rajpurkar/squad huggingface dataset:
Title: Aspirated_consonant

They are unaspirated for almost all speakers when immediately following word-initial s, as in spill, still, skill. After an s elsewhere in a word they are normally unaspirated as well, except sometimes in compound words. When the consonants in a cluster like st are analyzed as belonging to different morphemes (heteromorphemic) the stop is aspirated, but when they are analyzed as belonging to one morpheme the stop is unaspirated.[citation needed] For instance, distend has unaspirated [t] since it is not analyzed as two morphemes, but distaste has an aspirated middle [tʰ] because it is analyzed as dis- + taste and the word taste has an aspirated initial t.

Question: When following a word such as spill, they are what for most speakers?
Answer: unaspirated

Question: If the letter s is a different place in the word, it is typical unaspirated unless the word is what?
Answer: compound words

Question: If there is a cluster such as st and it belongs to different morphemes, the stop is what?
Answer: aspirated

Question: If the st belongs to one morpheme, then the stop is what?
Answer: unaspirated
Title: Aspirated_consonant

In many languages, such as Armenian, Korean, Thai, Indo-Aryan languages, Dravidian languages, Icelandic, Ancient Greek, and the varieties of Chinese, tenuis and aspirated consonants are phonemic. Unaspirated consonants like [p˭ s˭] and aspirated consonants like [pʰ ʰp sʰ] are separate phonemes, and words are distinguished by whether they have one or the other.

Question: In languages like Thai and Icelandic, tenuis and aspirated consonants are what?
Answer: phonemic

Question: [p˭ s˭] and [pʰ ʰp sʰ] are separate what?
Answer: phonemes
Title: Aspirated_consonant

In Danish and most southern varieties of German, the "lenis" consonants transcribed for historical reasons as ⟨b d ɡ⟩ are distinguished from their fortis counterparts ⟨p t k⟩, mainly in their lack of aspiration.

Question: How are lenis consonants distinguished from fortis consonants?
Answer: their lack of aspiration

Question: If the lenis are ⟨b d ɡ⟩, what are the fortis counterparts?
Answer: ⟨p t k⟩
Title: Aspirated_consonant

Standard Chinese (Mandarin) has stops and affricates distinguished by aspiration: for instance, /t tʰ/, /t͡s t͡sʰ/. In pinyin, tenuis stops are written with letters that represent voiced consonants in English, and aspirated stops with letters that represent voiceless consonants. Thus d represents /t/, and t represents /tʰ/.

Question: Mandarin has stops and affricates that are distinguished by what?
Answer: aspiration

Question: Tenuis stops have letters that are representative of English voiced consonant in what?
Answer: pinyin

Question: What kind of stops in pinyin are written with letters that representative of voiceless consonants?
Answer: aspirated stops
Title: Aspirated_consonant

Wu Chinese has a three-way distinction in stops and affricates: /p pʰ b/. In addition to aspirated and unaspirated consonants, there is a series of muddy consonants, like /b/. These are pronounced with slack or breathy voice: that is, they are weakly voiced. Muddy consonants as initial cause a syllable to be pronounced with low pitch or light (陽 yáng) tone.

Question: What has a three-way distinction in regards to stops and affricates?
Answer: Wu Chinese

Question: What is the actual distinction for Wu Chinese?
Answer: /p pʰ b/

Question: What is /b/ representative of, in addition to aspirated and unaspirated consonants?
Answer: Muddy consonants

Question: What kind of voice are muddy consonants pronounced with?
Answer: slack or breathy
Title: Aspirated_consonant

Many Indo-Aryan languages have aspirated stops. Sanskrit, Hindi, Bengali, Marathi, and Gujarati have a four-way distinction in stops: voiceless, aspirated, voiced, and breathy-voiced or voiced aspirated, such as /p pʰ b bʱ/. Punjabi has lost breathy-voiced consonants, which resulted in a tone system, and therefore has a distinction between voiceless, aspirated, and voiced: /p pʰ b/.

Question: How many distinctions in stops do languages like Bengali and Hindi have?
Answer: four

Question: What is another term for voice-aspirated?
Answer: breathy-voiced

Question: Which distinction has Punjabi lost?
Answer: breathy-voiced consonants
Title: Aspirated_consonant

Some of the Dravidian languages, such as Telugu, Tamil, Malayalam, and Kannada, have a distinction between voiced and voiceless, aspirated and unaspirated only in loanwords from Indo-Aryan languages. In native Dravidian words, there is no distinction between these categories and stops are underspecified for voicing and aspiration.

