sentence-transformers/squad huggingface dataset:
Passage: 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).

Question: What is uranium used for most often in the military?

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

Question: What percentage of high-density penetrators is not made up of depleted uranium?

Question: Along with the Balkans, in what geographical location did a war take place where the UK used depleted uranium munitions?

Question: What illness is possibly tied to the use of depleted uranium munitions?
Passage: 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.

Question: Who discovered uranium?

Question: In what year did the discovery of uranium occur?

Question: In what city was uranium discovered?

Question: What did Klaproth probably create when he dissolved pitchblende in nitric acid?

Question: Who discovered the planet Uranus?
Passage: 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.

Question: What percentage range of uranium oxide is usually contained in low-grade uranium ore?

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

Question: In what country are high-grade uranium ores notably found?

Question: In what province of Canada is the Athabasca Basin?

Question: What is the average percentage of uranium oxide contained in the ores mined in the Athabasca Basin?
Passage: 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.

Question: What was the uranium-based bomb made by the US in World War II called?

Question: What was the codename of the plutonium-based bomb created in the Second World War?

Question: On what date was Little Boy detonated?

Question: What was the equivalent yield in TNT of the Little Boy bomb, in tonnes?

Question: Over what city was Little Boy detonated?
Passage: 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.

Question: As of 2005, what country was the largest producer of uranium oxides?

Question: What percentage of world uranium oxide production is produced by Argentina?

Question: What country produced 5.5% of the world's concentrated uranium oxide in 2005?

Question: How many countries produced concentrated uranium oxides in 2005?

Question: How many tonnes of uranium was Australia expected to produce in 2009?
Passage: 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.

Question: Who was the Soviet Union's opponent in the Cold War?

Question: How many nuclear warheads can be made with 540 metric tons of highly enriched weapons grade uranium?

Question: What was the expenditure of the Material Protection, Control, and Accounting Program between 1993 and 2005?

Question: What is another term for uranium that is enriched?

Question: Approximately how many times did police capture shipments of bomb-grade plutonium or uranium between 1993 and 2005?
Passage: 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.

Question: What is the color of U4+?

Question: What state is represented by the UO2+ 2 ion?

Question: Along with uranyl sulfate and uranyl chloride, what compound is formed by the UO2+ 2 ion?

Question: What common complex is formed by the UO2+ 2 ion with organic chelating agents?
Passage: 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.

Question: What microorganism can notably absorb a very high concentrate of uranium?

Question: What is given to Citrobacter to cause it to absorb uranyl ions?

Question: What lichen is known to absorb a uranium concentration nearly 300 times higher than the amount in the environment?

Question: What protobacterium notably bioremediates ground water uranium?

Question: What fungus is known to cause uranium content in its symbiotic plant roots to increase?
Passage: 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.

Question: At what temperature range in degrees Fahrenheit will uranium metal form uranium hydride?

Question: What does uranium metal react with to create uranium hydride?

Question: Above what temperature is the β form of uranium hydride created?

Question: Along with uranium carbide and halide, what type of compound is often created with uranium hydride?

Question: How many crystal modifications of uranium hydride are extant?
Passage: 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).

Question: Along with uranium monocarbide and uranium dicarbide, what is a notable carbide of uranium?

Question: Below what temperature is U2C3 stable?
Passage: 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.

Question: Between what percent fraction range of uranium-235 is uranium regarded as enriched?

Question: In what year did the cost of uranium notably begin to increase?

Question: What is the maximum uranium-235 isotope concentration for uranium to be considered depleted?

Question: What was the price of a kilogram of depleted uranium hexafluoride in 2001?

Question: How much did a kilogram of depleted uranium hexafluoride cost as of July 2007?
Passage: 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.

Question: Along with the heart, brain and liver, what system is notably affected by exposure to uranium?

Question: What is the main form of 238U decay?

Question: What type of uranium compounds are uranium trioxide and uranyl nitrate?

Question: At what temperature will grains of uranium metal spontaneously ignite in air?
Passage: 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.

Question: What is the name of the most widely used enrichment process?

Question: What compound is UF6?

Question: What enrichment process was used by the Manhattan Project?

Question: In the gaseous diffusion process, what is diffused through a silver-zinc membrane?

Question: How does the weight of uranium-238 compare to that of uranium-235?
Passage: 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.

Question: What is uranium's symbol on the Periodic Table of Elements?

Question: What is the atomic number of uranium?

Question: What color is uranium?

Question: How many valence electrons are contained in an atom of uranium?

Question: Of what series in the Periodic Table of Elements is uranium a part?
Passage: 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.

Question: What non-metal elements does uranium notably not react to?

Question: What coats uranium metal in air?

Question: Along with nitric acids, what acids dissolve uranium?

Question: What is a notable form uranium ore is converted into after extraction?

Question: What reacts with finely divided uranium?
Passage: 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.

Question: During what war was uranium-235 first used to create nuclear weapons?

Question: From what isotope of uranium is plutonium-239 derived?

Question: What is mixed with tritium and experiences nuclear fusion in a fission/fusion bomb?

Question: What is another name for a fission/fusion bomb?

Question: What does non-fissile mean?
Passage: 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.

Question: What product of uranium was used as toner?

Question: Along with uranyl formate, what product of uranium is used in transmission electron microscopy?

Question: What light bulbs use lamp filaments containing uranium?

Question: Along with leather, what industry uses uranium in dyes and stains?

Question: In addition to wool, what is uranium salt a mordant of?
Passage: 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.

Question: Of what nationality was Perrin?

Question: In what county was the Oklo mine located?

Question: How old are the ore deposits in the Oklo mine?

Question: When the Oklo mine ore deposits came into being, what percentage of uranium on Earth consisted of uranium-235?

Question: Where in the United States is there a nuclear waste repository?
Passage: 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.

Question: How many times more abundant than silver is uranium in the Earth's crust?

Question: How many kilograms of uranium may be contained in the oceans?

Question: Why is the concentrate of uranium in farmland so high?

Question: What is the concentration of uranium in sea water?
Passage: 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.

Question: What isotope of uranium has the most stability?

Question: About how old is the Earth?

Question: What is the half-life of uranium-234?

Question: What fraction of the Earth's uranium was uranium-235 during the Earth's youth?

Question: What percentage of the alpha rays of natural uranium are emitted by 234U?
Passage: 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.

Question: What happens to a majority of ingested uranium?

Question: Up to what percentage of uranyl ion can be absorbed when ingested?

Question: About what percentage of uranium oxide is absorbed when ingested?

Question: What does uranium have an affinity for?

Question: Where does uranium accumulate in the body?