Synthetic Inorganic Chemistry

36 QUANTITATIVE ASPECTS OF CHEMISTRY

to fill the bulb. To this end, while the sealed bulb is being cooled
and weighed, boil about 300 cc. of distilled water in an 8-inch por-
celain evaporating dish, and cool it rapidly. After the sealed bulb
has been weighed, immerse the stem in the air-free water and break
off the tip of the stem. Water will rush into the bulb and fill it
practically completely if the preceding manipulation has been
skilfully performed. If more than 3 cc. of air is found in the bulb,
reject your data to this point and start the experiment again.
The weight of the condensed carbon tetrachloride left in the bulb
may be neglected as it is very small in comparison with that of the
water.

Perform the experiment a second time, starting with a dry
bulb. From your data make the following calculations for each
of the duplicate determinations:

1. The volume of the bulb (c-a), neglecting the weight of air
   in the bulb and the coefficient of expansion of the glass.


2. Reduce to standard conditions the volume of vapor in the
   bulb at the recorded bath temperature and pressure (assuming
   that the vapor would not condense) (vst CCU).


3. Reduce to standard conditions the volume of air in the bulb
   when it was weighed (yst air), and find the weight of this air,
   using 1.293 as the weight of a liter of air (d).


4. The actual weight of the empty bulb (a-d) (e).


5. The weight of carbon tetrachloride vapor (6-e).


6. The molecular weight of carbon tetrachloride.

Notes and Problems
The law of definite proportions states that whenever two (or
more) elements combine to form a definite compound the ratio
by weight of the elements entering that compound is always the
same.
The law of multiple proportions covers the case where two (or
more) elements form more than one definite compound. The law
of definite proportions applies to each of the compounds, and the
law of multiple proportions says that the definite ratios for the
separate compounds are to each other in the ratio of small inte-
gral numbers.
Perhaps the most easily visualized statement of the law of
multiple proportions is as follows: If the same weight of one ele-