Question: Telegu, Kannada and others are considered to be some of the what languages?
Answer: Dravidian

Question: What has no distinction between the categories  of voiced, voiceless, aspirated and unaspirated?
Answer: native Dravidian words
Title: Aspirated_consonant

Western Armenian has a two-way distinction between aspirated and voiced: /tʰ d/. Western Armenian aspirated /tʰ/ corresponds to Eastern Armenian aspirated /tʰ/ and voiced /d/, and Western voiced /d/ corresponds to Eastern voiceless /t/.

Question: What language has two-way distinctions between aspirated and voiced?
Answer: Western Armenian

Question: Western Armenian /tʰ/ compares to eastern Armenian /tʰ/ and what?
Answer: /d/

Question: The Western Armenian voiced /d/ compares to the Eastern Armenian voiceless what?
Answer: /t/
Title: Aspirated_consonant

Some forms of Greek before the Koine Greek period are reconstructed as having aspirated stops. The Classical Attic dialect of Ancient Greek had a three-way distinction in stops like Eastern Armenian: /t tʰ d/. These stops were called ψιλά, δασέα, μέσα "thin, thick, middle" by Koine Greek grammarians.

Question: Early Greek (before Koine) have been redone with what?
Answer: aspirated stops.

Question: What Greek dialect had three-way stop distinction like Eastern Armenian?
Answer: Classical Attic

Question: Who referred to the Classical Attic dialect stops by the three distinctions?
Answer: Greek grammarians
Title: Aspirated_consonant

There were aspirated stops at three places of articulation: labial, coronal, and velar /pʰ tʰ kʰ/. Earlier Greek, represented by Mycenaean Greek, likely had a labialized velar aspirated stop /kʷʰ/, which later became labial, coronal, or velar depending on dialect and phonetic environment.

Question: What is the representation for the three places of articulation?
Answer: /pʰ tʰ kʰ/

Question: Earlier Greek was represented by what?
Answer: Mycenaean Greek

Question: Whether a stop was labial, coronal or velar depended on what two things?
Answer: dialect and phonetic environment
Title: Aspirated_consonant

The other Ancient Greek dialects, Ionic, Doric, Aeolic, and Arcadocypriot, likely had the same three-way distinction at one point, but Doric seems to have had a fricative in place of /tʰ/ in the Classical period, and the Ionic and Aeolic dialects sometimes lost aspiration (psilosis).

Question: Dialects such as Aeolic and Doric had how many distinctions that were the same at one point in time?
Answer: three

Question: Which two dialects lost aspiration at times?
Answer: Ionic and Aeolic

Question: Rather than /tʰ/, what did the Doric dialect have in place during the Classical period?
Answer: fricative
Title: Aspirated_consonant

Later, during the Koine Greek period, the aspirated and voiceless stops /tʰ d/ of Attic Greek lenited to voiceless and voiced fricatives, yielding /θ ð/ in Medieval and Modern Greek.

Question: Attic Greek lenited to what?
Answer: voiceless and voiced fricatives

Question: The lenited Attic Greek yielded /θ ð/ in what periods?
Answer: Medieval and Modern Greek
Title: Aspirated_consonant

The term aspiration sometimes refers to the sound change of debuccalization, in which a consonant is lenited (weakened) to become a glottal stop or fricative [ʔ h ɦ].

Question: Aspiration may refer to a sound change of what?
Answer: debuccalization

Question: Debuccalization is when consonants are weakened to become what?
Answer: glottal stop or fricative

Question: What is another term for a consonant being weakened?
Answer: lenited
Title: Aspirated_consonant

So-called voiced aspirated consonants are nearly always pronounced instead with breathy voice, a type of phonation or vibration of the vocal folds. The modifier letter ⟨◌ʰ⟩ after a voiced consonant actually represents a breathy-voiced or murmured dental stop, as with the "voiced aspirated" bilabial stop ⟨bʰ⟩ in the Indo-Aryan languages. This consonant is therefore more accurately transcribed as ⟨b̤⟩, with the diacritic for breathy voice, or with the modifier letter ⟨bʱ⟩, a superscript form of the symbol for the voiced glottal fricative ⟨ɦ⟩.

Question: What is breathy voice?
Answer: a type of phonation or vibration of the vocal folds

Question: The ⟨bʰ⟩ in the Indo-Aryan languages is better transcribed how for breathy voice?
Answer: ⟨b̤⟩, with the diacritic
Title: Aspirated_consonant

Some linguists restrict the double-dot subscript ⟨◌̤⟩ to murmured sonorants, such as vowels and nasals, which are murmured throughout their duration, and use the superscript hook-aitch ⟨◌ʱ⟩ for the breathy-voiced release of obstruents.

