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Scientific Skills Gold Shaun Lynn J9106574 Occurrence & Extraction of Gold Gold has an abundance of 4ppb of the Earth’s crust Also found alloyed to other metals such as silver Occurrence & Extraction of Gold Nuggets Grains Microscopic 2/3 world’s output . Purification of Gold Smelting Cyanidation 4Au + 8NaCN +O2 +H2O 4[NaAu(CN)2] +4H2O Reaction With Air & Water • Chemically unreactive • Does not react with air or with water Electron configuration is [Xe] 4f14 5d10 6s1 D orbital is saturated chemical unreactivity Crystal lattice structure is face centred cubic Surface structure with limited freedom for bonding Good for adsorption Reaction With Acids Also unaffected by acids and bases Except: Aqua Regia (3:1 mixture of hydrochloric & nitric acid) Reaction With Acids • Gold + Aqua Regia Au (s) + 3 NO3- (aq) + 6 H+ (aq) → Au3+ (aq) + 3 NO2 (g) + 3 H2O (l) • This could be taken one step further to make chloroauric acid (liquid gold) Au3+ (aq) + 4 Cl- (aq) → AuCl4- (aq) Oxidation States • Gold has an oxidation state of +1 and +3 • However, it has the ability to reach a maximum oxidation number of +5 Oxidation States • In an atmosphere of oxygen and fluorine, at 400°C at 8 atmospheres: 2 Au + 2 O2 + 6 F2 → 2 O2AuF6 2 gold dioxyflouride salt • This will decompose at 180°C : O2AuF6 → Au2F10 + 2 O2 + F2 Octahedral with Bi dentate fluoride bonds Gold(v) pentafluoride Uses Catalyst •Heterogeneous •Catalytic Converter •Adsorbs O2 and CO and allow CO2 to form. Uses As a catalyst: • Remove bad smells and toxins from the atmosphere • Glucose to Gluconic acid • Vinyl acetate monomers In medicine: • Used to treat arthritis since 1929 • Prostate cancer treatment Also: • Fine Jewellery • Currency is dependent upon gold Interesting Compound! • Gold also has an oxidation state of -1 to form an Au-1 anion • This enables gold to react with metals with an oxidation state of +1, to form ionic compounds with non metalic properties. E.g. • CsAu Cesium Auride has a low melting point of 480°C classified as a semi conductor References • • • • • • • • • Chloroauric Acid (Liquid gold) : Molecule of the Day. (2010, March 01). Retrieved march 01, 2010, from Science Bloggs: http://scienceblogs.com/moleculeoftheday/2007/08/chloroauric_acid_liquid_gold.php Nobel Foundation. (2010, March 01). The Nobel Prize Medals and the Medal for the Prize in Economics. Retrieved March 01, 2010, from nobelprize.org: http://nobelprize.org/nobel_prizes/medals/ Unknown. (2010, February 26). Gold element facts. Retrieved February 26, 2019, from Chemicool: http://www.chemicool.com/elements/gold.html Unknown. (2010, February 2010). Gold Elements Facts. Retrieved february 28, 2010, from Chemicool: http://www.chemicool.com/elements/gold.html Walker, J. (2010, march 08). What Gives Gold that Mellow Glow? Retrieved March 08, 2010, from Fourmilab Switzerland: http://www.fourmilab.ch/documents/golden_glow/ Winter, M. (2010, February 28). Table of the Elements | Gold | chemical reaction data. Retrieved February 28, 2010, from WebElements : http://www.webelements.com/gold/chemistry.html Housecroft, C. E. (2006). Chemistry An introduction to Organic, Inorganic and Physical Chemistry (Third Edition ed.). harlow, Essex, England: Pearson Education Limited. World Gold Council. (n.d.). Properties. Retrieved march 07, 2010, from World Gold Council: http://www.utilisegold.com/uses_applications/properties_of_gold/ World Gold Council. (n.d.). Uses and applications. Retrieved march 07, 2010, from World Gold Council: http://www.utilisegold.com/uses_applications/properties_of_gold/