical particles that obey the Pauli Exclusion Principle and have half-integer spin, and his namesake "lab" is an underground particle accelerator near Chicago. For 10 points, name this Italian-born nuclear physicist.

Enrico Fermi [accept Fermi's Golden Rule until 'this man's "Golden Rule"' is read] [MJ]

When sandwiched between lithium and a hydride group, this element is part of a powerful reducing agent. Ziegler-Natta catalysts typically consist of a mixture of titanium compounds and compounds of this element. It was first isolated by Hans Christian (*) Oersted, and commercial production of this element uses the Bayer process followed by the Hall-Heroult process to refine this element's principle ore, bauxite. For 10 points, name this most abundant metal in the earth's crust with atomic number 13 and symbol Al.

aluminum [or aluminium; or Al before mention]

12. The main source of this element in ore is composed of the minerals gibbsite, boehmite, and diaspore. It's not sodium or calcium, but this element is a cation in the minerals that make up the continuous branch of Bowen's reaction series. The natural pH indicator Hydrangea macrophylla changes color due to the presence of this element in the soil. This element is the cation in a mineral that becomes red due to the presence of chromium and measures a (*) 9 on the Mohs scale of mineral hardness. This element is extracted in the Bayer process and refined in the Hall-Héroult process. For 10 points, name this element found in corundum and bauxite with chemical symbol Al.

aluminum [prompt on "Al"]

12. The ATRAP project collected one type of this substance from radioactive sodium-22 in a Penning trap. The existence of another type of this substance was proposed by Dirac to explain quantum states with negative energies and was first observed by Carl Anderson. Because the Sakharov conditions were satisfied, CP-symmetry violation explains why there is less of this substance produced than its (*) counterpart. This substance produces high-energy gamma rays when it comes into contact with normal particles, which have the same mass but opposite charge as particles of this type. The positron is an example of, for ten points, what type of material which rapidly annihilates with matter?

antimatter (accept antiparticles; prompt on positrons and antihydrogen and other specific antiparticles)

Water gas is formed by passing steam over this element. This element forms the anode in the Hall-Heroult process. Ionic salts of it with silicon and boron are two of the hardest known compounds. The "activated" form of this element is used to purify water. This element is produced when sulfuric acid dehydrates glucose. Andre Geim [GYME] used Scotch tape to isolate a (*) 2D form of this element. This element forms a 60-atom cage with pentagonal and hexagonal faces that was named for architect R. Buckminster Fuller. An isotope of this element has a half-life of 5760 years. For 10 points, name this element whose allotropes include graphite and diamond.

carbon [or C]

. This molecule has an anti-symmetric stretching mode at 2349 inverse centimeters. A ruthenium carbonyl catalyst can be used to produce alcohols from olefins, hydrogen gas, and this compound. A phosphine complex of platinum catalyzes the conversion of hydrogen gas and this compound into formic acid. A supercritical fluid of this molecule is used in (*) decaffeination reactions. In the water-gas shift equilibrium, water and carbon monoxide are converted to hydrogen gas and this compound. It's produced alongside water in combustion reactions and constitutes dry ice. For 10 points, name this compound that has formula CO2.

carbon dioxide [accept "CO2" until read]

2. In one process, an unstable intermediate formed by adding three molecules of this compound breaks down into 3-phosphoglycerate, and that process is sometimes preceded by one in which this compound is added to form oxaloacetate and malate. An abnormally high amount of this substance in the blood is called hypercapnia and can lead to acidosis, as it forms an acid that is part of the (*) bicarbonate buffering mechanism. Yeast fermentation results in ethanol and this compound, which RuBisCO uses as a source of carbon atoms in the Calvin cycle. For ten points, name this gas that is used in photosynthesis and produced by respiration, whose chemical formula is CO2.

carbon dioxide [accept CO2 before mentioned]

In 2013, bismuth was used by Joel Rosenthal as a catalyst to create this compound. This compound is combined with water vapor in the water-gas shift reaction, and this is mixed with hydrogen to make synthetic fuel in the Fischer-Tropsch [tropsch] process. This compound combines with hemoglobin to create carboxyhemoglobin [kahr-BOK-see-hee-moe-gloe-bin], which causes oxygen deprivation. Name this compound that can be created by incomplete combustion so that there is not enough oxygen to create carbon dioxide.

carbon monoxide (prompt on "CO")

This compound is formed with hydrogen in steam reforming. Heme breakdown produces this compound. It inserts into alkenes to form aldehydes and inserts into methanol to form acetic acid. Addition of chlorine to this gas makes phosgene. This neutral compound has a triple bond, one atom with a positive charge, and one atom with a negative charge. A catalytic (*) converter oxidizes both hydrocarbons and this compound to CO2. It competitively inhibits binding to hemoglobin. It and water are formed in incomplete combustion reactions. For 10 points, name this poisonous gas which displaces oxygen in the body, which has formula CO.

