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In this coursework, I aim to find out the different properties of gold and alloying and will analyse pieces of data pertaining to gold in particular

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Introduction

Chemistry Coursework Gold and Alloying Introduction In this coursework, I aim to find out the different properties of gold and alloying and will analyse pieces of data pertaining to gold in particular; I will also be discussing the reasons as to why alloying is done and, finally, I will be providing evidence in the light of science and ethics in favour of and against alloying. Properties of Gold and Alloys Gold has for centuries been regarded as a prized possession; it has been used world wide for various purposes, from the treasures of the Ancient Egyptians to the manufacture of computer chips. Gold has an atomic number of 79 and is among the transition metals. There are different types of gold, determined on its purity. The carat system is often used to resolve the purity of gold. 24 carat gold is regarded as the most pure type of gold, which occurs naturally as very dense, soft, shiny and the most malleable and ductile pure metal known. 24 carat gold (pure gold) has a rich yellow colour as opposed to impure gold. The chemical factors which gold possesses makes it an excellent metal to be used for many things. It is extremely unreactive, which makes it a brilliant metal to be used for jewellery because it does not tarnish as a result of reacting with oxygen. ...read more.

Middle

and 18 carat (white) is that the latter contains palladium; like nickel, it may be the cause for the difference in colour between the alloys. Also, after reviewing the density of the both alloys in Table 1, it is clear that 18 carat (white) is significantly denser than that of 18 carat (yellow). Again, this could be because 18 carat (white) contains an extra element, palladium, so the reason for the difference in density could be linked with the fact that one contains palladium whereas the other does not. These differences suggest that nickel and palladium are the substances added to gold in order to whiten it. Another trend which I have found is that the alloys which appear yellow in colour contain a greater amount of copper than their white counterparts; for example, 9 carat (yellow) contains 5% more copper than 9 carat (white) and 14 carat (yellow) contains 4.2% more than 14 carat (white). So the factor for the difference between the colours could be due to the amount of copper. Validity and Reliability For my investigation I extracted data from the source www.24carat.co.uk . In order to make the data valid, I made sure I used data only from this source and not any other source. This meant that my comparison between the data which I had collated would be more accurate and valid than if I were to take data from a variety of sources and then compared them. ...read more.

Conclusion

consume huge amounts of energy; annealing involves subjecting the metal to just above re-crystallisation temperature, which emits large amounts of greenhouse gases as a result of burning fossil fuels. Manufacturing pure gold does not release as much atmospheric pollution as manufacturing gold alloys. Gold alloys are sometimes used in tooth fillings; the problem with these is that it gives an unnatural tooth colour, so a lot of dental patients prefer to have them removed and do not like having these fillings. Finally, alloying is not entirely cost effective; for example, palladium is a very expensive and also heavy metal, thus jewellery made in palladium white metals tend to be more expensive than nickel whites. Also, elements which are used to whiten gold, such as chromium and iron, are usually hard and very hard to process and purify before they can successfully be alloyed with gold. Gold alloys also tend to be more brittle, so a sharp blow would most probably cause it to disintegrate. Conclusion Gold alloys have a number of advantages along with disadvantages; the way to decide whether it is more advantageous than pure gold is to see whether the benefits outweighs its drawbacks; gold alloys are stronger, lighter, cheaper and more effective, as they offer a wider range of usage than pure gold, which is naturally too soft and weak to meet the demands for gold in modern times. ?? ?? ?? ?? 2 ...read more.

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