Chemistry Project On Coin Analysis

Transcription

1 1 Chemistry Project On Coin Analysis

2 2 AIM Qualitative Analysis Of Different Coins

3 3 CERTIFICATE This is hereby to certify that, the original and genuine investigation work has been carried out to investigate about the subject matter and the related data collection and investigation has been completed solely, sincerely and satisfactorily regarding her project titled Qualitative Analysis of Coins. Teacher s Signature

4 4 ACKNOWLEDGEMENT It would be my utmost pleasure to express my sincere thanks to My Chemistry Teacher Mrs./Mr., in providing a helping hand in this project. Her valuable guidance, support and supervision all through this project titled Qualitative Analysis of Coins, is responsible for attaining its present form.

5 5 PURPOSE I was interested in finding out the contents of the coins we use in everyday life money transactions. Humans have been using coins since their invention in 700 B.C. for trading of goods and services. Another fact which inspired me to do this project is that I am in touch with qualitative analysis whose knowledge with other factors helped me to do so.

6 6 CONTENTS Introduction Theory Apparatus Chemicals Required 20 Paise Coin (India) 1 Cent Coin (U.S.A) 2 Rupee Coin (India) 1 Rupee Coin (India) Result Conclusion

7 7 INTRODUCTION An alloy is a mixture or metallic solid solution composed of two or more elements. Complete solid solution alloys give single solid phase-microstructure. Alloys usually have different properties from those of the component elements. Alloying a metal is done by combining it with one or more other metals or non-metals that often enhance its properties.alloys are used in ornaments, bells, statues, buildings, and even coins. Coins-A Historical Approach The history of coins extends from ancient times to the present, and is related to economic history, the history of minting technologies, and the history of coin collecting. Coins are still widely used for monetary and other purposes. Since the time they were invented in 700 B.C., coins have been the most universal embodiment of money.

8 8 The first coins were made of electrum, a naturally occurring pale yellow mixture of gold and silver that was further alloyed with silver and copper. Some of the earliest coins were beaten at the edges to imitate the shape of a cow, in indication of their value. Most coins are circular but some were rectangular. Also a lot of coins, especially in China had a hole through the center so they could be tied on to a string.some of the earliest coins to be made purely from silver and gold were the silver Dirham and gold Dinar. Coins were first made of scraps of metal. Ancient coins were produced through a process of hitting a hammer positioned over an anvil.the Chinese produced primarily cast coinage, and this spread to South-East Asia and Japan. The type of mintage method (being hammered, milled or cast) does limit the materials which can be used for the coin. For example antimony coins, (which are very rare) are nearly always cast examples, because of the brittle nature of the metal, and thus it would break if

9 9 deformed, which is a key part of the milling or hammering process. Coins today are of great value and are used in our dayto-day lives.

10 10 THEORY A coin is a piece of hard material that is standardized in weight, is produced in large quantities in order to facilitate trade, and primarily can be used as a legal tender token for commerce in the designated country, region, or territory. Coins are usually metal or a metallic material and sometimes made of synthetic materials, usually in the shape of a disc, and most often issued by a government. Coins are used as a form of money in transactions of various kinds, from the everyday circulation coins to the storage of large numbers of bullion coins. In the present day, coins and banknotes make up currency, the cash forms of all modern money systems. An alloy is a homogeneous mixture of two or more metals or a metal and non-metal. They are generally harder than their components with reduced malleability and ductility. Alloys are prepared

11 11 to enhance certain characteristics of the constituent metals, as per requirement. The coinage metals comprise, at minimum, those metallic chemical elements which have historically been used as components in alloys used to mint coins. Coins that are intended for circulation have some special requirements based on the conditions they will encounter. For example, a coin may be in circulation for up to 30 years, and so must have excellent wear resistance and anti-corrosion properties. Achieving this goal necessitates the use of base metal alloys. Some metals like manganese have occasionally been used in coins, but suffer from making the coins too hard to take an impression well. A common base metal alloy for everyday coinage is Cupro-Nickel (also cupronickel), with varying proportions of copper and nickel, most commonly 75% Cu 25% Ni. Cupronickel has a silver color, is hard wearing and has excellent striking properties, essential for the design of the coin to be pressed accurately and quickly during manufacture.