carbon monoxide [or CO until it is read]

16. Chromium and ferric oxides are used in a flame fusion process to create one form of this this mineral in a technique named after Verneuil. Rutile silk cause a notable asterism in one form of it, and Gaudin's synthetic creation of it was the first for any gemstone. An orange form of this substance is known as padparadscha, and it is comprised of (*) aluminum oxide. This gemstone can get a red color due to chromium impurities, and its forms include emery, sapphire, and ruby. For ten points, identify this mineral which has a hardness of 9 on the Mohs scale.

corundum (accept aluminum oxide or Al2O3 before mention; accept ruby until "padparadscha")

Now considered the first person involved in this event, he described the combustion of saltpeter and manganese dioxide in his work A Chemical Treatise of Air and Fire. In addition to Carl Wilhelm Scheele another person involved in this event suggested using soda water, a process he initially described, as a cure for scurvy, and as a result of this event the phlogiston theory was overturned. For 10 points, name this event once credited to Joseph Priestly involving an element named by Lavoisier.

discovery of oxygen [accept clear-knowledge equivalents]

In 1920 Fritz Haber began a secret project to extract this element from seawater, after learning of Arrhenius's calculation that there must be eight million tons of it in the oceans. The pure form of this element is the most ductile and most malleable metal. Like platinum, it is most commonly dissolved using aqua regia (AH-kwuh REE-jee-uh). The amount of this metal in an alloy is expressed using units of karats. For 10 points, name this metal, into which alchemists attempted to convert lead.

gold [or Au]

This number gives the ratio of the side lengths of Penrose tile kites and darts. The Fibonacci [fih-boe-NAH-chee] sequence can be expressed using powers of this number and its reciprocal, and the limiting ratio of successive terms of the Fibonacci sequence equals this number. Removing a square sharing a side with a rectangle whose side lengths are in this ratio leaves another rectangle whose side lengths are in this ratio. Name this solution of x^2-x-1=0, an irrational number that approximately equals 1.618.

golden ratio (or golden mean or golden section or golden cut or mean of Phidias, accept divine in place of golden, prompt on "phi")

3. This value is the smallest quadratic irrational Pisot number. The edges of Kepler triangles increase in length by a geometric progression based on this number. This number can be expressed as a continued fraction consisting only of (*) ones. It can be found by solving the quadratic equation x-squared minus x minus one, and it is equal to one plus the square root of five all divided by two. The ratio of successive terms of the Fibonacci sequence approaches this value. For 10 points, name this number, symbolized phi, which often appears in nature and art, equal to about 1.618.

golden ratio [accept mean, number, or proportion instead of ratio; accept divine instead of golden, accept "phi" before mentioned

This constant is the length of a diagonal of a regular pentagon with side length 1, and a similarly named constant is equal to 1 plus the square root of 2. That constant is the limiting ratio of consecutive Pell numbers, while this constant is equal to the limiting ratio of consecutive (*) Fibonacci numbers. This constant can be expressed as an infinite square root with only 1's, and its continued fraction also consists of only 1's. This is the only positive number which is equal to the sum of 1 and its reciprocal, and the square of this number is equal to this number plus one. For ten points, name this constant which is frequently used in architecture and art, equal to 1 plus the square root of 5 over 2, or 1.618.

golden ratio [accept phi, accept 1 plus the square root of 5 over 2 before mention]

An allotrope of this element, Austenite, has vanadium or molybdenum stuck in its interstitial spaces to prevent corrosion in the new substance. Mossbauer spectroscopy is often used on this substance to assess bonding properties. This substance is used to produce ammonia or fuel in the (*) Haber-Bosch process. This element, when treated with acids made from halogens, produces ferrous and ferric halides. This metal has a "wrought" and "pig" type, and when it oxidizes, it forms rust. For ten points, name this transition metal with periodic number twenty-six and symbol Fe.

iron [accept Fe until mentioned]

This element sometimes exists in a gamma phase allotrope known as austenite. The pigment Prussian blue ideallycontains seven ions of this element complexed with eighteen cyanide ions. The mineral magnetite is an oxide of thiselement, and impure forms of this element undergo the Bessemer process to form an alloy of this metal and carbon.The mineral siderite is this element's carbonate, and a main source of this metal for its large-scale production comesfrom hematite. In humans, atoms of this element complex with the proteins myoglobin and hemoglobin. For 10points, name this element, a metal that forms steel with carbon and whose other oxide is rust.

