Utente:Grasso Luigi/sanbox1/Frazione (chimica)

A fraction in chemistry is a quantity collected from a sample or batch of a substance in a fractionating separation process. In such a process, a mixture is separated into fractions, which have compositions that vary according to a gradient.

A fraction can be defined as a group of chemicals that have similar boiling points. A common fractionating process is fractional distillation. It is used to produce liquor and various hydrocarbon fuels, such as gasoline, kerosene and diesel.

A fraction is the product of a fractionating column. A vast chamber designed to separate different substances based on their boiling point, e.g. crude oil.

Fraction could also refer to a description of the composition of a mixture, e.g. mass fraction or mole fraction.

For a simpler definition a fraction is a part of the fractionating column where a compound with one boiling point can be separated from other compounds with different boiling points.

Esempi

Esempi sono la CO2frazione nell'aria espirata, l'O2 frazione dell'aria di inalazione (FiO2, → ventilazione), la frazione olio leggero di petrolio greggio , nella biochimica della proteina frazione del latte o organelli frazioni nella lavorazione di tessuti biologici così come le proteine solubili da un lato e le frazioni di membrana insolubile dall'altro lato nella sottofrazione degli organelli (o in generale dei sistemi basati su membrane ).