Teacher
experiment:
Petroleum
is a highly inflammable liquid. It needs strong heating to obtain Diesel
which has a higher boiling point.
* Left photo: Put
10 ml of petroleum into the 50-ml vial.
* Transfusion tubing is
twisted around a test tube and fixed by sticky tape.
* Both tubing ends are slipped
over the two pieces of drinking straw which were tightly fixed into
two stoppers.
* Close the 50-ml vial containing
petroleum by one of the stoppers, and the 5-ml vial 1 by the second stopper.
* To prevent building up
a positive pressure the right stopper is also punctured by a syringe hypodermic
needle.
* The test tube is filled
by small pieces of ice made in a muli cavity blister packing.
* The petroleum is not
directly heated on an electric hot plate but placed into a small
metallic container.
* Collect 1 ml liquid
in the right vial, then replace it by vials 2, 3,4.
Observations
Right: Petroleum
starts boiling earlier than water. The vapour will condense
inside the transfusion tubing. Transparent liquids condense
in the tubing and then drops into vials 1, 2, 3, 4.