Uranium

context: Depleted uranium is also used as a shielding material in some containers used to store and transport radioactive materials. While the metal itself is radioactive, its high density makes it more effective than lead in halting radiation from strong sources such as radium. Other uses of depleted uranium include counterweights for aircraft control surfaces, as ballast for missile re-entry vehicles and as a shielding material. Due to its high density, this material is found in inertial guidance systems and in gyroscopic compasses. Depleted uranium is preferred over similarly dense metals due to its ability to be easily machined and cast as well as its relatively low cost. The main risk of exposure to depleted uranium is chemical poisoning by uranium oxide rather than radioactivity (uranium being only a weak alpha emitter).
qas: answers: text: Depleted
question: What kind of uranium is sometimes used to shield radioactive materials in containers?

answers: text: radium
question: What is a strong source of radiation that is blocked by depleted uranium?

answers: text: ballast
question: How is depleted uranium used in missile re-entry vehicles?

answers: text: high density
question: What trait causes depleted uranium to be used in gyroscopic compasses?

answers: text: weak
question: What type of alpha emitter is uranium?

context: The discovery and isolation of radium in uranium ore (pitchblende) by Marie Curie sparked the development of uranium mining to extract the radium, which was used to make glow-in-the-dark paints for clock and aircraft dials. This left a prodigious quantity of uranium as a waste product, since it takes three tonnes of uranium to extract one gram of radium. This waste product was diverted to the glazing industry, making uranium glazes very inexpensive and abundant. Besides the pottery glazes, uranium tile glazes accounted for the bulk of the use, including common bathroom and kitchen tiles which can be produced in green, yellow, mauve, black, blue, red and other colors.
qas: answers: text: pitchblende
question: What is another term for uranium ore?

answers: text: Marie Curie
question: Who isolated radium in uranium ore?

answers: text: glow-in-the-dark
question: In what types of paints was radium first used?

answers: text: clock and aircraft dials
question: What devices were painted with radium paint?

answers: text: mauve
question: Along with red, blue, black, yellow and green, what was a notable color of uranium tile glaze?

context: The X-10 Graphite Reactor at Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee, formerly known as the Clinton Pile and X-10 Pile, was the world's second artificial nuclear reactor (after Enrico Fermi's Chicago Pile) and was the first reactor designed and built for continuous operation. Argonne National Laboratory's Experimental Breeder Reactor I, located at the Atomic Energy Commission's National Reactor Testing Station near Arco, Idaho, became the first nuclear reactor to create electricity on 20 December 1951. Initially, four 150-watt light bulbs were lit by the reactor, but improvements eventually enabled it to power the whole facility (later, the town of Arco became the first in the world to have all its electricity come from nuclear power generated by BORAX-III, another reactor designed and operated by Argonne National Laboratory). The world's first commercial scale nuclear power station, Obninsk in the Soviet Union, began generation with its reactor AM-1 on 27 June 1954. Other early nuclear power plants were Calder Hall in England, which began generation on 17 October 1956, and the Shippingport Atomic Power Station in Pennsylvania, which began on 26 May 1958. Nuclear power was used for the first time for propulsion by a submarine, the USS Nautilus, in 1954.
qas: answers: text: Enrico Fermi's Chicago Pile
question: What was the world's first artificial nuclear reactor?

answers: text: Tennessee
question: In what state is the X-10 Graphite Reactor located?

answers: text: the Clinton Pile
question: Along with the X-10 Pile, what was the X-10 Graphite Reactor previously known as?

answers: text: Idaho
question: In what state is Argonne National Laboratory's Experimental Breeder Reactor I located?

answers: text: 20 December 1951
question: On what date did Breeder Reactor I first make electricity?

context: Uranium is a naturally occurring element that can be found in low levels within all rock, soil, and water. Uranium is the 51st element in order of abundance in the Earth's crust. Uranium is also the highest-numbered element to be found naturally in significant quantities on Earth and is almost always found combined with other elements. Along with all elements having atomic weights higher than that of iron, it is only naturally formed in supernovae. The decay of uranium, thorium, and potassium-40 in the Earth's mantle is thought to be the main source of heat that keeps the outer core liquid and drives mantle convection, which in turn drives plate tectonics.
qas: answers: text: 51st
question: Where does uranium rank among elements in terms of its abundance in the Earth's crust?

answers: text: in supernovae
question: Where is uranium naturally formed?

answers: text: thorium
question: Along with potassium-40 and uranium, the decay of what element is a primary heat source driving plate tectonics?

answers: text: liquid
question: In what state is the Earth's outer core?

context: Uranium-235 was the first isotope that was found to be fissile. Other naturally occurring isotopes are fissionable, but not fissile. On bombardment with slow neutrons, its uranium-235 isotope will most of the time divide into two smaller nuclei, releasing nuclear binding energy and more neutrons. If too many of these neutrons are absorbed by other uranium-235 nuclei, a nuclear chain reaction occurs that results in a burst of heat or (in special circumstances) an explosion. In a nuclear reactor, such a chain reaction is slowed and controlled by a neutron poison, absorbing some of the free neutrons. Such neutron absorbent materials are often part of reactor control rods (see nuclear reactor physics for a description of this process of reactor control).
qas: answers: text: 235
question: What isotope of uranium was the first to be found fissile?

answers: text: an explosion
question: When a nuclear chain reaction in uranium-235 doesn't result in a burst of heat, what does it result in?

answers: text: two
question: How many nuclei does uranium-235 usually divide into when bombarded with slow neutrons?

