290 ELEMENTS OF GROUP IV
Make mixtures of gasoline and carbon tetrachloride in the
proportion of 5 cc. and 1 cc.; 4 cc. and 2 cc.; 3 cc. and 3 cc.;
2 cc. and 4 cc; 1 cc. and 5 cc, and under the hood apply a
lighted match to each. If the mixture does not at once catch
fire, heat it to its boiling point, and try again.
Place 1 cc. of gasoline and 5 cc. of water in the dish and
apply a lighted match.Gasoline is a mixture of hydrocarbons, that is compounds of
carbon and hydrogen, of which hexane C 6 HH, heptane C7II16,
and octane CsHis, are the principal ones. Gasoline and carbon
disulphide are very combustible. Carbon tetrachloride and
chloroform do not burn.
Carbon tetrachloride and gasoline are mutually soluble in each
other in all proportions. The vapor pressure of gasoline is lowered
by the admixture, and furthermore the vapor that escapes is mixed
with non-combustible carbon tetrachloride vapor; it is thus
understandable that the combustibility of gasoline is lessened by
large admixture with this substance.
Gasoline and water do not mix, but the former will float in a
layer over the latter; water is of little effect in extinguishing a
gasoline fire.
- Carbon Monoxide. Place a plug of shredded asbestos
loosely 2 inches from one end of a combustion tube. Fill
the tube with granulated (not powdered) charcoal for a
length of about 4 inches, and insert another plug of asbestos.
Join this tube to a carbon dioxide generator, and let the gas
flow until air is completely expelled from the apparatus.
Draw out the end of a delivery tube to a fine capillary in order
that it may deliver very small bubbles of gas, and connect
this by means of a rubber tube with the other end of the tube
containing the charcoal. Place a little 6N NaOH in a shal-
low dish; fill a test tube with the same solution, and invert
the tube in the solution in the dish. Have the generator de-
livering a very slow stream of carbon dioxide, and insert the
delivery tube under the mouth of the test tube. The carbon
dioxide should be completely absorbed in rising through the
NaOH solution. If it is not, it must not be delivered so
rapidly by the generator. Now heat the charcoal as hot as