176
EQUILIBRIUM OF HETEROGENEOUS SUBSTANCES.
2pressure may by (263) be expressed by the formula
, the relative density of a binary gas-mixture may be expressed by
|
(326)
|
Now by (263)
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(327)
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By giving to
and
successively the value zero in these equations, we obtain
![{\displaystyle D_{1}={\frac {a_{s}}{a_{1}}},}](https://wikimedia.org/api/rest_v1/media/math/render/svg/a617cca0a99f94897180a8209532323d9aa2657d)
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(328)
|
where
and
denote the values of
when the gas consists wholly of one or of the other component. If we assume that
|
(329)
|
we shall have
|
(330)
|
From (326) we have
and from (327), by (328) and (330),
|
|
whence
|
(331)
|
|
(332)
|
By (327), (331), and (332) we obtain from (320)
|
(333)
|
This formula will be more convenient for purposes of calculation if we introduce common logarithms (denoted by
) instead of hyperbolic, the temperature of the ordinary centigrade scale
instead of the absolute temperature
, and the pressure in atmospheres
instead of
the pressure in a rational system of units. If we also add the logarithm of
to both sides of the equation, we obtain
|
(334)
|
where
and
denote constants, the values of which are closely connected with those of
and
.
From the molecular formulæ of peroxide of nitrogen NO2 and N2O4, we may calculate the relative densities
and
|
(335)
|