answers: text: neutron poison
question: What is used to slow a chain reaction in a nuclear reactor?

answers: text: free neutrons
question: What does a neutron poison absorb?

context: In nature, uranium(VI) forms highly soluble carbonate complexes at alkaline pH. This leads to an increase in mobility and availability of uranium to groundwater and soil from nuclear wastes which leads to health hazards. However, it is difficult to precipitate uranium as phosphate in the presence of excess carbonate at alkaline pH. A Sphingomonas sp. strain BSAR-1 has been found to express a high activity alkaline phosphatase (PhoK) that has been applied for bioprecipitation of uranium as uranyl phosphate species from alkaline solutions. The precipitation ability was enhanced by overexpressing PhoK protein in E. coli.
qas: answers: text: carbonate
question: What type of complexes does uranium(VI) form in nature?

answers: text: carbonate
question: The presence of what substance at alkaline pH makes it difficult to precipitate uranium as phosphate?

answers: text: Sphingomonas sp.
question: What is BSAR-1 a strain of?

context: It is estimated that 5.5 million tonnes of uranium exists in ore reserves that are economically viable at US$59 per lb of uranium, while 35 million tonnes are classed as mineral resources (reasonable prospects for eventual economic extraction). Prices went from about $10/lb in May 2003 to $138/lb in July 2007. This has caused a big increase in spending on exploration, with US$200 million being spent worldwide in 2005, a 54% increase on the previous year. This trend continued through 2006, when expenditure on exploration rocketed to over $774 million, an increase of over 250% compared to 2004. The OECD Nuclear Energy Agency said exploration figures for 2007 would likely match those for 2006.
qas: answers: text: 5.5
question: How much economically viable uranium is there in ore reserves, in millions of tonnes?

answers: text: 35
question: How many millions of tonnes are uranium are regarded as mineral resources?

answers: text: $10
question: What was the price of uranium per pound as of May 2003?

answers: text: US$200 million
question: In 2005, how much money was spent on uranium exploration?

answers: text: $774 million
question: How much money was spent to explore for uranium in 2006?

context: A team led by Enrico Fermi in 1934 observed that bombarding uranium with neutrons produces the emission of beta rays (electrons or positrons from the elements produced; see beta particle). The fission products were at first mistaken for new elements of atomic numbers 93 and 94, which the Dean of the Faculty of Rome, Orso Mario Corbino, christened ausonium and hesperium, respectively. The experiments leading to the discovery of uranium's ability to fission (break apart) into lighter elements and release binding energy were conducted by Otto Hahn and Fritz Strassmann in Hahn's laboratory in Berlin. Lise Meitner and her nephew, the physicist Otto Robert Frisch, published the physical explanation in February 1939 and named the process "nuclear fission". Soon after, Fermi hypothesized that the fission of uranium might release enough neutrons to sustain a fission reaction. Confirmation of this hypothesis came in 1939, and later work found that on average about 2.5 neutrons are released by each fission of the rare uranium isotope uranium-235. Further work found that the far more common uranium-238 isotope can be transmuted into plutonium, which, like uranium-235, is also fissile by thermal neutrons. These discoveries led numerous countries to begin working on the development of nuclear weapons and nuclear power.
qas: answers: text: 1934
question: When was it observed that bombarding uranium with neutrons results in beta ray emission?

answers: text: Enrico Fermi
question: Who led the team that discovered that bombarding uranium with neutrons created beta ray emissions?

answers: text: hesperium
question: What was the name given by Corbino to the incorrectly designated atomic number 94?

answers: text: Dean of the Faculty of Rome
question: What was the job title of Orso Mario Corbino?

answers: text: Lise Meitner
question: Who was the aunt of Otto Robert Frisch?

context: The interactions of carbonate anions with uranium(VI) cause the Pourbaix diagram to change greatly when the medium is changed from water to a carbonate containing solution. While the vast majority of carbonates are insoluble in water (students are often taught that all carbonates other than those of alkali metals are insoluble in water), uranium carbonates are often soluble in water. This is because a U(VI) cation is able to bind two terminal oxides and three or more carbonates to form anionic complexes.
qas: answers: text: carbonate containing solution
question: In what medium does the Pourbaix diagram change when carbonate anions interact with uranium(VI)?

answers: text: uranium
question: What notable carbonates are often water soluble?

answers: text: anionic complexes
question: What does a uranium(VI) cation form when it binds to two terminal oxides and three or more carbonates?

context: Uranium is more plentiful than antimony, tin, cadmium, mercury, or silver, and it is about as abundant as arsenic or molybdenum. Uranium is found in hundreds of minerals, including uraninite (the most common uranium ore), carnotite, autunite, uranophane, torbernite, and coffinite. Significant concentrations of uranium occur in some substances such as phosphate rock deposits, and minerals such as lignite, and monazite sands in uranium-rich ores (it is recovered commercially from sources with as little as 0.1% uranium).
qas: answers: text: molybdenum
question: Along with arsenic, what metal is roughly as abundant as uranium?

answers: text: antimony
question: Along with silver, mercury, tin and cadmium, what metal is uranium more plentiful than?

answers: text: uraninite
question: What is the most prevalent uranium ore?

answers: text: lignite
question: What mineral sometimes contains uranium?

answers: text: phosphate
question: What types of rocks sometimes contain uranium?