12 12 APPARATUS Test Tubes Test Tube Holder Test Tube Stand Beaker Burner Tripod Stand ph Paper Wire Gauge Water Bath Filter Paper

13 13 CHEMICALS REQUIRED Hydrochloric Acid (HCl) Sodium Hydroxide Hydrogen Sulphide Gas Nitric Acid (HNO3) Ammonium Acetate Potassium Iodide Potassium Chromate Potassium Ferrocyanide Ammonium Hydroxide Ammonium Chloride Potassium Sulphocyanide Potassium Nitrite Ammonium Thiocyanide Dimethyl Glyoxime Bromine Water Ammonium Carbonate Ammonium Phosphate

14 14 Twenty Paise Coin (India)-Made in 2003 Experiment Observation Inference Zero Group: Add concentrated solution of sodium hydroxide(naoh) to it. Group I: Add dilute solution of hydrochloric acid to the original solution. Group II: Add dilute solution of HCl to the original solution and pass H2S gas through it. Group III: Add NH4Cl and NH4OH(in excess) to the original solution. No white fumes observed. No white precipitate formed. No black or yellow precipitate formed. A white precipitate is Ammonia (NH4 +) is Pb 2+, Ag 2+ and Hg2 2+ are Pb 2+, Cu 2+,As 3+ are Al 3+ may be present.

15 15 Confirmatory For Cl 3+ : Lake Test: Dissolve the white precipitate obtained int dilute HCl. Add to it two drops of blue litmus solution. To this, add NH4OH drop wise till blue colour develops. Blue precipitate is observed floating in the colourless solution. Al 3+ is present. Group IV: Use the same solution as used in Group III tests and pass H2S gas through it. No precipitate formed. Co 2+,Ni 2+,Mn 2+ and Zn 2+ are Group V: To the original solution, add NH4Cl, NH4OH and (NH4)2CO3. Group VI: To the original solution, add NH4Cl, NH4OH (in excess) and (NH4)2HPO4. No white precipitate formed. A white precipitate is Ba 2+, Ca 2+ and Sr 2+ are Mg 2+ may be present.

16 16 RESULT Twenty Paise Coin of India contains Aluminium(Al 3+ )and Magnesium(Mg 2+ ).

17 17 One Cent Coin (U.S.A)-Made in 1987 Experiment Observation Inference Zero Group: Add concentrated solution of sodium hydroxide(naoh) to it. No white fumes observed. Ammonia (NH4 +) is Group I: Add dilute solution of hydrochloric acid to the original solution. No white precipitate formed. Pb 2+, Ag 2+ and Hg2 2+ are Group II: Add dilute solution of HCl to the original solution and pass H2S gas through it. A black precipitate Cu 2+ may be present. Confirmatory for Cu 2+ : Heat the black precipitate with 1-2 ml of 50% HNO3.The precipitate dissolves and add dilute H2SO4 and alcohol. Blue coloured solution Cu 2+ may be present.

18 18 When there is no white precipitate,add NH4OH in excess. Potassium ferrocyanide test: To one part of the blue solution add acetic acid and potassium ferrocyanide solution. Potassium Iodide test: To another part add acetic acid and potassium iodide solution. A chocolate brown precipitate is A white precipitate is formed in the brown coloured solution. Cu 2+ is present. Cu 2+ is present. Group III: Add NH4Cl and NH4OH(in excess) to the original solution. A white precipitate is Al 3+,Cr 3+,Fe 3+,Fe 2+ are Group IV: Use the same solution as used in Group III tests and pass H2S gas through it. A dull white precipitate is Zn 2+ may be present.