iron [or Fe; accept ferrum]

One example of these compounds is produced by the oxidation of 2-butanol [BYOO-tah-nol], and a common test for these substances looks for the creation of iodoform [ie-oe-doe-FORM]. When humans produce too much of these chemicals because of too much fatty acid breakdown, their blood turns acidic, which is a diabetes symptom. The simplest example of this, used as nail polish remover, is acetone [A-suh-tone]. Name these carbonyls [KAHR-buh-nils] that are not aldehydes [AL-duh-hides] because the central carbon is bonded to two other carbons.

ketones (prompt on "carbonyl")

The Castner-Kellner Process produces a mixture with this substance and sodium while producing chlorine. In the patio process, this element is used to extract silver from ore. The most common source ore for refining this substance is the red sulfide mineral cinnabar. The chloride of this element is a common component of reference electrodes, known as (*) calomel. This element cannot form a monocation with a charge of 1+, and its alloys are known as amalgams. This transition metal's sulfide is cinnabar it is commonly used in thermometers. For ten points, identify this element, a liquid at room temperature, with symbol Hg.

mercury (accept Hg before mention)

The discovery of oxygen by Carl Scheele [SHAY-luh] and Joseph Priestley was accomplished by heating the oxide of this element. This compound was used with salt and copper sulfate to extract silver in the patio process. This is combined with silver, tin, and copper to make dental fillings known as amalgams, though its use is controversial because of its high toxicity. Similar concerns have decreased its use in vaccines and thermometers. Name this element formerly known as quicksilver, a metal that is liquid at room temperature.

mercury (prompt on "Hg")

The Franck-Hertz experiment used a tube filled with this element in a gaseous state, and various isotopes of this element were used to change in the critical temperature of superconductors due to the isotope effect. Found together with chlorine in calomel and sulfur in vermilion, it can be obtained from cinnabar, and forms alloys with other metals called amalgams. For 10 points, name this only element this is liquid at room temperatures, whose symbol is Hg.

mercury [accept Hg before it is read]

Most UV fluorescent lamps pass a current through this element. This element's plus-one oxidation state is dimeric and divalent. It forms a convex meniscus in a glass tube because it preferentially exhibits adhesion, not cohesion. This element dissolves gold to form an amalgam. 760 millimeters of this element is equivalent to one atmosphere of pressure, as it is commonly used in manometers. It is bonded to sulfur in a compound used as a preservative in vaccines, and foolishly blamed for autism, thiomersal. Like bromine, it is a liquid at room temperature. For 10 points, name this metal with atomic number 80 and symbol Hg.

mercury [or Hg before mention]

18. This element is bonded to four iodine atoms in Nessler's reagent, which it can precipitate out of when reacted with ammonia. This metal is found in the red pigment vermilion, since it is bonded to sulfur in cinnabar. Alloys of this metal used for dental fillings are called (*) amalgams. Measuring the height of this element in a column can determine pressure, with 760 millimeters corresponding to 1 atmosphere, and this element is also present in some thermometers. For ten points, identify this toxic metal that is liquid at room temperature with chemical symbol Hg.

mercury [or Hg early]

This element binds to four atoms of iodine to form Nessler's reagent, and was used to minimize friction in the Michelson-Morley experiment. Along with zinc, this metal is used as a reducing agent in the Clemmensen reduction. When bound to acetate, it can be used to transform an alkene into an alcohol. This metal, which is found in its (*) +2 state in the mineral cinnabar, forms alloys called amalgams. Despite its toxicity, it was used during the Renaissance as a treatment for syphilis, and it has also been used to preserve vaccines and fill glass thermometers. For 10 points, identify this element with symbol Hg.

mercury [prompt on "Hg" before read]

A nitrate of this element is used to create picric [PIK-rik] acid in the WolffensteinÂ\[Dash]BÃ\[Paragraph]ters reaction, and the previous name used for thiols ["THIGH"-awlz] came about because of their ability to bond with this element. This is the cause of Minamata disease, and the use of this element to make a vaccine preservative called Thiomersal ["thigh"-o-MER-sul] is now in decline because of rumored health effects. Because this element has a high boiling point and a high coefficient of expansion in addition to being a dense liquid, it has traditionally been used in barometers and thermometers. Name this element formerly known as quicksilver whose chemical symbol is Hg.

mercury [prompt on Hg]