Question: What do some linguists restrict the double-dot subscript ⟨◌̤⟩ to?
Answer: murmured sonorants

Question: What are, according to the text, murmured for their duration?
Answer: vowels and nasals

Question: What uses the ⟨◌ʱ⟩?
Answer: breathy-voiced release of obstruents.
Title: Hydrogen

Hydrogen is a chemical element with chemical symbol H and atomic number 1. With an atomic weight of 7000100794000000000♠1.00794 u, hydrogen is the lightest element on the periodic table. Its monatomic form (H) is the most abundant chemical substance in the Universe, constituting roughly 75% of all baryonic mass.[note 1] Non-remnant stars are mainly composed of hydrogen in its plasma state. The most common isotope of hydrogen, termed protium (name rarely used, symbol 1H), has one proton and no neutrons.

Question: What is hydrogens chemical symbol?
Answer: H

Question: What is the atomic number used for hydrogen?
Answer: 1

Question: What is the atomic weight for hydrogen?
Answer: 7000100794000000000♠1.00794 u

Question: What element is considered the lightest?
Answer: Hydrogen
Title: Hydrogen

The universal emergence of atomic hydrogen first occurred during the recombination epoch. At standard temperature and pressure, hydrogen is a colorless, odorless, tasteless, non-toxic, nonmetallic, highly combustible diatomic gas with the molecular formula H2. Since hydrogen readily forms covalent compounds with most non-metallic elements, most of the hydrogen on Earth exists in molecular forms such as in the form of water or organic compounds. Hydrogen plays a particularly important role in acid–base reactions as many acid-base reactions involve the exchange of protons between soluble molecules. In ionic compounds, hydrogen can take the form of a negative charge (i.e., anion) when it is known as a hydride, or as a positively charged (i.e., cation) species denoted by the symbol H+. The hydrogen cation is written as though composed of a bare proton, but in reality, hydrogen cations in ionic compounds are always more complex species than that would suggest. As the only neutral atom for which the Schrödinger equation can be solved analytically, study of the energetics and bonding of the hydrogen atom has played a key role in the development of quantum mechanics.

Question: What form can you find hydrogen is on Earth?
Answer: molecular

Question: What is the molecular make-up of hydrogen?
Answer: H2

Question: What are three properties of hydrogen at normal temperature and normal pressure?
Answer: colorless, odorless, tasteless

Question: What charge does hydrogen display in ionic compounds when it is called a hydride?
Answer: negative

Question: What field of study has hydrogen and it's properties played a key role in development?
Answer: quantum mechanics
Title: Hydrogen

Hydrogen gas was first artificially produced in the early 16th century, via the mixing of metals with acids. In 1766–81, Henry Cavendish was the first to recognize that hydrogen gas was a discrete substance, and that it produces water when burned, a property which later gave it its name: in Greek, hydrogen means "water-former".

Question: When was hydrogen gas artificially produced for the first time?
Answer: early 16th century

Question: Who first recognized that hydrogen was a discrete substance?
Answer: Henry Cavendish

Question: When it is burned what does hydrogen make?
Answer: water

Question: What is the Greek translation for hydrogen?
Answer: water-former
Title: Hydrogen

Industrial production is mainly from the steam reforming of natural gas, and less often from more energy-intensive hydrogen production methods like the electrolysis of water. Most hydrogen is employed near its production site, with the two largest uses being fossil fuel processing (e.g., hydrocracking) and ammonia production, mostly for the fertilizer market. Hydrogen is a concern in metallurgy as it can embrittle many metals, complicating the design of pipelines and storage tanks.