context: Natural uranium consists of three major isotopes: uranium-238 (99.28% natural abundance), uranium-235 (0.71%), and uranium-234 (0.0054%). All three are radioactive, emitting alpha particles, with the exception that all three of these isotopes have small probabilities of undergoing spontaneous fission, rather than alpha emission. There are also five other trace isotopes: uranium-239, which is formed when 238U undergoes spontaneous fission, releasing neutrons that are captured by another 238U atom; uranium-237, which is formed when 238U captures a neutron but emits two more, which then decays to neptunium-237; uranium-233, which is formed in the decay chain of that neptunium-237; and finally, uranium-236 and -240, which appear in the decay chain of primordial plutonium-244. It is also expected that thorium-232 should be able to undergo double beta decay, which would produce uranium-232, but this has not yet been observed experimentally.
qas: answers: text: uranium-234
question: What is the least prevalent major isotope of natural uranium?

answers: text: 0.71%
question: What is the natural abundance of uranium-235?

answers: text: uranium-239
question: What isotope of uranium is formed when 238U experiences spontaneous fission?

answers: text: uranium-233
question: When uranium isotope is formed from the decay of neptunium-237?

answers: text: thorium-232
question: What isotope is it theorized will form uranium-2343 after double beta decay?

context: An additional 4.6 billion tonnes of uranium are estimated to be in sea water (Japanese scientists in the 1980s showed that extraction of uranium from sea water using ion exchangers was technically feasible). There have been experiments to extract uranium from sea water, but the yield has been low due to the carbonate present in the water. In 2012, ORNL researchers announced the successful development of a new absorbent material dubbed HiCap which performs surface retention of solid or gas molecules, atoms or ions and also effectively removes toxic metals from water, according to results verified by researchers at Pacific Northwest National Laboratory.
qas: answers: text: 4.6 billion
question: About how many tonnes of uranium is theorized to be present in the sea?

answers: text: HiCap
question: What did ORNL call their material that performs surface retention on solid molecules?

answers: text: carbonate
question: The presence of what substance in sea water has resulted in low yields when attempting to extract uranium?

answers: text: Pacific Northwest National Laboratory
question: Where were ORNL's results verified?

answers: text: 2012
question: When was HiCap announced?

context: Many contemporary uses of uranium exploit its unique nuclear properties. Uranium-235 has the distinction of being the only naturally occurring fissile isotope. Uranium-238 is fissionable by fast neutrons, and is fertile, meaning it can be transmuted to fissile plutonium-239 in a nuclear reactor. Another fissile isotope, uranium-233, can be produced from natural thorium and is also important in nuclear technology. While uranium-238 has a small probability for spontaneous fission or even induced fission with fast neutrons, uranium-235 and to a lesser degree uranium-233 have a much higher fission cross-section for slow neutrons. In sufficient concentration, these isotopes maintain a sustained nuclear chain reaction. This generates the heat in nuclear power reactors, and produces the fissile material for nuclear weapons. Depleted uranium (238U) is used in kinetic energy penetrators and armor plating.
qas: answers: text: Uranium-235
question: What is the sole fissile isotope that occurs in nature?

answers: text: Uranium-238
question: What can be turned into plutonium-239 in a nuclear reactor?

answers: text: uranium-233
question: What uranium isotope is produced from thorium?

answers: text: uranium-233
question: Along with uranium-235, what isotope is noted for having a high fission cross-section for slow neutrons?

answers: text: Depleted uranium
question: What is 238U?

context: A person can be exposed to uranium (or its radioactive daughters, such as radon) by inhaling dust in air or by ingesting contaminated water and food. The amount of uranium in air is usually very small; however, people who work in factories that process phosphate fertilizers, live near government facilities that made or tested nuclear weapons, live or work near a modern battlefield where depleted uranium weapons have been used, or live or work near a coal-fired power plant, facilities that mine or process uranium ore, or enrich uranium for reactor fuel, may have increased exposure to uranium. Houses or structures that are over uranium deposits (either natural or man-made slag deposits) may have an increased incidence of exposure to radon gas. The Occupational Safety and Health Administration (OSHA) has set the permissible exposure limit for uranium exposure in the workplace as 0.25 mg/m3 over an 8-hour workday. The National Institute for Occupational Safety and Health (NIOSH) has set a recommended exposure limit (REL) of 0.2 mg/m3 over an 8-hour workday and a short-term limit of 0.6 mg/m3. At levels of 10 mg/m3, uranium is immediately dangerous to life and health.
qas: answers: text: Occupational Safety and Health Administration
question: What is OSHA?

answers: text: 0.25 mg/m3
question: What is the OSHA uranium exposure limit for an 8-hour workday?

answers: text: recommended exposure limit
question: What does REL stand for?

answers: text: 0.2 mg/m3
question: What is the NIOSH uranium exposure standard over an 8-hour workday?

answers: text: 10 mg/m3
question: At what level of exposure does uranium become imminently dangerous to health?

context: The most common forms of uranium oxide are triuranium octoxide (U
3O
8) and UO
2. Both oxide forms are solids that have low solubility in water and are relatively stable over a wide range of environmental conditions. Triuranium octoxide is (depending on conditions) the most stable compound of uranium and is the form most commonly found in nature. Uranium dioxide is the form in which uranium is most commonly used as a nuclear reactor fuel. At ambient temperatures, UO
2 will gradually convert to U
3O
8. Because of their stability, uranium oxides are generally considered the preferred chemical form for storage or disposal.
qas: answers: text: triuranium octoxide
question: Along with UO2, what is the commonest form of uranium oxide?

answers: text: Triuranium octoxide
question: What is the stablest uranium compound?

answers: text: Uranium dioxide
question: In what form is uranium most often used as fuel for nuclear reactors?