7. The amount of this element in a substance can be determined with the Dumas and Kjeldahl methods. A process that combines this element with hydrogen typically uses a porous iron catalyst prepared by reducing magnetite. Four atoms of this element are bonded to the iron in a heme group, and it is bonded with two hydrogen atoms in an (*) amine group. Legumes engage in a symbiotic relationship with Rhyzobium bacteria because of their ability to "fix" this element into a more usable form. Its triply-bonded diatomic molecule is the most common in Earth's atmosphere. For ten points, identify this element found in fertilizers and ammonia, with symbol N.

nitrogen

A polyatomic ion with negative one charge consists of three atoms of this element and is called azide. Two atoms of this element and four atoms of hydrogen form a compound used in rocket fuel, called hydrazine. Negative 196 degrees Celsius is the boiling point for the compound that the natural elemental form of this element is found in. This diatomic element contains a triple bond and is the most abundant gas in the atmosphere. For 10 points, identify this element with atomic number 7 and symbol N.

nitrogen [or N before it is read]

One important metabolic pathway named for a compound containing this element generates ornithine and its namesake substance, urea. Pyrimidine and purine bases, such as adenine and thymine, are often given a name that reflects their containing this element. Bacteria fix this element by forming ammonia. For 10 points, name this element found in the amino group of amino acids, whose diatomic form is an inert gas.

nitrogen [or N]

This element is single-bonded to itself in hydrazine ("HIGH"-druh-zeen) and triple-bonded to carbon in cyanide. This element forms in the second of three steps of a cycle of stellar fusion reactions, and the oxide that this element forms when it takes a plus one charge is known as laughing gas. This element's diatomic form contains a triple bond. For 10 points, name this element whose diatomic form is the gas most prevalent in the earth's atmosphere.

nitrogen [or N]

Organisms that both perform this process and respire aerobically make use of leghemoglobin. This process is performed by the filamentous actinomycetes, which are symbiotic with mountain lilacs, and by (*) Rhizobium, which infect legumes to form root nodules. In this process, three successive pairs of hydrogen atoms are added to the namesake gas to form two molecules of ammonia. For 10 points, name this process by which a common, inert gas is converted into a biologically useful form.

nitrogen fixation

This is the largest homonuclear diatomic molecule with a pi-u molecular orbital at a lower energy than a sigma-g orbital. Along with water, carbon dioxide, and sulfur dioxide, it has a zero enthalpy of combustion. Old airbags produced this compound from sodium azide. It is isoelectronic to carbon monoxide. An iron catalyst is used to break down this compound at very high pressures in the Haber process because it is so unreactive. In nature, the conversion of it to ammonia is called "fixation." This compound makes up about 80% of the atmosphere. For 10 points, name this diatomic gas consisting of element number 7.

nitrogen gas [or N2]

One atom of this element is found in a prototypic furan and an atom of this element forms the bridge in an ether. The liquid form of one of its allotropes is paramagnetic. Reactive species of this element are potent free radicals. It is found with silicon in quartz. Another allotrope of this element absorbs UV radiation. It has atomic weight 16. Rust is a combination of iron and this. For 10 points, name this element that along with hydrogen is found in water.

oxygen

The solid red epsilon phase of this material has been shown to be a crystal of eight-atom molecules, and its singlet state has been observed in reactions with enzymes such as chloroperoxidase. Its singlet state can also mediate Diels-Alder and other -ene reactions, and this element undergoes a cycle with fluorine in certain massive stars. A lack of nickel or tectonic event are two theories for this element's namesake "catastrophe," or its precipitous increase in the atmosphere millions of years after the development of photosynthetic plants. For 10 points, this is what element of atomic weight 16, symbolized O?

oxygen

Thomas Kuhn's The Structure of Scientific Revolutions uses the question of when this element can be said to have been "discovered" to illustrate the concept of the accumulation of anomalies. One person who discovered this element, Carl Wilhelm Scheele, presumed that it could leech phlogiston out of a substance. Its name is Greek for "acid-former," and was given by Antoine Lavoisier. It was called "dephlogisticated air" by its third discoverer, Joseph Priestley. For 10 points, identify this element whose reactions with other substances were discovered to be the source of combustion.

oxygen

The Dole Effect involves the occurrence of this element, which is tested for in the Winkler test. James Dewar was the first to produce the liquid form of this element. When four of this element bonds together, it is called (*) "red," and this gas is the only diatomic one to exhibit its own magnetic moment. This third most abundant element in the universe is present in ozone. For 10 points, name this chemical element directly above sulfur on the periodic table, with a chemical symbol O.

oxygen [or O until mentioned]

Molecular orbital theory explains how the naturally occurring form of this element contains a double bond and is paramagnetic. This element was named dephlogisticated air when it was discovered by Joseph Priestley. An ether contains an atom of this element bonded to two alkyl groups. This element has the second highest electronegativity behind fluorine and reacts with a hydrocarbon in a typical combustion reaction. For 10 points, name this element, three of which are bonded to nitrogen in a nitrate ion.