Question: What market primarily uses ammonia production?
Answer: the fertilizer market

Question: Name a process that uses fossil fuels along with hydrogen.
Answer: hydrocracking
Title: Hydrogen

Hydrogen gas (dihydrogen or molecular hydrogen) is highly flammable and will burn in air at a very wide range of concentrations between 4% and 75% by volume. The enthalpy of combustion for hydrogen is −286 kJ/mol:

Question: For hydrogen what is the enthalpy of combustion?
Answer: 286 kJ/mol

Question: What are two forms of hydrogen gas?
Answer: dihydrogen or molecular hydrogen

Question: Which element has a enthalpy of combustion at −286 kJ/mol?
Answer: Hydrogen
Title: Hydrogen

Hydrogen gas forms explosive mixtures with air if it is 4–74% concentrated and with chlorine if it is 5–95% concentrated. The mixtures may be ignited by spark, heat or sunlight. The hydrogen autoignition temperature, the temperature of spontaneous ignition in air, is 500 °C (932 °F). Pure hydrogen-oxygen flames emit ultraviolet light and with high oxygen mix are nearly invisible to the naked eye, as illustrated by the faint plume of the Space Shuttle Main Engine compared to the highly visible plume of a Space Shuttle Solid Rocket Booster. The detection of a burning hydrogen leak may require a flame detector; such leaks can be very dangerous. Hydrogen flames in other conditions are blue, resembling blue natural gas flames. The destruction of the Hindenburg airship was an infamous example of hydrogen combustion; the cause is debated, but the visible orange flames were the result of a rich mixture of hydrogen to oxygen combined with carbon compounds from the airship skin.

Question: What kind of light do hydrogen-oxygen flames make?
Answer: ultraviolet light

Question: What caused  the Hindenburg to explode?
Answer: hydrogen combustion
Title: Hydrogen

H2 reacts with every oxidizing element. Hydrogen can react spontaneously and violently at room temperature with chlorine and fluorine to form the corresponding hydrogen halides, hydrogen chloride and hydrogen fluoride, which are also potentially dangerous acids.

Question: What are two other dangerous acids?
Answer: hydrogen chloride and hydrogen fluoride

Question: What temperature does hydrogen react with these elements?
Answer: room temperature
Title: Hydrogen

The energy levels of hydrogen can be calculated fairly accurately using the Bohr model of the atom, which conceptualizes the electron as "orbiting" the proton in analogy to the Earth's orbit of the Sun. However, the electromagnetic force attracts electrons and protons to one another, while planets and celestial objects are attracted to each other by gravity. Because of the discretization of angular momentum postulated in early quantum mechanics by Bohr, the electron in the Bohr model can only occupy certain allowed distances from the proton, and therefore only certain allowed energies.

Question: What model id used to calculate energy levels of hydrogen?
Answer: Bohr model

Question: What attracts planets and celestial items?
Answer: gravity

Question: What does the electromagnetic force attract to one another?
Answer: electrons and protons
Title: Hydrogen

A more accurate description of the hydrogen atom comes from a purely quantum mechanical treatment that uses the Schrödinger equation, Dirac equation or even the Feynman path integral formulation to calculate the probability density of the electron around the proton. The most complicated treatments allow for the small effects of special relativity and vacuum polarization. In the quantum mechanical treatment, the electron in a ground state hydrogen atom has no angular momentum at all—an illustration of how the "planetary orbit" conception of electron motion differs from reality.

Question: What kind of movement does the electron not have in ground state?
Answer: angular
Title: Hydrogen

There exist two different spin isomers of hydrogen diatomic molecules that differ by the relative spin of their nuclei. In the orthohydrogen form, the spins of the two protons are parallel and form a triplet state with a molecular spin quantum number of 1 (1⁄2+1⁄2); in the parahydrogen form the spins are antiparallel and form a singlet with a molecular spin quantum number of 0 (1⁄2–1⁄2). At standard temperature and pressure, hydrogen gas contains about 25% of the para form and 75% of the ortho form, also known as the "normal form". The equilibrium ratio of orthohydrogen to parahydrogen depends on temperature, but because the ortho form is an excited state and has a higher energy than the para form, it is unstable and cannot be purified. At very low temperatures, the equilibrium state is composed almost exclusively of the para form. The liquid and gas phase thermal properties of pure parahydrogen differ significantly from those of the normal form because of differences in rotational heat capacities, as discussed more fully in spin isomers of hydrogen. The ortho/para distinction also occurs in other hydrogen-containing molecules or functional groups, such as water and methylene, but is of little significance for their thermal properties.

Question: How many different spin isomers exist?
Answer: 2

Question: What state are the protons in when in the orthohydrogen form?
Answer: triplet state

Question: When hydrogen gas is in standard temperature and pressure, what form is it considered in>
Answer: normal

Question: What percent of para form does hydrogen gas contain?
Answer: 25%

Question: What percent of ortho form does hydrogen gas contain?
Answer: 75%
Title: Hydrogen

The uncatalyzed interconversion between para and ortho H2 increases with increasing temperature; thus rapidly condensed H2 contains large quantities of the high-energy ortho form that converts to the para form very slowly. The ortho/para ratio in condensed H2 is an important consideration in the preparation and storage of liquid hydrogen: the conversion from ortho to para is exothermic and produces enough heat to evaporate some of the hydrogen liquid, leading to loss of liquefied material. Catalysts for the ortho-para interconversion, such as ferric oxide, activated carbon, platinized asbestos, rare earth metals, uranium compounds, chromic oxide, or some nickel compounds, are used during hydrogen cooling.

