Silver pennies

If you had lived in earlier times in the United States, you might have bought a horse or a house with 10 coins made of gold. You may still have some old dimes, quarters, and dollars made of silver. Copper pennies, of course, are an everyday sight. These three transition elements have been used as money since ancient times in almost all parts of the world. 

Figure 23. Cost of sterling silver and of pure gold vs. time, expressed in English pennies per troy ounce, a.d. 1000-1950.

Copper, being easy to mine and refine, has become a very versatile metal over the course of civilization. Early in human history, it was discovered that soft copper could be made harder and stronger when alloyed with other metals. Copper was and still is important to technology and the development of civilizations. Over the past several thousand years, brass has found multiple uses, such as in coins, cooking utensils, and many types of instruments and hardware that are resistant to corrosion. Even today, brass is used to make musical instruments and bathroom, kitchen, and marine hardware. The U.S. one-cent penny was originally made of copper, but today the penny is made of zinc with a coating of copper. Copper is also an alloy metal used as a substitute for some of the silver in several other U.S. coins. 

Silver-colored coins do not have to be transformed into gold coins immediately. The coins can be plated with zinc and saved for heating at a later time. Excess lye solution can be poured down the drain after diluting with plenty of cold water. Plate enough pennies until the zinc is used. Old pennies can be plated, but will produce a duller, dirty finish. 

The silver color is due to the plating of zinc on the penny. The final heating process causes the copper and zinc to fuse, producing a brass alloy. Brass is an alloy of zinc and copper. Typical brass alloys contain between 3% and 30% zinc. 

Lykiardopoulou-Petrou M, Beloyannis N (1998) Experimental comparative study of three different cleaning processes on Athenian silver coins (tetradrachms) from classical times . In Look After the Pennies, Goodburn-Brown D and Jones J (Eds), Archetype Books, London, 85-88. 

The silver chlorine ratio was determined by E. Turner (1829),4 F. Penny (1839), J. C. G. de Marignac (1842), J. B. A. Dumas (1860), J. S. Stas (1865), and by T. W. Richards and R. C. Wells (1905) by the precipitation of silver chloride. L. Maumene reduced silver chloride to the metal by heating it in a stream of hydrogen and J. S. Stas also synthesized silver chloride by heating the metal in chlorine gas. This ratio has also been determined by several less direct methods. F. W. Clarke s calculations furnished 32 8606 0 00031 for the general mean representing the amount of chlorine which combines with 100 parts of silver to form silver chloride. 

The values obtained by Stas for the atomic weights of silver, chlorine, and bromine were 107-930, 35-457, and 79-952, and were employed for many years. By their aid the atomic weight of sodium can be calculated from the results already cited. From Penny s experiments (NaC103 30) it follows that NaCl =58-500. From the mean ratio Ag NaCl it can be calculated that NaCl =58-506. The average result is NaCl=58-503. From the ratio Ag NaBr it follows that NaBr=... 

MAKING YOUR PENNIES MORE VALUABLE TURNING COPPER INTO SILVER AND GOLD Procedure ... 

A gentle warming of the solution on a hot plate is necessary for the pennies to take on a silver color.The pennies can be turned over and the warming continued until a uniform silver color is achieved. Remove the pennies and rinse them with distilled water. You will notice that you have turned your old copper penny into a silver penny. By carefully heating the penny in a Bunsen burner or on a hot plate, the penny will become a beautiful gold color.The mixture of copper and zinc that you have made is actually a brass alloy and not gold I... 

Experiments, such as qualitative analysis of ions via precipitation with a cation or anion [3], the isolation of banana (or strawberry) DNA [4], creating a DNA alias [5], coagulation of milk [6], examining reactions for exothermic or endothermic properties [7], follens test for aldehydes [8] and the conversion of copper pennies to silver [9] have been completed by the participating students. 

The comparison of approximately one mole each of silver (as Morgan and Peace dollars), gold (as Canadian Maple Leaf coins), and copper (as pennies) shows the considerable difference in mass (as well as economic value) of equivalent moles of different substances. 

One of the most important uses of silver has hitherto been for coins. Silver pennies were used by our Saxon ancestors. Standard... 

The solution of silver in nitric acid, and the evaporations of the salts with the acids, were made in a horizontal weighed round-bottomed flask heated on a sand bath, with the neck passing inside another flask. He used an empty flask counterpoise as a gauge flask . Penny s results have not been recalculated recently with a correct atomic weight of silver and reduction of the weights to a vacuum, but his value for nitrogen (14 026) found from the conversion of the sodium salts is rather better than Stas s (14 04). Penny also introduced the titration of ferrous iron with potassium chromate or dichromate, using potassium ferricyanide as external indicator. 

The diameter of a U.S. penny is 19 mm. The diameter of a silver atom, by comparison, is only 2.88 A. How many silver atoms could be arranged side by side in a straight line across the diameter of a penny ... 

Solution The unknown is the number of silver (Ag) atoms. We use the relationship 1 Ag atom = 2.88 A as a conversion factor relating the number of atoms and distance. Thus, we can start with the diameter of the penny, first converting this distance into angstroms and then using the diameter of the Ag atom to convert distance to the number of Ag atoms ... 

That is, 66 miUion silver atoms could sit side by side across a penny ... 

Figure 2.17 Common elements and compounds, (a) Familiar objects that are nearly pure elements copper wire and the copper coating on pennies iron nuts and bolts coated with zinc for corrosion protection lead sinkers used for fishing graphite, a form of carbon, which is the lead in lead pencils aluminum in a compact disc pieces of silicon, used in the computer chips shown next to them and silver in bracelets, (b) Familiar substances that are compounds drain cleaner, sodium hydroxide (made up of the... 

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