context: The use of uranium in its natural oxide form dates back to at least the year 79 CE, when it was used to add a yellow color to ceramic glazes. Yellow glass with 1% uranium oxide was found in a Roman villa on Cape Posillipo in the Bay of Naples, Italy, by R. T. Gunther of the University of Oxford in 1912. Starting in the late Middle Ages, pitchblende was extracted from the Habsburg silver mines in Joachimsthal, Bohemia (now Jáchymov in the Czech Republic), and was used as a coloring agent in the local glassmaking industry. In the early 19th century, the world's only known sources of uranium ore were these mines.
qas: answers: text: 79 CE
question: What was the earliest year in recorded history that uranium oxide was used?

answers: text: Italy
question: In what county was glass with uranium oxide content found?

answers: text: yellow
question: What color of ceramic glaze was extracted from uranium oxide?

answers: text: 1912
question: In what year was yellow uranium oxide glass discovered?

answers: text: the University of Oxford
question: What institution did R.T. Gunther belong to?

context: On 2 December 1942, as part of the Manhattan Project, another team led by Enrico Fermi was able to initiate the first artificial self-sustained nuclear chain reaction, Chicago Pile-1. Working in a lab below the stands of Stagg Field at the University of Chicago, the team created the conditions needed for such a reaction by piling together 400 short tons (360 metric tons) of graphite, 58 short tons (53 metric tons) of uranium oxide, and six short tons (5.5 metric tons) of uranium metal, a majority of which was supplied by Westinghouse Lamp Plant in a makeshift production process.
qas: answers: text: Chicago Pile-1
question: What was the first self-sustained nuclear chain reaction created by human beings called?

answers: text: 2 December 1942
question: On what date was the first self-sustained nuclear chain reaction created artificially?

answers: text: Manhattan
question: What project was Fermi working for?

answers: text: University of Chicago
question: On the campus of what educational institution was Chicago Pile-1 created?

answers: text: 53
question: How many metric tons of uranium oxide was used in Chicago Pile-1?

context: Uranium is used as a colorant in uranium glass producing orange-red to lemon yellow hues. It was also used for tinting and shading in early photography. The 1789 discovery of uranium in the mineral pitchblende is credited to Martin Heinrich Klaproth, who named the new element after the planet Uranus. Eugène-Melchior Péligot was the first person to isolate the metal and its radioactive properties were discovered in 1896 by Henri Becquerel. Research by Otto Hahn, Lise Meitner, Enrico Fermi and others, such as J. Robert Oppenheimer starting in 1934 led to its use as a fuel in the nuclear power industry and in Little Boy, the first nuclear weapon used in war. An ensuing arms race during the Cold War between the United States and the Soviet Union produced tens of thousands of nuclear weapons that used uranium metal and uranium-derived plutonium-239. The security of those weapons and their fissile material following the breakup of the Soviet Union in 1991 is an ongoing concern for public health and safety. See Nuclear proliferation.
qas: answers: text: orange-red
question: Along with lemon yellow, what color is produced in uranium glass?

answers: text: Martin Heinrich Klaproth
question: Who discovered uranium in pitchblende?

answers: text: Eugène-Melchior Péligot
question: Who was responsible for first isolating uranium?

answers: text: Henri Becquerel
question: Who discovered that uranium was radioactive?

answers: text: Little Boy
question: What was the first nuclear weapon used in a war called?

context: In nature, uranium is found as uranium-238 (99.2742%) and uranium-235 (0.7204%). Isotope separation concentrates (enriches) the fissionable uranium-235 for nuclear weapons and most nuclear power plants, except for gas cooled reactors and pressurised heavy water reactors. Most neutrons released by a fissioning atom of uranium-235 must impact other uranium-235 atoms to sustain the nuclear chain reaction. The concentration and amount of uranium-235 needed to achieve this is called a 'critical mass'.
qas: answers: text: 0.7204%
question: What percentage of uranium in nature is uranium-235?

answers: text: critical mass
question: What is the term for the amount of uranium-235 needed to sustain a nuclear chain reaction?

answers: text: uranium-238
question: What is the most prevalent natural isotope of uranium?

answers: text: 99.2742%
question: What percentage of natural uranium is isotope 238?

answers: text: pressurised heavy water
question: Along with gas cooled reactors, what type of reactor doesn't use uranium-235?

context: The major application of uranium in the military sector is in high-density penetrators. This ammunition consists of depleted uranium (DU) alloyed with 1–2% other elements, such as titanium or molybdenum. At high impact speed, the density, hardness, and pyrophoricity of the projectile enable the destruction of heavily armored targets. Tank armor and other removable vehicle armor can also be hardened with depleted uranium plates. The use of depleted uranium became politically and environmentally contentious after the use of such munitions by the US, UK and other countries during wars in the Persian Gulf and the Balkans raised questions concerning uranium compounds left in the soil (see Gulf War Syndrome).
qas: answers: text: high-density penetrators
question: What is uranium used for most often in the military?

answers: text: molybdenum
question: Along with titanium, what element often makes up the portion of high-density penetrators not made of depleted uranium?

answers: text: 1–2%
question: What percentage of high-density penetrators is not made up of depleted uranium?

answers: text: Persian Gulf
question: Along with the Balkans, in what geographical location did a war take place where the UK used depleted uranium munitions?

answers: text: Gulf War Syndrome
question: What illness is possibly tied to the use of depleted uranium munitions?