oxygen [or O]

One atom of this element is found in the ring of a furan, and an atom of it is bound to two carbons in an epoxide. Reactive species of this element are due to unpaired electrons, making them radicals. Three atoms of this element make up a compound that absorbs (*) ultraviolet light in the atmosphere. Another form of this element is added to hydrocarbons in combustion reactions. For 10 points, name this element, number eight on the periodic table, which has a diatomic form that is required for aerobic cellular respiration.

oxygen [or O]

15. One way of calculating this quantity is through hydration of quinhydrone crystals, while another method pioneered by Sorenson uses a glass electrode. The value of this quantity at which a molecule carries no net charge is called the isoelectric point. Extreme values for this quantity can be computed using the Hammett function, and the (*) Henderson-Hasselbach equation relates the pKa to this property. Buffers resist the change in this quantity, which can be found by taking the negative logarithm of the hydrogen ion concentration. For ten points, identify this value, measured on a scale from 0-14, that expresses the acidity of a substance.

pH [accept power of hydrogen]

The hormone DHEA usually is connected to this ion, and a test measuring their level together is used to monitor adrenal gland function. Turpentine with this ion is generated by the Kraft process, which is sometimes named for this ion. This ion combines with magnesium to form Epsom salt, or with calcium to form gypsum. This ion combines with barium to form barite, and that same combination is used as an X-ray contrast agent. The most common iron supplements combine iron with this ion. Acids with this ion have become a problem in many lakes due to acid rain. Name this ion that combines with hydrogen to form sulfuric acid.

sulfate ion [accept SO2\[Minus] 4 or SO\[Minus]2 4 ; do not accept "sulfur" or "sulfite"]

This element extracted in the Frasch process is bonded to a hydrogen atom in a functional group once called a mercaptan. In nature, this element is most commonly found in an eight atom ring. This element is only found in the amino acids methionine and cysteine; in cysteine this element forms a type of bridge that links polypeptide chains. A compound containing this element bonded to two hydrogen atoms is notable for smelling like rotten eggs. For 10 points, name this element found below oxygen on the periodic table with chemical symbol S.

sulfur

It's not chlorine, but the chlorobi phylum of bacteria is named for this element. A motif containing four atoms of this non-metal are found in aconitase. Vitamin B1 is named for the fact that it contains nitrogen and this element. In bacteria, nitrogen fixation occurs in a catalyst containing molybdenum and a cluster of iron and this element. This element, found in high concentrations in keratin, forms a tertiary structure called its namesake bridge. This element is found between ethyl and methyl groups in the side chain of methionine, and it's also found in cysteine.Thiols contain this element. For 10 points, name this element with symbol S.

sulfur [or S before mention]

11. The genus Chromatium produces this element through oxidation, and the 3d orbitals in this element may contribute to catenation. This element's phase diagram has three triple points because it has two solid phases. Thiol groups of it function in biomolecular binding, such as in Coenzyme A, and this element also forms (*) crosslinking polymer chains during vulcanization. As a pure solid, this element forms a cyclic molecule with eight atoms, and one compound of this element and hydrogen smells like rotten eggs. For ten points, identify this yellow element with atomic number 16.

sulfur [or S]

This substance reacts with sodium chloride in the Mannheim process. This substance is created industrially through a process that employs vanadium (vuh-NAY-dee-um) oxide as a catalyst, the contact process. A certain trioxide combined with this compound is called oleum (OH-lee-um), and this compound's two hydrogen atoms per ionizable molecule makes it diprotic. For 10 points, name this strong acid found in car batteries with formula H-two S-O four.

sulfuric acid

This compound protonates nitric acid in the precursor step to the nitration of benzene. Sodium nitrate is reacted with this compound in one method of producing it which uses Glover towers known as the lead chamber process, while another method uses a vanadium oxide catalyst and is called the (*) contact process. The "fuming" form of this strong diprotic acid is known as oleum. This compound is reformed during the recharging of lead acid batteries, and the reaction of sulfur trioxide with water forms this compound, leading to its presence in the atmosphere of Venus and acid rain. For 10 points, name this acid with formula H2SO4.

sulfuric acid (accept H2SO4 before read; accept oil of vitriol)

In aromatic nitration, this compound deprotonates nitric acid in a classic electrophilic aromatic substitution reaction. This chemical is mass-produced with a process that uses a vanadium oxide catalyst, known as the contact process, which replaced the lead-chamber process. Oleum is called the [*] "fuming" type of this compound, and it is also known as "oil of vitriol." This compound is the acid in car batteries and it can be formed by adding sulfur trioxide to water, which occurs in the formation of acid rain. For 10 points, name this polyprotic strong acid with formula H2SO4.