19 19 Confirmatory for Zn 2+ : Sodium hydroxide test: To one part of the original solution add sodium hydroxide solution drop-wise. A white precipitate is Add more NaOH to dissolve the precipitate. Zn 2+ is present. Potassium ferrocyanide test: To another part, add potassium ferrocyanide solution. A white or bluish white Zn 2+ is present. precipitate. RESULT Twenty Paise Coin of India contains Zinc (Zn2+) and Copper (Cu2+).

20 20 Two Rupees Coin (India)-Made in 2003 Experiment Observation Inference Zero Group: Add concentrated solution of sodium hydroxide(naoh) to it. Group I: Add dilute solution of hydrochloric acid to the original solution. No white fumes observed. No white precipitate formed. Ammonia(NH4 +) is Pb 2+, Ag 2+ and Hg2 2+ are Group II: Add dilute solution of HCl to the original solution and pass H2S gas through it. A black precipitate Cu 2+ may be present. Confirmatory for Cu 2+ : Heat the black precipitate with 1-2 ml of 50% HNO3.The precipitate dissolves and add dilute H2SO4 and alcohol. Blue coloured solution Cu 2+ may be present.

21 21 When there is no white precipitate,add NH4OH in excess. Potassium ferrocyanide test: To one part of the blue solution add acetic acid and potassium ferrocyanide solution. Potassium Iodide test: To another part add acetic acid and potassium iodide solution. A chocolate brown precipitate is A white precipitate is formed in the brown coloured solution. Cu 2+ is present. Cu 2+ is present. Group III: Add NH4Cl and NH4OH(in excess) to the original solution. Group IV: Use the same solution as used in Group III tests and pass H2S gas through it. A white precipitate is A black precipitate is Al 3+, Cr 3+, Fe 3+, Fe 2+ are Ni 2+ may be present.(if the original solution is green).

22 22 Confirmatory for Ni 2+ : Dimethyl glyoxime test: To one part of the original solution add ammonium hydroxide solution and few drops of dimethyl glyoxime. A bright rose red precipitate is Ni 2+ is present. Sodium hydroxide - bromine water test: To another part add sodium hydroxide (in excess) and bromine water and boil. A black precipitate is Ni 2+ is present. RESULT Two Rupee Coin of India contains Copper (Cu 2+ ) and Nickel (Ni 2+ ).

23 23 One Rupee Coin (India)-Made in 2010 Experiment Observation Inference Zero Group: Add concentrated solution of sodium hydroxide(naoh) to it. Group I: Add dilute solution of hydrochloric acid to the original solution. No white fumes observed. No white precipitate formed. Ammonia(NH4 +) is Pb 2+,Ag 2+ and Hg2 2+ are Group II: Add dilute solution of HCl to the original solution and pass H2S gas through it. Group III: Add NH4Cl and NH4OH(in excess) to the original solution. No black or yellow precipitate formed. A reddish brown precipitate is Pb 2+, Cu 2+, As 3+ are Fe 3+ may be present. Confirmatory for Fe 3+ : Dissolve the reddish brown precipitate in dilute

24 24 HCl, and divide the solution into two parts. Potassium ferrocyanide test: Prussian Blue To one part of the above colouration is solution add potassium ferrocyanide solution. Fe 3+ is present. Potassium sulphocyanide test: To the second part, add a little potassium sulphocyanide solution. Blood red colouration is Fe 3+ is present. RESULT Two Rupee Coin of India contains Iron (Fe 3+ ).

25 25 RESULT Amount Country Year Ions present Twenty Paise Coin India 1938 Al 3+ and Mg 2+ ions One Cent Coin U.S.A 1987 Cu 2 + and Zn 2+ ions Two Rupee Coin India 2003 Cu 2+ and Ni 2+ ions Fe 3 One Rupee coin India ion

26 26 BIBLIOGRAPHY LABORATORY MANUAL OF CHEMISTRY WEBSITES