Synthetic Inorganic Chemistry

138 NON-METALLIC ELEMENTS IN BINARY COMPOUNDS

Materials: copper metal (turnings or wire), 13 grams = 0.2

F.W.

6 N HNO 3 , 88 cc.

anhydrous sodium carbonate, Na2CO 3 , 30 grams.

Apparatus: 2-liter common bottle.

5-inch funnel.

8-inch porcelain dish.

4-inch porcelain dish.

600-cc. beaker.

Bunsen burner,

iron ring and ring stand.

Procedure: Put the copper in a 600-cc. beaker and under the
hood add the nitric acid in small portions until solution is com-
plete; observe Note 7, page 13. The mixture may be heated
toward the end of the reaction if necessary. When all the copper
has dissolved add 200 cc. of water and filter the solution, if it is not
clear, into an 8-inch porcelain evaporating dish.
Dissolve 30 grams of anhydrous sodium carbonate in 300 cc. of
water. Filter the solution if it is not clear. Pour 250 cc. of this
solution into the copper nitrate solution. Stir the mixture and
heat to boiling. The solid should turn nearly black. If this does
not happen add small portions of the sodium carbonate solution
until it does. Boil and stir the mixture for about 3 minutes.
Allow the solid to settle in the dish and pour off most of the liquid.
Stir up the solid with the remainder of the liquid and pour it into
approximately a liter of cold water in a 2-liter bottle. Wash the
solid by decantation until the soluble salts are reduced to less than
one one-thousandth of the original concentration. (Estimate the
volume of liquid poured into the bottle with the solid the first
time. Follow Note 5 (6), page 10.)
Pour the solid onto a filter and allow it to drain as completely as
possible. Spread the paper and its contents on a watch glass and
continue the drying on the hot plate. Separate the black basic
copper carbonate from the paper and place it in a 4-inch porcelain
evaporating dish. Heat with a small flame, and stir the solid with
a glass rod. A low temperature suffices to decompose the basic
carbonate. When the solid has changed to a uniform black powder
test it for carbonate. Place about 0.1 gram in a test tube, cover it
with 5 cc. of water, and heat to the boiling temperature. We now