sulfuric acid [accept "oil of vitriol" before mentioned; accept "H2SO4" before mentioned]

It was used in the first step of an obsolete process to transform sodium chloride to hydrogen, chlorine gas, and sodium carbonate, the Leblanc process. It was originally created with the use of Glover towers; though now produced by the [*] contact process, that method was known as the lead chamber process. Its pure form was formally known as oil of vitriol and, along with carbon dioxide and water, it is a main component of Venus' atmosphere. For 10 points, name this strong component of acid rain with formula H2SO4.

sulfuric acid [accept oil of vitriol early; accept H2SO4 early] [DB-N]

This compound is produced in a process that uses Glover towers to remove nitrogen oxide called the lead chamber process. This compound and a gas that generates it are found in a solution called oleum, which is formed with a vanadium pentoxide catalyst in the contact process. Also called "oil of vitriol," it is a major component of car batteries, Venus's atmosphere, and (*) acid rain. For 10 points, name this acid with formula H2SO4.

sulfuric acid [or oil of vitriol it is read; or H2SO4 before it is read]

The condensation of two molecules of this substance forms a biuret. In the human body, this molecule undergoesa cycle which reacts ornithine and carbamoyl phosphate to form citrulline. A BUN test is used to determine levels ofthis substance in the blood. The reaction of silver cyanate and ammonium chloride forms this product of the WÃ\[Paragraph]hlersynthesis. Ammonia and carbon dioxide are reacted to form this molecule in the Bosch-Meiser process. This organicmolecule consists of two amines connected by a central carbonyl group. For 10 points, name this product ofammonia processing in humans, a molecule for which urine is named.

urea [or CO(NH2)2; or carbamide; or carbonyl diamide; or carbonyldiamine; or diaminomethanal; or diaminomethanone]

20. This compound is produced with graphite in the Bosch reaction, and organic reactions in this medium have been demonstrated to be faster than in toluene and cyclohexane by Sharpless. This compound notably has a solid-liquid boundary with a (*) negative slope on a phase diagram, and the absolute temperature scale is based on this compound's triple point. It is produced with carbon dioxide during combustion, and this molecule has a bent geometry and two lone pairs, allowing the formation of multiple hydrogen bonds that reduce its density when solid. For ten points, identify this "universal solvent" with formula H2O.

water [accept H2O or dihydrogen monoxide early]

This molecule includes eight alpha-beta barrels, which are the main domains of its L polypeptide chains, and eight S chains. A magnesium ion binds to this molecule to activate it after a lysine residue is carbamylated, a process aided by its namesake activase. In the presence of oxygen, this molecule's main function produces phosphoglycolate and 3-phosphoglycerate, also called PGA, though it usually produces two PGA molecules. For 10 points, name this enzyme central to carbon fixation in the Calvin cycle and named for the reactions it catalyzes involving ribulose-1,5-bisphosphate.

RuBisCO [accept Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase]

Following this experiment, it was predicted that s is proportional to Q sub n squared and inversely proportional to the sine of phi over two to the fourth power. A later version of this experiment uses a conical glass tube sealed with mica containing "radium emanation" and bismuth-214 to emit particles at a (*) zinc sulfide screen. A scintillator was used to count the flashes of light created by the backward scattering of alpha particles in this experiment, which disproved J. J. Thomson's plum-pudding model of the atom. For 10 points, name this experiment, which led to the discovery of a positively charged nucleus.

Rutherford experiment (accept Gold Foil experiment or Geiger\[Dash]Marsden experiment)

This experiment is sometimes named for the two individuals who actually conducted it, Hans Geiger and Ernest Marsden. The set-up for this experiment included a circular sheet of zinc sulfide that lit up when contact was made by alpha particles. Those alpha particles sometimes were (*) reflected directly back to their source, a result described as "firing a fifteen-inch shell at a piece of tissue paper and hav[ing] it come back and hit you." For 10 points, name this experiment that discovered the positively charged nucleus.

Rutherford gold foil experiment [or Rutherford experiment; or Geiger-Marsden experiment

The Bernal-Fowler model uses the 4-site approach to model this substance. Certain Claisen rearrangements and Diels-Alder reactions exhibit reaction rate accelerations when carried out in emulsions of this substance, an effect studied by Sharpless. This substance is sometimes coordinated with crystals to help them (*) retain their crystalline properties, and the triple point of this substance defines the Kelvin scale. The heavy form of this substance contains higher deuterium content, and its solid state is less dense than its liquid state. For 10 points, name this universal solvent with formula H2O.

