Chemistry Reference
In-Depth Information
concentration in the air. A part of the hydroxide ions OH
is replaced by carbonate
ions CO
2
3
as follows:
2OH
solution
!
CO
2
3 solution
þ
CO
2 gas phase
þ
H
2
O
liquid phase
This reaction unavoidably implies the decrease of the concentration of the caustic
solution over time, which, in turn, distorts chemical quantification during acid-base
titrations if it is not taken into account. While maintaining all other conditions the
same concentrated sulphuric acid is far more stable than caustic soda when in
contact with the air. The context of application and content of the
ceteris paribus
clause thus differ because of the different reactivity of bodies and their degree of
stability which, we have shown it, is closely related to the surroundings. The notion
of “fixity” and that of “identity” which traditionally enable scientists to make
inferences from comparison can easily become problematic. The content of the
ceteris paribus
clause becomes an object of inquiry as soon as one aims to
elucidate the meaning of the clause in actual chemical contexts.
In agreement with our previous arguments,
it is impossible to abstract the body
from the operative framework in which it is stored or used
. Accordingly, the
practice of inserting a
ceteris paribus
clause cannot deal with any particular
reaction of the same body in all circumstances but is, by contrast, primarily
concerned with what we shall call the couple {bodies-associated milieu}. The
associated milieu can be a solvent or a mixture of solvents, a gas vector, a mineral
matrix,
2
and so on.
Only one parameter must vary in order to characterize the chemical behavior of
this couple in relation to the qualification “all things being equal.” In this respect,
the use of the clause does not permit any nomological implication in connection
with the intrinsic properties of bodies. The conclusion of chemical reasoning
is about the couple {chemical bodies-associated milieu} under study. Both relations
and
relata
are thus taken into account at the same time. We have called this
Requisite 1 above.
We have now to include the instrumentation that enables chemists to quantify
their products in our investigation. We cannot consider the mode of access-
apparatus-as a transparent window through which to see the world as it would
have existed had the mode of access never been constructed and switched on, which
we have called Requisite 2 above. Science is the study of
'
apparatus/world com-
plexes
s isolation of sodium in the metallic state by
electrolysis of a solution which contains Na
+
cations is an example of such an
apparatus/world complex. It is always possible to claim that an apparatus makes
actual in the laboratory that which is potential in nature (Wallace
1996
; Cartwright
1989
). This reasoning is just another way of considering the apparatus as a kind of
window on the world. Such windows do not reveal any actual thing but, on the
(Harr´
2004
). Humphrey Davy
'
'
2
The term matrix describes the substrate in which the molecules to be characterized and titrated
are located (e.g. biological fluid, vegetable matter, etc.).
