85 deg. C. If the laws of solution were identically the same for a
solution of sea-salt, the same depression should be noticed in a
saline solution also containing 1 molecule per litre. In fact, the
fall reaches 3.26 deg., and the solution behaves as if it contained, not
1, but 1.75 normal molecules per litre. The consideration of the
osmotic pressures would lead to similar observations, but we know that
the experiment would be more difficult and less precise.
We may wonder whether anything really analogous to this can be met with
in the case of a gas, and we are thus led to consider the phenomena of
dissociation.[18] If we heat a body which, in a gaseous state, is
capable of dissociation--hydriodic acid, for example--at a given
temperature, an equilibrium is established between three gaseous bodies,
the acid, the iodine, and the hydrogen. The total mass will follow with
fair closeness Mariotte's law, but the characteristic constant will no
longer be the same as in the case of a non-dissociated gas. We here no
longer have to do with a single molecule, since each molecule is in part
dissociated.
Pages:
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214