Water [accept H2O before mentioned, or dihydrogen monoxide]

In one process for producing this compound, nitric oxide and nitrogen dioxide act as catalysts in the Gay-Lussac tower and Glover tower, and in another, an oxidation takes place in the presence of silica beads and a vanadium (V) oxide catalyst, after which its namesake element's trioxide is reacted with water. This compound produced by the lead chamber process and the contact process acts as the electrolyte in lead-acid batteries, and it is the only diprotic strong acid. For 10 points, name this acid with formula H2SO4.

Sulfuric Acid [accept H2SO4 before it is read]

They're not aromatic, but halogenating these molecules with the aid of ultraviolet light proceeds through a free radical mechanism. The orientation of substituents in these molecules can be visualized, two carbons at a time, using Newman projections. The number of hydrogen atoms in the linear and branched forms of these molecules is two plus twice the number of (*) carbon atoms in the molecule, meaning their degree of unsaturation is zero. Cyclohexane and ethane are examples of, for ten points, what hydrocarbons which possess only carbon-carbon single bonds, unlike alkenes and alkynes?

alkanes [prompt on "hydrocarbons"]

These substances must obey the Hume-Rothery rules. These materials are strengthened during precipitation hardening, which prevents the movement of dislocations. They have both a solid\[CenterDot]us and a liquid\[CenterDot]us melting point, and also may have a eutectic point. These substances form when atoms substitute or interstice into a crystal lattice. Examples of these materials, like martensite or cementite, are (*) combinations of ferrite and austenite. When they contain mercury, they are called amalgams. They are equivalent to solid solutions. For 10 points, name these materials like pewter, steel, and bronze, which are mixtures of metals.

alloys [or solid solutions until it is read; prompt on solutions; ask for less specificity for answers of carbon steel]

Ionization smoke detectors rely on the ability of these entities to ionize oxygen and nitrogen. In a nuclear fusion chain reaction, three of these entities combine to form an atom of carbon in a process that forms a beryllium intermediate. Ernest Rutherford fired a beam of this particle to develop the idea of an extremely small, dense nucleus in his gold foil experiment. Because of this particle's composition, it is sometimes referred to as a helium nucleus, and uranium decays by emitting this particle. For 10 points, name this particle which contains two protons and two neutrons.

alpha particle (accept helium nucleus before mentioned)

These particles are emitted by radioactive static neutralizers as one of the final steps when producing paper. Already used to treat bone cancers, research is being done to attach bismuth and actinium [ak-TIH-nee-um] to sites near tumors to treat other cancers. These particles can cause lung cancer, most commonly doing so after the inhalation of radium. These were aimed at gold foil when the atomic nucleus was discovered by Ernest Rutherford. Name these particles equivalent to a helium nucleus.

alpha particles (or alpha radiation, prompt on "helium nucleus")

The enormous range of timescales on which these particles are produced are related to their energies by the Geiger\[Dash]Nuttall law. George Gamow modeled the production of these particles in terms of quantum tunneling out of a potential well. The production of these charged particles by (*) americium-241 underlies the operation of smoke detectors. The production of these particles decreases both the atomic number and mass number of their neutron-rich sources, and they have same constituents as a helium-4 nucleus. A sheet of paper can easily stop \[LongDash]for 10 points\[LongDash]what form of ionizing radiation, composed of two protons and two neutrons?

alpha particles [or alpha radiation; or helium-4 nucleus before mention; do not accept or prompt on "helium" or "helium atom"]

This element is alloyed with nickel in a hydrogenating catalyst named for Raney. This element's potassium sulfate is used as a fire retardant and as a flocculant in water purification. This element's trichloride is a strong Lewis acid, since this element is trivalent like its group-mate (*) boron. When smelting this metal, its oxide is dissolved in molten cryolite, after the Bayer process extracts its metal's oxide from bauxite. This metal is found in the plus-three oxidation state in corundum. For 10 points, name this lightweight metal produced in the Hall\[Dash]Héroult process, with symbol Al.

aluminum

17. Conway weighted squares on a grid with powers of this number to show that a half-plane of adjacently jumping checkers can never advance five rows over. This number's continued fraction consists entirely of ones, and it is equal to 2 times the cosine of pi-fifths. This is the ratio of the diagonal of a regular pentagon to the length of its side, and an isosceles triangle with base angle (*) 72 degrees has side-ratio equal to it. The ratio of successive terms in the Fibonacci sequence approaches this number, whose square is one larger than itself. For ten points, identify this constant symbolized by the Greek letter phi and equal to about 1.618, named for its aesthetically pleasing properties.

golden ratio/mean/section/proportion (or divine in place of golden, accept mean of Phidias, accept (1+\[Sqrt]5)/2 , accept phi before mentioned, prompt on decimal approximations which are the first few digits of 1.61803...)

