Man's physical universe

xanabras

ELECTRON TRANSFER 599

Magnesium is a competitor of aluminum. Magnesium is a lighter

metal than aluminum, and its alloys are very strong.

A new process has been developed for the production of magnesium

from magnesite (magnesium carbonate), a very abundant rock, by

reduction with coke in an electric furnace. This promises to make

magnesium available at half the price of aluminum. Dow metal contains

90 per cent or more of magnesium, plus 10 per cent or less of

aluminum, plus small amounts of other metals. Its use in airplane

construction is well known.

Only a few hundred pounds of cadmium were produced in 1890,

but the world production in 1940 was 12,000,000 pounds. Cadmium

is replacing zinc for many purposes because it produces a protective

coating on iron which is superior to it under some circumstances.

Electrolysis is being used increasingly in the organic chemical industry

to oxidize and reduce organic compounds. The advantage of

electrolytic oxidation and reduction is that it can be carried out at

ordinary temperatures and pressures and can be accurately controlled.

The melting-point of beryllium is 1285° C, 185° above the meltingpoint

of copper. A very little beryllium added to gold makes the gold

very hard. Two per cent of beryllium added to copper gives it the

strength of steel, in fact, a beryllium-copper chisel may be hammered

through soft steel. Two per cent of beryllium added to nickel gives it

a tensile strength after heat treatment of 260,000 pounds per square

inch, as compared with only 60,000 pounds per square inch for structural

steel. From 0.01 to 0.02 per cent of beryllium imparts a smooth

grain to copper castings and improves the electrical

conductivity of

copper as much as 20 per cent and at the same time makes the copper

more resistant to corrosion. From 1 to 5 per cent of beryllium in silver

prevents it from tarnishing with sulfur and sulfur compounds.

Only those metals which are below hydrogen in the displacement

series can be prepared by electrolysis of their water solutions. All

metals above hydrogen in the displacement series, such as sodium,

magnesium, aluminum, and beryllium, are prepared by the electrolysis

of their melted compounds.

A very interesting recent development is an electrolytic method of

producing a high polish of mirror-like quality on steel, nickel, copper,

brass, and zinc that protects them against corrosion.

STUDY QUESTIONS

1. Which type of elements loses electrons most readily?

2. What are the two main types of chemical reactions?

3. Give examples of each of the four main types of electron transfer.

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