From Stone to Mystic Metal

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From Stone to Mystic Metal A journey of discovery

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Transcript of From Stone to Mystic Metal

Page 1: From Stone to Mystic Metal

From Stone to Mystic Metal

A journey of discovery

Page 2: From Stone to Mystic Metal

Before metals

• Pre 9000 BCE - Stone Age

• Malachite (a green copper ore) and Hematite (a red iron ore) ground to powder and used for art work

• Coloured ores used as jewellery

• All tools made from stone and wood

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Discovery of metals

• Earliest known metals were “native”metals

• Found as nuggets

• Copper, silver, gold

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Ores

• Compared to pure metals, ores were just rocks

• No ‘metallic splendour’

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Native Metals vs OresNative metal Ore

Lustre (Shiny) Some are glittery

Malleable (can be hammered into sheets) Shatter when hit by a

hammerDuctile (can be drawn into wires)

Conduct electricity and heat Don’t conduct electricity and heat

Insoluble Insoluble

Don’t burn Don’t burn

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Native metals could be....

• Converted to a state similar to ores by heating with sulphur

• Earliest forms of ores (metal sulphides)

• Formed naturally by heat and sulphur from volcanic activity

• This can also be done by heating in air (oxygen)

• This form of ore (metal oxides) developed naturally after plant life formed on Earth.

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Timeline

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Major Discovery!

• Ores can be converted to metal by heating with charcoal

• Discovered by accident?

• Copper bearing rocks around a camp fire

• Inefficient method but...

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Copper Smelting• Development of a simple clay kiln plus use of

bellows - much more efficient due to increased temperature

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Copper smelting

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Progress

• Without the discovery of the smelting process...

• No extraction of other “non-native” metals such as tin or iron

• No Bronze or Iron Ages (and no further progress!)

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The Thermite reaction

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Alloys

• A mixture of metals

• Have different properties to the metals that make them up

• Bronze - a mixture of copper and tin

• Brass - a mixture of copper and zinc

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Reactivity seriesA list showing metals in order of their reactivity

(from most to least)

• Magnesium

• Aluminium

• Zinc

• Iron

• Lead

• Copper

Note: This list is a partial list

Going from bottom to top, the metals:

• increase in reactivity;

• lose electrons more readily to

form positive ions;

• corrode or tarnish more

readily;

• require more energy (and

different methods) to be

separated from their ores

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Metal Reactivity ExtractionPotassium K

React with waterElectrolysis

Sodium Na

Lithium Li

Strontium Sr

Calcium Ca

Magnesium Mg

React with acids

Aluminium Al

Zinc Zn

Smelting with coke

Chromium Cr

Iron Fe

Cadmium Cd

Cobalt Co

Nickel Ni

Tin Sn

Lead Pb

Copper Cu

Highly unreactiveHeat or physical

extraction

Silver Ag

Mercury Hg

Gold Au

Platinum Pt

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Transition Metals

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Transition Metals•Cobalt - Pink

•Manganese - Orange

•Copper/Nickel - Blue or Greenish Blue

•Iron - pale Green or Red

•Titanium/Zinc- White

•Vanadium - Yellow

•Chromium - Yellow/Red

•Note all bunched together in terms of weight

•All the coloured salts are multi-valency

•Valency = the number of bonds an atom will form with another element