ELECTROLYSIS OF WATER

The electrolyte is water to which is added a little acid, base or salt for better conductivity. When a current is passed through the cell, gas bubbles are produced at the electrodes A and K. If the electrodes are covered by test tubes, the gas bubbles will rise, displacing the water. The test tube over the cathode K will be filled twice as fast as the one over the anode A. If the left-hand test tube is lifted and a burning match applied to its mouth, the gas in the tube will burn giving bluish flame and popping sound. This gas is hydrogen.

If a smouldering wooden stick is inserted into the test tube over the anode, the stick will flare up with a bright flame. This is an indication that the gas in the tube is oxygen. The above experiment is used in chemistry to prove that water consists of two gases – oxygen and hydrogen.

G. Write down all physical and chemical terms, known to you from above studied

exercises in English.

H. Translate the sentences from English into Russian, use your new word stock and

Grammar, underline the verbs and define their Tense and Voice.

1. The first law of Faraday is expressed as follows: the amount of chemical change

(or of substance) produced at the electrodes in an electrolytic cell is directly proportional to the quantity of electricity passing through the electrolyte.

1. The weight of an element or a group of elements free by the passage of one coulomb of

electricity ( one ampere / one second ) is called the electro-chemical equivalent of that element or group.

1. Faraday’s second law can be started as follows: the amount of various substances

liberated at the electrodes by the same quantity of electricity is directly proportional to their chemical equivalent weights.

1. Faraday’s second law establishes the relationship between the electrochemical and

chemical equivalents of substances.

1. The industrial applications of electrolysis are wide: electroplating, electroforming,

electrolytic refining of metals, electrolytic reduction of metals.

1. Aluminium is produced from bauxite.
2. The ore contains silica (silicon oxide) and iron oxide.
3. As the electrolytic process requires large blocks of electric power, it is customary to build aluminium factories near big hydro-electric stations.
4. Electrical uses for aluminium include wires, cables, line hardware.
5. The ore is ground and roasted in suitable furnaces to eliminate the iron, sulphur, arcenic, antimony, bismuth, lead, phosphorus and other impurities present in the ore.

I .Translate the words in brackets from Russian into English and be ready to retell

the text.

Date: 2014-12-28; view: 920