context: The discovery of the element is credited to the German chemist Martin Heinrich Klaproth. While he was working in his experimental laboratory in Berlin in 1789, Klaproth was able to precipitate a yellow compound (likely sodium diuranate) by dissolving pitchblende in nitric acid and neutralizing the solution with sodium hydroxide. Klaproth assumed the yellow substance was the oxide of a yet-undiscovered element and heated it with charcoal to obtain a black powder, which he thought was the newly discovered metal itself (in fact, that powder was an oxide of uranium). He named the newly discovered element after the planet Uranus, (named after the primordial Greek god of the sky), which had been discovered eight years earlier by William Herschel.
qas: answers: text: Martin Heinrich Klaproth
question: Who discovered uranium?

answers: text: 1789
question: In what year did the discovery of uranium occur?

answers: text: Berlin
question: In what city was uranium discovered?

answers: text: sodium diuranate
question: What did Klaproth probably create when he dissolved pitchblende in nitric acid?

answers: text: William Herschel
question: Who discovered the planet Uranus?

context: Uranium ore is mined in several ways: by open pit, underground, in-situ leaching, and borehole mining (see uranium mining). Low-grade uranium ore mined typically contains 0.01 to 0.25% uranium oxides. Extensive measures must be employed to extract the metal from its ore. High-grade ores found in Athabasca Basin deposits in Saskatchewan, Canada can contain up to 23% uranium oxides on average. Uranium ore is crushed and rendered into a fine powder and then leached with either an acid or alkali. The leachate is subjected to one of several sequences of precipitation, solvent extraction, and ion exchange. The resulting mixture, called yellowcake, contains at least 75% uranium oxides U3O8. Yellowcake is then calcined to remove impurities from the milling process before refining and conversion.
qas: answers: text: 0.01 to 0.25%
question: What percentage range of uranium oxide is usually contained in low-grade uranium ore?

answers: text: borehole
question: Along with underground, open pit and in-situ leaching, what sort of mining is used to mine uranium?

answers: text: Canada
question: In what country are high-grade uranium ores notably found?

answers: text: Saskatchewan
question: In what province of Canada is the Athabasca Basin?

answers: text: 23%
question: What is the average percentage of uranium oxide contained in the ores mined in the Athabasca Basin?

context: Two major types of atomic bombs were developed by the United States during World War II: a uranium-based device (codenamed "Little Boy") whose fissile material was highly enriched uranium, and a plutonium-based device (see Trinity test and "Fat Man") whose plutonium was derived from uranium-238. The uranium-based Little Boy device became the first nuclear weapon used in war when it was detonated over the Japanese city of Hiroshima on 6 August 1945. Exploding with a yield equivalent to 12,500 tonnes of TNT, the blast and thermal wave of the bomb destroyed nearly 50,000 buildings and killed approximately 75,000 people (see Atomic bombings of Hiroshima and Nagasaki). Initially it was believed that uranium was relatively rare, and that nuclear proliferation could be avoided by simply buying up all known uranium stocks, but within a decade large deposits of it were discovered in many places around the world.
qas: answers: text: Little Boy
question: What was the uranium-based bomb made by the US in World War II called?

answers: text: Fat Man
question: What was the codename of the plutonium-based bomb created in the Second World War?

answers: text: 6 August 1945
question: On what date was Little Boy detonated?

answers: text: 12,500
question: What was the equivalent yield in TNT of the Little Boy bomb, in tonnes?

answers: text: Hiroshima
question: Over what city was Little Boy detonated?

context: In 2005, seventeen countries produced concentrated uranium oxides, with Canada (27.9% of world production) and Australia (22.8%) being the largest producers and Kazakhstan (10.5%), Russia (8.0%), Namibia (7.5%), Niger (7.4%), Uzbekistan (5.5%), the United States (2.5%), Argentina (2.1%), Ukraine (1.9%) and China (1.7%) also producing significant amounts. Kazakhstan continues to increase production and may have become the world's largest producer of uranium by 2009 with an expected production of 12,826 tonnes, compared to Canada with 11,100 t and Australia with 9,430 t. In the late 1960s, UN geologists also discovered major uranium deposits and other rare mineral reserves in Somalia. The find was the largest of its kind, with industry experts estimating the deposits at over 25% of the world's then known uranium reserves of 800,000 tons.
qas: answers: text: Canada
question: As of 2005, what country was the largest producer of uranium oxides?

answers: text: 2.1%
question: What percentage of world uranium oxide production is produced by Argentina?

answers: text: Uzbekistan
question: What country produced 5.5% of the world's concentrated uranium oxide in 2005?

answers: text: seventeen
question: How many countries produced concentrated uranium oxides in 2005?

answers: text: 9,430
question: How many tonnes of uranium was Australia expected to produce in 2009?

context: During the Cold War between the Soviet Union and the United States, huge stockpiles of uranium were amassed and tens of thousands of nuclear weapons were created using enriched uranium and plutonium made from uranium. Since the break-up of the Soviet Union in 1991, an estimated 600 short tons (540 metric tons) of highly enriched weapons grade uranium (enough to make 40,000 nuclear warheads) have been stored in often inadequately guarded facilities in the Russian Federation and several other former Soviet states. Police in Asia, Europe, and South America on at least 16 occasions from 1993 to 2005 have intercepted shipments of smuggled bomb-grade uranium or plutonium, most of which was from ex-Soviet sources. From 1993 to 2005 the Material Protection, Control, and Accounting Program, operated by the federal government of the United States, spent approximately US $550 million to help safeguard uranium and plutonium stockpiles in Russia. This money was used for improvements and security enhancements at research and storage facilities. Scientific American reported in February 2006 that in some of the facilities security consisted of chain link fences which were in severe states of disrepair. According to an interview from the article, one facility had been storing samples of enriched (weapons grade) uranium in a broom closet before the improvement project; another had been keeping track of its stock of nuclear warheads using index cards kept in a shoe box.
qas: answers: text: United States
question: Who was the Soviet Union's opponent in the Cold War?