The presence of this element's degenerate type leads to its namesake flash. This element with more than one valence electron was produced during the nucleosynthesis after the Big Bang. The CNO cycle is used to produce this element, which is consumed in red giants during the triple-alpha process. It was first discovered as a (*) yellow spectral line during a solar eclipse in 1868. This element has a 25% abundance in the universe, and its nucleus is equivalent to an alpha particle. Within most stars, it is created by the nuclear fusion of hydrogen atoms, which it has double the protons of. For 10 points, name this element, the lightest noble gas, with atomic symbol He.

helium (prompt on "He" before read)

An ion containing this element along with fluorine and oxygen has been predicted stable. In one experiment, the nuclei of this element were fired at a thin layer of gold atoms. Superfluidity has been observed in both its isotopes three and four. This element is the lightest with a full s subshell. Its nuclei are alpha particles. For 10 points, name this gas with atomic number two.

helium [or He]

Because of its zero-point energy, this element has no melting point. This element and nitrogen are the most common carrier solvents in semiconductor manufacturing and in gas chromatography. It has the highest first ionization energy. The plus-one cation of this element can be modelled by the Rydberg [RIDE-berg] equation. The liquid form of this element exhibits (*) superfluidity. This element was discovered as a yellow spectral line during a solar eclipse. In the gold foil experiment, Rutherford fired nuclei of this element, or alpha particles, at the foil. For 10 points, name this lightest noble gas, which has atomic number 2.

helium [or He]

This element is often used in mass spectrometers to detect leaks because it is a very minor constituent of air, it is safe, and it is easy to separate from other gases. Though not part of natural gas, this element is released during natural gas extraction, which is increasing the cost of cooling MRI scanners due to a shortage of this element. The fusion of three of its nuclei creates a carbon nucleus. The name of this element arose because it was first observed in the Sun's spectrum, and its nucleus is an alpha particle. Name this lightest noble gas, the second element on the periodic table.

helium [prompt on He]

This element is separated from sulfur in the Claus process. The molecular form of this element is added to pyridine [PEH-rih-deen] to cause several reactions leading to the formation of pentane, and the addition of this element changes an alkene into an alkane. Just outside the cores of Jupiter and Saturn, astronomers have found the metallic form of this element. The isotopes of this element are protium, deuterium, and tritium. Name this element, the first in the periodic table.

hydrogen (prompt on "H")

12. One type of this element was confined in a Penning trap as part of the ATHENA project. The ionization of an isotope of this element in fusors produces a pink glow. The Lyman-alpha forest arises due to the presence of this element. The transition between two hyperfine levels of this element produces the (*) 21 centimeter line. The lowest electron energy level in this element is -13.6 eV. Six atoms of this element produce a helium atom in the proton-proton chain reaction. The Bohr model most accurately describes this element. For 10 points, name this most abundant element in the universe that typically consists of one proton and one electron.

hydrogen [accept deuterium, prompt on "H"]

15. This element can be added to certain molecules with a palladium catalyst named after Lindlar. Standard reduction potentials are normalized to the reduction of this element at a platinum electrode. A type of molecular interaction named after this element results from the tendency of elements like (*) oxygen and fluorine to attract electrons away from this element and give it a partial positive charge. A molecule of methane contains one carbon atom and four atoms of this element. For 10 points, name this element which bonds with oxygen to form water.

hydrogen [or H]

Two atoms of this element are appended in the Birch Reduction. One isotope of this element replaces a lighter isotope in a chloroform derivative used as a solvent in NMR. That isotope was discovered by Harold Urey. A compound in which this element is combined with oxygen is broken down by the enzyme catalase (CAT-uh-"lace"). Isotopes of this element include deuterium (doo-TAIR-ee-um) and tritium. Two of this element fuse to create helium. For 10 points, name this lightest element.

hydrogen [or H]

This phenomenon is often wrongly believed to be the reason why DMSO can be needed during PCR, when in reality pi stacking is the cause. By connecting carbonyl groups to amino groups four residues away, it creates alpha helices. This interaction is responsible for causing hydrofluoric acid to (*) boil at a higher temperature than hydrochloric acid. Only two of these interactions occur between thymine and adenine, while three occur between guanine and cytosine, and these interactions are responsible for making ice float on water. For ten points, name this interaction that is responsible for the high specific heat of water, as well as its cohesive and adhesive nature.

hydrogen bonds