Context and question: 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:
Which element has a enthalpy of combustion at −286 kJ/mol?
Answer: Hydrogen
Context and question: The value judgement definition of literature considers it to exclusively include writing that possesses high quality or distinction, forming part of the so-called belles-lettres ('fine writing') tradition. This is the definition used in the Encyclopædia Britannica Eleventh Edition (1910–11) when it classifies literature as "the best expression of the best thought reduced to writing." However, this has the result that there is no objective definition of what constitutes "literature"; anything can be literature, and anything which is universally regarded as literature has the potential to be excluded, since value-judgements can change over time.
What is the main component of the qualitative judgment definition of literature?
Answer: writing that possesses high quality or distinction
Context and question: There are three classes of components for oxide glasses: network formers, intermediates, and modifiers. The network formers (silicon, boron, germanium) form a highly cross-linked network of chemical bonds. The intermediates (titanium, aluminium, zirconium, beryllium, magnesium, zinc) can act as both network formers and modifiers, according to the glass composition. The modifiers (calcium, lead, lithium, sodium, potassium) alter the network structure; they are usually present as ions, compensated by nearby non-bridging oxygen atoms, bound by one covalent bond to the glass network and holding one negative charge to compensate for the positive ion nearby. Some elements can play multiple roles; e.g. lead can act both as a network former (Pb4+ replacing Si4+), or as a modifier.
What type of components change the oxygen atoms?
Answer:
unanswerable