answers: text: 40,000
question: How many nuclear warheads can be made with 540 metric tons of highly enriched weapons grade uranium?

answers: text: US $550 million
question: What was the expenditure of the Material Protection, Control, and Accounting Program between 1993 and 2005?

answers: text: weapons grade
question: What is another term for uranium that is enriched?

answers: text: 16
question: Approximately how many times did police capture shipments of bomb-grade plutonium or uranium between 1993 and 2005?

context: Salts of many oxidation states of uranium are water-soluble and may be studied in aqueous solutions. The most common ionic forms are U3+ (brown-red), U4+ (green), UO+
2 (unstable), and UO2+
2 (yellow), for U(III), U(IV), U(V), and U(VI), respectively. A few solid and semi-metallic compounds such as UO and US exist for the formal oxidation state uranium(II), but no simple ions are known to exist in solution for that state. Ions of U3+ liberate hydrogen from water and are therefore considered to be highly unstable. The UO2+
2 ion represents the uranium(VI) state and is known to form compounds such as uranyl carbonate, uranyl chloride and uranyl sulfate. UO2+
2 also forms complexes with various organic chelating agents, the most commonly encountered of which is uranyl acetate.
qas: answers: text: green
question: What is the color of U4+?

answers: text: uranium(VI)
question: What state is represented by the UO2+ 2 ion?

answers: text: uranyl carbonate
question: Along with uranyl sulfate and uranyl chloride, what compound is formed by the UO2+ 2 ion?

answers: text: uranyl acetate
question: What common complex is formed by the UO2+ 2 ion with organic chelating agents?

context: Some organisms, such as the lichen Trapelia involuta or microorganisms such as the bacterium Citrobacter, can absorb concentrations of uranium that are up to 300 times the level of their environment. Citrobacter species absorb uranyl ions when given glycerol phosphate (or other similar organic phosphates). After one day, one gram of bacteria can encrust themselves with nine grams of uranyl phosphate crystals; this creates the possibility that these organisms could be used in bioremediation to decontaminate uranium-polluted water. The proteobacterium Geobacter has also been shown to bioremediate uranium in ground water. The mycorrhizal fungus Glomus intraradices increases uranium content in the roots of its symbiotic plant.
qas: answers: text: Citrobacter
question: What microorganism can notably absorb a very high concentrate of uranium?

answers: text: glycerol phosphate
question: What is given to Citrobacter to cause it to absorb uranyl ions?

answers: text: Trapelia involuta
question: What lichen is known to absorb a uranium concentration nearly 300 times higher than the amount in the environment?

answers: text: Geobacter
question: What protobacterium notably bioremediates ground water uranium?

answers: text: Glomus intraradices
question: What fungus is known to cause uranium content in its symbiotic plant roots to increase?

context: Uranium metal heated to 250 to 300 °C (482 to 572 °F) reacts with hydrogen to form uranium hydride. Even higher temperatures will reversibly remove the hydrogen. This property makes uranium hydrides convenient starting materials to create reactive uranium powder along with various uranium carbide, nitride, and halide compounds. Two crystal modifications of uranium hydride exist: an α form that is obtained at low temperatures and a β form that is created when the formation temperature is above 250 °C.
qas: answers: text: 482 to 572
question: At what temperature range in degrees Fahrenheit will uranium metal form uranium hydride?

answers: text: hydrogen
question: What does uranium metal react with to create uranium hydride?

answers: text: 250 °C
question: Above what temperature is the β form of uranium hydride created?

answers: text: nitride
question: Along with uranium carbide and halide, what type of compound is often created with uranium hydride?

answers: text: Two
question: How many crystal modifications of uranium hydride are extant?

context: Uranium carbides and uranium nitrides are both relatively inert semimetallic compounds that are minimally soluble in acids, react with water, and can ignite in air to form U
3O
8. Carbides of uranium include uranium monocarbide (UC), uranium dicarbide (UC
2), and diuranium tricarbide (U
2C
3). Both UC and UC
2 are formed by adding carbon to molten uranium or by exposing the metal to carbon monoxide at high temperatures. Stable below 1800 °C, U
2C
3 is prepared by subjecting a heated mixture of UC and UC
2 to mechanical stress. Uranium nitrides obtained by direct exposure of the metal to nitrogen include uranium mononitride (UN), uranium dinitride (UN
2), and diuranium trinitride (U
2N
3).
qas: answers: text: diuranium tricarbide
question: Along with uranium monocarbide and uranium dicarbide, what is a notable carbide of uranium?

answers: text: 1800 °C
question: Below what temperature is U2C3 stable?

context: To be considered 'enriched', the uranium-235 fraction should be between 3% and 5%. This process produces huge quantities of uranium that is depleted of uranium-235 and with a correspondingly increased fraction of uranium-238, called depleted uranium or 'DU'. To be considered 'depleted', the uranium-235 isotope concentration should be no more than 0.3%. The price of uranium has risen since 2001, so enrichment tailings containing more than 0.35% uranium-235 are being considered for re-enrichment, driving the price of depleted uranium hexafluoride above $130 per kilogram in July 2007 from $5 in 2001.
qas: answers: text: 3% and 5%
question: Between what percent fraction range of uranium-235 is uranium regarded as enriched?

