Reactivity Series And Redoz Flashcards
What are easiest metals to extract
The least reactive metals like gold beacsue they can be found as native metals and occur naturally as their metal
How do you extract moderately reactive metals
Metals below carbon can be extracted cheaply and easily by heating their ores with carbon to bring about a displacement reaction. These metals are not found native because they combine with oxygen or moisture in the air to from compounds
How do you extract metals more reactive than carbon
By electrolysis
What are the three raw materials fed into the top of the blast furnace
Iron ore , coke , limestone and blast of hot air
What does the coke do
Burnis in hot air to form carbon dioxidE. This reaction is very exothermic and provides the high temperatures needed for the furnace to function . Higher up in the furnace carbon dioxide reacts with more coke to form carbon monoxide
What does the carbon monoxide do
Reacts with iron oxide ( haematite) to form carbon dioxide and molten iron which collects at the base of the furnace where it can be tapped off .
What does the calcium carbonate do
Thermally decomposes to form calcium oxide and carbon dioxide . Calcium oxide reacts with silicon dioxide impurities to make calcium silicate which forms slag that floats on top of the molten iron and can be tapped off seperately and used for road surfacing and cement making
How is steel made
Most of carbon is removed from the pig iron making it stronger than cast iron and it’s used for construction . This is done by basic oxygen process , oxygen gas is bubbled through molten pig iron making most of the carbon present burn off as carbon dioxide gas leaving mild steel . Calcium oxide is also added to take away impurities . Other metals can be addressed to make stainless steel which is very resistant to corrosion so is therefore used for cutlery
Cast iron
Iron from the blast furnace impure , very hard but brittle used for guttering . Wrought iron is pure iron and used for decoration
High carbon steel
Makes steel harder but more brittle so used for cutting tools
Reduction
Gain of electrons loss of oxygen
Oxidation
Gain of oxygen loss of electrons
Why aluminium dissolved in cryolite
Needs to be molten to conduct electricity , cryolite has a lower melting point than aluminium making electrolysis cheaper and easier
What is the cathode for electrolysis of aluminium
Graphite lining of electrolysis cell . Molten aluminium sinks to bottom of cell on cathode and can be talked off
What are the anodes for electrolysis of aluminium
Graphite anodes dipped into electrolyte . Oxygen glass forms here and is hot so it causes the electrodes to burn away making it expensive as they have to be replaced
How do you extract zinc
Roast zinc sulphide in air to give zinc oxide
- React it with sulphuric oxide to give zinc sulphate then electrolyse using l ad anode and aluminium cathode
Or - thermal extraction mic zinc oxide with coke and displace lent reaction will occur forming carbon monoxide zinc
Carbon monoxide removes oxygen from zinc oxide to give zinc and carbon dioxide
What is nickel
Corrosion resistant
What is rusting
Redox reaction , iron atoms in the metal loose electrons to form iron 3 ions in the rust iron oxide. The oxygen with it reacts is reduced and gains these electrons
How do you prevent rusting
- Barriers e.g. Painting
2.alloying this iron - Use sacrificial metals , galvanised iron is iron coated with a layer of zinc which is more reactive than iron so it corrodes instead of the iron
Zinc looses electrons to from zinc ions
Reactivity series
Postassium sodium lithium calcium magnésium aluminium carbon zinc iron hydrogen copper
What colour does iron turn when oxidised
Colourless to yellow
Colour change iodide
Colourless to brown
Colour change bromine
Colourless to orange
Rust chemichal name
Hydrated iron oxide
