Editing Dalton's law

{{Short description|Empirical law of partial pressures}}
[[File:Dalton's law of partial pressures.svg|thumb|upright=1.75|An illustration of Dalton's law using the gases of air at sea level.]]
'''Dalton's law''' (also called '''Dalton's law of partial pressures''') states that in a mixture of non-reacting gases, the total  [[pressure]] exerted is equal to the sum of the [[partial pressure]]s of the individual gases.<ref name="Silberberg">{{cite book |last=Silberberg |first=Martin S. |date=2009 |title=Chemistry: the molecular nature of matter and change |url=https://archive.org/details/chemistrymolecul00silb_143 |url-access=limited |edition=5th |publisher=McGraw-Hill |location=Boston |isbn=9780073048598 |page=[https://archive.org/details/chemistrymolecul00silb_143/page/n234 206] |ref=1}}</ref> This [[empirical]] law was observed by [[John Dalton]] in 1801 and published in 1802.<ref>J. Dalton (1802), [https://books.google.com/books?id=3qdJAAAAYAAJ&pg=PA595 "Essay IV.  On the expansion of elastic fluids by heat,"] ''Memoirs of the Literary and Philosophical Society of Manchester'', vol. 5, pt. 2, pages 595–602; see page 600.</ref> Dalton's law is related to the [[ideal gas|ideal]] [[gas laws]].

==Formula==
Mathematically, the pressure of a mixture of non-[[chemical reaction|reactive]] gases can be defined as the summation:
<math display="block">p_\text{total} = \sum_{i=1}^n p_i = p_1+p_2+p_3+\cdots+p_n</math>
where {{math|''p''<sub>1</sub>}}, {{math|''p''<sub>2</sub>}}, ..., {{math|''p<sub>n</sub>''}} represent the partial pressures of each component.<ref name="Silberberg" />

<math display="block">p_{i} = p_\text{total} x_i</math>
where {{math|''x<sub>i</sub>''}} is the [[mole fraction]] of the ''i''th component in the total mixture of ''n'' components.

==Volume-based concentration==
The relationship below provides a way to determine the [[concentration|volume-based concentration]] of any individual gaseous component
<math display="block">p_i = p_\text{total} c_i</math>
where ''c<sub>i</sub>'' is the concentration of component ''i''.

Dalton's law is not strictly followed by real gases, with the deviation increasing with pressure. Under such conditions the volume occupied by the molecules becomes significant compared to the free space between them. In particular, the short average distances between molecules increases [[intermolecular force]]s between gas molecules enough to substantially change the pressure exerted by them, an effect not included in the ideal gas model.

==See also== 
{{Div col|small=yes}}
* {{annotated link|Amagat's law}}
* {{annotated link|Boyle's law}}
* {{annotated link|Combined gas law}}
* {{annotated link|Gay-Lussac's law}}
* {{annotated link|Henry's law}}
* {{annotated link|Mole (unit)}}
* {{annotated link|Partial pressure}}
* {{annotated link|Raoult's law}}
* {{annotated link|Vapor pressure}}
{{Div col end}}

==References==
{{Reflist}}

{{Distillation}}
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[[Category:Gas laws]]
[[Category:Physical chemistry]]
[[Category:Engineering thermodynamics]]

[[de:Partialdruck#Dalton-Gesetz]]
[[et:Daltoni seadus]]