Where does regional metamorphism usually occur ?

Chemistry

1 answer:

Alex Ar [27]3 years ago

3 0

Answer:

Regional metamorphic rocks form from other rocks (protoliths) by changes in mineralogy and texture in response to changing physical conditions (temperature, lithostatic pressure, and, in most cases, shear stress). Regional metamorphism occurs over broad areas in the lithosphere, possibly influenced by the heat supply. Regional metamorphic rock results from regional metamorphism and usually develops a flaky texture. These changes are essentially solid-state reactions, but very often a fluid phase is present, either participating in the reaction or as a reaction medium. Many regional metamorphic rocks have a chemical composition that is very similar to that of their sedimentary or igneous precursors, with the exception of removal or addition of volatiles (mainly H2O and CO2). This type of behavior is termed isochemical metamorphism. Metamorphism may also take place as a result of a change in chemical environment; this may occur by transport of elements between chemically contrasting rock types (e.g., formation of calc-silicate minerals at a quartzite–marble contact) or by circulation of fluids that dissolve some substances and precipitate others. This process of significant chemical change during metamorphism is known as allo-chemical metamorphism or metasomatism, and rocks formed in this manner are metasomatic rocks. Metasomatism is, however, mostly of local significance, and the total volume of metasomatic rocks in regional metamorphic terranes is rather minor. The distinction between metasomatism and is chemical metamorphism is also a matter of scale. On the scale of individual grains, mass transport takes place during all phase transformations; on the scale of a thin section, it is probably the rule for regional metamorphism; on the scale of a hand (sized) specimen, it can be observed frequently; and on a larger scale, it is the exception.

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Which liquid has the highest vapor pressure at 75°C?

Temka [501]

Answer:

1) Ethanol

Explanation:

If we will have interactions we will need more energy to break them in order to go from liquid to gas. If we need more energy, therefore, the temperature will be higher.

In this case, we can discard the propanone because this molecule don't have the ability to form hydrogen bonds. (Let's remember that to have hydrogen bonds we need to have a hydrogen bond to a heteroatom, O, N, P or S).

Then we have to analyze the hydrogen bonds formed in the other molecules. For ethanol, we will have only 1 hydrogen bond. For water and ethanoic acid, we will have 2 hydrogen bonds, therefore, we can discard the ethanol.

For ethanoic acid, we have 2 intramolecular hydrogen bonds. For water we have 2 intermolecular hydrogen bonds, therefore, the strongest interaction will be in the ethanoic acid.

The closer boiling point to the 75ºC is the ethanol (boiling point of 78.8 ºC) therefore these molecules would have enough energy to break the hydrogen bonds and to past from liquid to gas.