Transcript Shaun Lynn Aux

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
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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/