RATIO OF HYDROGEN AND OXYGEN IN WATER 31which it combines, and then through another calcium chloride
tube to absorb the water vapor formed.
Materials: copper oxide, fine wire form,
feathered zinc,
anhydrous calcium chloride.
6 N hydrochloric acid.
Apparatus: Pyrex combustion tube, 10 inch,
two 4-inch side arm U-tubes.
porcelain boat.
8-ounce common bottle,
thistle tube,
rubber stoppers.
Bunsen burner,
two 4-inch iron rings.
2 ring stands,
cotton.Data Form:
Weight of boat + copper oxide before reaction. grams
Weight of boat + copper after reaction grams
Weight of oxygen grams
Weight of U-tube after reaction grams
Weight of U-tube before reaction grams
Weight of water formed gramsProcedure: While setting up the apparatus as shown in Fig. 12
heat 5 or 6 grams of copper oxide to redness in a porcelain boat
so as to drive off any water it may contain. Place about 30 grams
of feathered zinc in an 8-ounce bottle. Through a tight-fitting,
two-hole rubber stopper pass a thistle tube reaching to the bottom
and an elbow tube just entering the top of the bottle. Fill each
of the U-tubes with granular calcium chloride to within 2 cm. of
the side arms, and insert a loose plug of cotton on top of the
calcium chloride on each side. Attach one of the U-tubes to the
generator tube on one side and the combustion tube on the other.
The latter should slope downward at an angle of 5° to 10°.
The other end of the combustion tube is attached to the second
drying tube. The two ends of the glass tubes should touch under
the short rubber connector. The second calcium chloride tube