answers: text: 2001
question: In what year did the cost of uranium notably begin to increase?

answers: text: 0.3%
question: What is the maximum uranium-235 isotope concentration for uranium to be considered depleted?

answers: text: $5
question: What was the price of a kilogram of depleted uranium hexafluoride in 2001?

answers: text: $130
question: How much did a kilogram of depleted uranium hexafluoride cost as of July 2007?

context: Normal functioning of the kidney, brain, liver, heart, and other systems can be affected by uranium exposure, because, besides being weakly radioactive, uranium is a toxic metal. Uranium is also a reproductive toxicant. Radiological effects are generally local because alpha radiation, the primary form of 238U decay, has a very short range, and will not penetrate skin. Uranyl (UO2+
2) ions, such as from uranium trioxide or uranyl nitrate and other hexavalent uranium compounds, have been shown to cause birth defects and immune system damage in laboratory animals. While the CDC has published one study that no human cancer has been seen as a result of exposure to natural or depleted uranium, exposure to uranium and its decay products, especially radon, are widely known and significant health threats. Exposure to strontium-90, iodine-131, and other fission products is unrelated to uranium exposure, but may result from medical procedures or exposure to spent reactor fuel or fallout from nuclear weapons. Although accidental inhalation exposure to a high concentration of uranium hexafluoride has resulted in human fatalities, those deaths were associated with the generation of highly toxic hydrofluoric acid and uranyl fluoride rather than with uranium itself. Finely divided uranium metal presents a fire hazard because uranium is pyrophoric; small grains will ignite spontaneously in air at room temperature.
qas: answers: text: kidney
question: Along with the heart, brain and liver, what system is notably affected by exposure to uranium?

answers: text: alpha radiation
question: What is the main form of 238U decay?

answers: text: hexavalent
question: What type of uranium compounds are uranium trioxide and uranyl nitrate?

answers: text: room
question: At what temperature will grains of uranium metal spontaneously ignite in air?

context: The gas centrifuge process, where gaseous uranium hexafluoride (UF
6) is separated by the difference in molecular weight between 235UF6 and 238UF6 using high-speed centrifuges, is the cheapest and leading enrichment process. The gaseous diffusion process had been the leading method for enrichment and was used in the Manhattan Project. In this process, uranium hexafluoride is repeatedly diffused through a silver-zinc membrane, and the different isotopes of uranium are separated by diffusion rate (since uranium 238 is heavier it diffuses slightly slower than uranium-235). The molecular laser isotope separation method employs a laser beam of precise energy to sever the bond between uranium-235 and fluorine. This leaves uranium-238 bonded to fluorine and allows uranium-235 metal to precipitate from the solution. An alternative laser method of enrichment is known as atomic vapor laser isotope separation (AVLIS) and employs visible tunable lasers such as dye lasers. Another method used is liquid thermal diffusion.
qas: answers: text: gas centrifuge
question: What is the name of the most widely used enrichment process?

answers: text: uranium hexafluoride
question: What compound is UF6?

answers: text: gaseous diffusion
question: What enrichment process was used by the Manhattan Project?

answers: text: uranium hexafluoride
question: In the gaseous diffusion process, what is diffused through a silver-zinc membrane?

answers: text: heavier
question: How does the weight of uranium-238 compare to that of uranium-235?

context: Uranium is a chemical element with symbol U and atomic number 92. It is a silvery-white metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium is weakly radioactive because all its isotopes are unstable (with half-lives of the six naturally known isotopes, uranium-233 to uranium-238, varying between 69 years and 4.5 billion years). The most common isotopes of uranium are uranium-238 (which has 146 neutrons and accounts for almost 99.3% of the uranium found in nature) and uranium-235 (which has 143 neutrons, accounting for 0.7% of the element found naturally). Uranium has the second highest atomic weight of the primordially occurring elements, lighter only than plutonium. Its density is about 70% higher than that of lead, but slightly lower than that of gold or tungsten. It occurs naturally in low concentrations of a few parts per million in soil, rock and water, and is commercially extracted from uranium-bearing minerals such as uraninite.
qas: answers: text: U
question: What is uranium's symbol on the Periodic Table of Elements?

answers: text: 92
question: What is the atomic number of uranium?

answers: text: silvery-white
question: What color is uranium?

answers: text: 6
question: How many valence electrons are contained in an atom of uranium?

answers: text: actinide
question: Of what series in the Periodic Table of Elements is uranium a part?

context: Uranium metal reacts with almost all non-metal elements (with an exception of the noble gases) and their compounds, with reactivity increasing with temperature. Hydrochloric and nitric acids dissolve uranium, but non-oxidizing acids other than hydrochloric acid attack the element very slowly. When finely divided, it can react with cold water; in air, uranium metal becomes coated with a dark layer of uranium oxide. Uranium in ores is extracted chemically and converted into uranium dioxide or other chemical forms usable in industry.
qas: answers: text: noble gases
question: What non-metal elements does uranium notably not react to?

answers: text: uranium oxide
question: What coats uranium metal in air?

answers: text: Hydrochloric
question: Along with nitric acids, what acids dissolve uranium?

answers: text: uranium dioxide
question: What is a notable form uranium ore is converted into after extraction?

answers: text: cold water
question: What reacts with finely divided uranium?

