Synthesis of oxygen

Preparation of oxygen

Preparation of oxygen from potassium chlorate and manganese(IV) oxide

Preparation of oxygen from potassium chlorate and manganese(IV) oxide

Preparation of oxygen from potassium chlorate and manganese(IV) oxide

The two ingredients – potassium chlorate and manganese(IV) oxide must be pulverized and thoroughly dried. Twenty g of each are intimately mixed and placed in a 250 ml glass Erlenmeyer flask fitted with a stopper and a rather wide glass elbow, and clamped on a ring-stand. To the elbow is attached a rubber tube fitted with a glass elbow at the other end, which permits of a free movement of the tube in the pneumatic, trough. On gradually increasing the heat, a rapid, though steady, evolution of oxygen ensues. At the end of the reaction, the tube must be removed from the pneumatic trough to prevent the back suction of the water. The purity of the manganese dioxide is of considerable importance, as an admixture of carbonaceous matter of any nature is likely to cause an explosion.

Chemical lecture experiments, by F. G. Benedict, 11, 1916.

Preparation of oxygen from sodium peroxide

Preparation of oxygen from sodium peroxide

Preparation of oxygen from sodium peroxide

Water decomposes sodium peroxide with the formation of sodium hydroxide and oxygen. If water in a dropping-funnel is allowed to fall, drop by drop, on 5 g of dry sodium peroxide in a dry 100 ml Erlenmeyer flask fitted with a delivery-tube, a steady evolution of pure oxygen is secured.

A glass apparatus for the preparation of oxygen

A glass apparatus for the preparation of oxygen

The yield of oxygen is very good, 6.25 g of the sodium peroxide giving 1 liter of the oxygen gas. The regulation of the flow of oxygen is nearly perfect, as each drop of water generates a certain amount of oxygen; thus a few centimeters or an almost unlimited volume per minute can be obtained by simple regulation of water supply. Only a small quantity of water, however, is necessary to decompose the peroxide.

Chemical lecture experiments, by F. G. Benedict, 11-12, 1916.

Preparation of oxygen from silver oxide

Preparation of oxygen from silver oxide

Preparation of oxygen from silver oxide

Another compound of oxygen that is easily decomposed by heat is silver oxide. The decomposition is attended by a characteristic change in color from the brown of the oxide to the silver-white of the metal.

Chemical lecture experiments, by F. G. Benedict, 11-12, 1916.

Preparation of oxygen from mercury oxide

Preparation of oxygen from mercury oxide

Preparation of oxygen from mercury oxide

A one-centimeter layer of dry mercuric oxide is placed in a hard-glass test-tube, and heated with a Bunsen burner. The tube is clamped in an inclined position nearly horizontal, and the burner with its chimney so arranged that only the mercuric oxide is heated, that portion of the test-tube above the oxide remaining as cool as possible.

A glass apparatus for the preparation of oxygen from mercury oxide

A glass apparatus for the preparation of oxygen from mercury oxide

By using a somewhat larger portion of mercuric oxide, and fitting a cork with a delivery-tube into the mouth of the test-tube, sufficient oxygen may be obtained.

Chemical lecture experiments, by F. G. Benedict, 8-9, 1916.

Preparation of oxygen by electrolysis of copper sulfate solution

Preparation of oxygen by electrolysis of copper sulfate solution

Preparation of oxygen by electrolysis of copper sulfate solution

In the electrolysis of copper sulfate, where but one of the final products of electrical decomposition is gaseous, that product, oxygen, The glass bottle of the electrolytic apparatus is completely filled with a saturated solution of copper sulfate, and the cork inserted in such a manner as to drive out all the air and fill the delivery tube with the solution.

A glass apparatus for the preparation of oxygen by electrolysis of copper sulfate solution

A glass apparatus for the preparation of oxygen by electrolysis of copper sulfate solution

If a current from battery is passed through the apparatus, a steady stream of oxygen will be delivered. One of the platinum electrodes, the negative one, will become coated almost instantly with metallic copper; the other, from which the bubbles of gas rise, will retain its original color.

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