Question: What are some catalysts used in hydrogen cooling
Answer: ferric oxide, activated carbon, platinized asbestos, rare earth metals, uranium compounds, chromic oxide, or some nickel compounds
Title: Hydrogen

While H2 is not very reactive under standard conditions, it does form compounds with most elements. Hydrogen can form compounds with elements that are more electronegative, such as halogens (e.g., F, Cl, Br, I), or oxygen; in these compounds hydrogen takes on a partial positive charge. When bonded to fluorine, oxygen, or nitrogen, hydrogen can participate in a form of medium-strength noncovalent bonding with other similar molecules between their hydrogens called hydrogen bonding, which is critical to the stability of many biological molecules. Hydrogen also forms compounds with less electronegative elements, such as the metals and metalloids, in which it takes on a partial negative charge. These compounds are often known as hydrides.

Question: What ind of charge does hydrogen take when mixed with electronegative particles?
Answer: positive charge

Question: What type of charge does hydrogen take when combined with a metal?
Answer: negative

Question: When hydrogen forms with a metal, what is the compound called?
Answer: hydrides

Question: Is H2 reactive in standard conditions?
Answer: not
Title: Hydrogen

Hydrogen forms a vast array of compounds with carbon called the hydrocarbons, and an even vaster array with heteroatoms that, because of their general association with living things, are called organic compounds. The study of their properties is known as organic chemistry and their study in the context of living organisms is known as biochemistry. By some definitions, "organic" compounds are only required to contain carbon. However, most of them also contain hydrogen, and because it is the carbon-hydrogen bond which gives this class of compounds most of its particular chemical characteristics, carbon-hydrogen bonds are required in some definitions of the word "organic" in chemistry. Millions of hydrocarbons are known, and they are usually formed by complicated synthetic pathways, which seldom involve elementary hydrogen.

Question: What is the form of hydrogen and carbon called?
Answer: hydrocarbons

Question: What is the form of hydrogen and heteroatoms called?
Answer: organic compounds

Question: What is the study of organic compounds properties known as?
Answer: organic chemistry

Question: What is the study of living organisms known as?
Answer: biochemistry

Question: Organic compounds are only required to conatin what?
Answer: carbon
Title: Hydrogen

Compounds of hydrogen are often called hydrides, a term that is used fairly loosely. The term "hydride" suggests that the H atom has acquired a negative or anionic character, denoted H−, and is used when hydrogen forms a compound with a more electropositive element. The existence of the hydride anion, suggested by Gilbert N. Lewis in 1916 for group I and II salt-like hydrides, was demonstrated by Moers in 1920 by the electrolysis of molten lithium hydride (LiH), producing a stoichiometry quantity of hydrogen at the anode. For hydrides other than group I and II metals, the term is quite misleading, considering the low electronegativity of hydrogen. An exception in group II hydrides is BeH
2, which is polymeric. In lithium aluminium hydride, the AlH−
4 anion carries hydridic centers firmly attached to the Al(III).

Question:  Who suggested that hydride anions existed?character does the H atom have in a hydride?
Answer: Gilbert N. Lewis

Question: What group of hydrides is BEH considered polymeric?
Answer: group II
Title: Hydrogen

Although hydrides can be formed with almost all main-group elements, the number and combination of possible compounds varies widely; for example, there are over 100 binary borane hydrides known, but only one binary aluminium hydride. Binary indium hydride has not yet been identified, although larger complexes exist.

Question: How many binary borane hydrides are known?
Answer: over 100

Question: How many binary aluminum hydrides are there?
Answer: 1
Title: Hydrogen

In inorganic chemistry, hydrides can also serve as bridging ligands that link two metal centers in a coordination complex. This function is particularly common in group 13 elements, especially in boranes (boron hydrides) and aluminium complexes, as well as in clustered carboranes.

Question: What chemistry do hydrides serve as bridging ligands?
Answer: inorganic chemistry

Question: What do hydrides that are bridging ligands link up?
Answer: link two metal centers

Question: What group is briging ligands most common in?
Answer: group 13