context: During the later stages of World War II, the entire Cold War, and to a lesser extent afterwards, uranium-235 has been used as the fissile explosive material to produce nuclear weapons. Initially, two major types of fission bombs were built: a relatively simple device that uses uranium-235 and a more complicated mechanism that uses plutonium-239 derived from uranium-238. Later, a much more complicated and far more powerful type of fission/fusion bomb (thermonuclear weapon) was built, that uses a plutonium-based device to cause a mixture of tritium and deuterium to undergo nuclear fusion. Such bombs are jacketed in a non-fissile (unenriched) uranium case, and they derive more than half their power from the fission of this material by fast neutrons from the nuclear fusion process.
qas: answers: text: World War II
question: During what war was uranium-235 first used to create nuclear weapons?

answers: text: 238
question: From what isotope of uranium is plutonium-239 derived?

answers: text: deuterium
question: What is mixed with tritium and experiences nuclear fusion in a fission/fusion bomb?

answers: text: thermonuclear weapon
question: What is another name for a fission/fusion bomb?

answers: text: unenriched
question: What does non-fissile mean?

context: Uranium was also used in photographic chemicals (especially uranium nitrate as a toner), in lamp filaments for stage lighting bulbs, to improve the appearance of dentures, and in the leather and wood industries for stains and dyes. Uranium salts are mordants of silk or wool. Uranyl acetate and uranyl formate are used as electron-dense "stains" in transmission electron microscopy, to increase the contrast of biological specimens in ultrathin sections and in negative staining of viruses, isolated cell organelles and macromolecules.
qas: answers: text: nitrate
question: What product of uranium was used as toner?

answers: text: Uranyl acetate
question: Along with uranyl formate, what product of uranium is used in transmission electron microscopy?

answers: text: stage
question: What light bulbs use lamp filaments containing uranium?

answers: text: wood
question: Along with leather, what industry uses uranium in dyes and stains?

answers: text: silk
question: In addition to wool, what is uranium salt a mordant of?

context: In 1972, the French physicist Francis Perrin discovered fifteen ancient and no longer active natural nuclear fission reactors in three separate ore deposits at the Oklo mine in Gabon, West Africa, collectively known as the Oklo Fossil Reactors. The ore deposit is 1.7 billion years old; then, uranium-235 constituted about 3% of the total uranium on Earth. This is high enough to permit a sustained nuclear fission chain reaction to occur, provided other supporting conditions exist. The capacity of the surrounding sediment to contain the nuclear waste products has been cited by the U.S. federal government as supporting evidence for the feasibility to store spent nuclear fuel at the Yucca Mountain nuclear waste repository.
qas: answers: text: French
question: Of what nationality was Perrin?

answers: text: Gabon
question: In what county was the Oklo mine located?

answers: text: 1.7 billion years
question: How old are the ore deposits in the Oklo mine?

answers: text: 3%
question: When the Oklo mine ore deposits came into being, what percentage of uranium on Earth consisted of uranium-235?

answers: text: Yucca Mountain
question: Where in the United States is there a nuclear waste repository?

context: Uranium's average concentration in the Earth's crust is (depending on the reference) 2 to 4 parts per million, or about 40 times as abundant as silver. The Earth's crust from the surface to 25 km (15 mi) down is calculated to contain 1017 kg (2×1017 lb) of uranium while the oceans may contain 1013 kg (2×1013 lb). The concentration of uranium in soil ranges from 0.7 to 11 parts per million (up to 15 parts per million in farmland soil due to use of phosphate fertilizers), and its concentration in sea water is 3 parts per billion.
qas: answers: text: 40
question: How many times more abundant than silver is uranium in the Earth's crust?

answers: text: 1013
question: How many kilograms of uranium may be contained in the oceans?

answers: text: phosphate fertilizers
question: Why is the concentrate of uranium in farmland so high?

answers: text: 3 parts per billion
question: What is the concentration of uranium in sea water?

context: Uranium-238 is the most stable isotope of uranium, with a half-life of about 4.468×109 years, roughly the age of the Earth. Uranium-235 has a half-life of about 7.13×108 years, and uranium-234 has a half-life of about 2.48×105 years. For natural uranium, about 49% of its alpha rays are emitted by each of 238U atom, and also 49% by 234U (since the latter is formed from the former) and about 2.0% of them by the 235U. When the Earth was young, probably about one-fifth of its uranium was uranium-235, but the percentage of 234U was probably much lower than this.
qas: answers: text: Uranium-238
question: What isotope of uranium has the most stability?

answers: text: 4.468×109 years
question: About how old is the Earth?

answers: text: 2.48×105 years
question: What is the half-life of uranium-234?

answers: text: one-fifth
question: What fraction of the Earth's uranium was uranium-235 during the Earth's youth?

answers: text: 49%
question: What percentage of the alpha rays of natural uranium are emitted by 234U?

context: Most ingested uranium is excreted during digestion. Only 0.5% is absorbed when insoluble forms of uranium, such as its oxide, are ingested, whereas absorption of the more soluble uranyl ion can be up to 5%. However, soluble uranium compounds tend to quickly pass through the body, whereas insoluble uranium compounds, especially when inhaled by way of dust into the lungs, pose a more serious exposure hazard. After entering the bloodstream, the absorbed uranium tends to bioaccumulate and stay for many years in bone tissue because of uranium's affinity for phosphates. Uranium is not absorbed through the skin, and alpha particles released by uranium cannot penetrate the skin.
qas: answers: text: excreted
question: What happens to a majority of ingested uranium?

answers: text: 5%
question: Up to what percentage of uranyl ion can be absorbed when ingested?

answers: text: 0.5%
question: About what percentage of uranium oxide is absorbed when ingested?

answers: text: phosphates
question: What does uranium have an affinity for?

answers: text: bone tissue
question: Where does uranium accumulate in the body?