Karteikarten
Metals and their extraction
Karten in diesem Stapel (19)
- 1What is the source of most metals?Ores (bauxite=iron, haematite=aluminium) reacted with other elements in forms of rock.
Native metals (gold) very unreactive so found as elements. - 2Describe the impact of reactivity on ease of extraction.Below carbon on reactivity series = displaced with carbon (cheaper than using other more reactive metals)
Above carbon = electrolysis (cheaper than using another more reactive metal to displace) (economically viable)
More attractive = more reactive - 3Use displacement reactions to demonstrate the reactivity of metals.Mg + CuSO4 -----> Cu + MgSO4
Magnesium + copper sulphate ---> copper + magnesium sulphate - 4Define the term 'reduction'.The removal of oxygen atoms from a substance via a chemical reaction.
The gain of electrons. - 5Define the term 'Oxidisation'.The addition of oxygen to a substance via a chemical reaction.
The loss of electrons. - 6Explain (in detail) how iron is extracted in industry.
- 7Uses of the following: Limestone Hot air Coke SlagIron ore – (usually haematite) Mainly iron mixed with sand, FE2O3.
Limestone – Common rock consisting mainly of calcium carbonate, CaCO3. Removes acidic impurities from the iron by reacting with them to form molten slag.
Hot air – Blasted into bottom of furnace to provide heat and oxygen.
Coke – Is made from coal. Is nearly pure carbon. Acts as fuel.
Slag – Used to pave roads. A - 8What are some sustainability issues with the extraction of metals from their ores?* Contamination of land - environmental impact
* Fuel and energy costs
* Pollution/greenhouse gas emissions - 9Outline the industrial extraction of aluminium.* Aluminium high in reactivity series
* Electrolysis is used because aluminium more reactive than carbon
* electricity = cheaper than using more reactive metals.
* Molten electrolyte needed to enable electrons to move freely.
* Electrolysis expensive still due to amount of electricity needed.
* Cryolite added to reduce melting point = less energy needed.
* Al3+ ions attracted to cathode
* O2- attracted to anode.
Cathode: Al3+ + 3e− → Al
Anode: 2O2− → O2 + 4e− - 10Describe in detail how electrolysis is used to extract metals from molten ionic compounds.Chloride ions change into chloride gas as they give up electrons to the anode:
2CL-(L) -----> Cl2(G) +2e-
Zinc ions are changed into zinc atoms as they gain electrons from the cathode:
Zn2+(L) + 2e- ---> Zn(S) - 11Properties and uses of steel:Tough, malleable, poor resistance to corrosion
Construction of roads, bridges. - 12Properties and uses of aluminium:Lightwieght, resist corrosion, malleable.
Aeroplane wings, cans. - 13Properties and uses of copper:good electrical conductivity.
good thermal conductivity.
corrosion resistance
Electrical wiring in TVs, pans. - 14Properties and uses of titanium:Corrosion resistant
does not rust (oxidise)
low density
artificial hip joints, golf clubs. - 15Properties of transition metals:Malleable -layers shift over by one.
High melting points - delocalised electrons.
Good electricity+heat conductors.
can form ions
less chemically reactive than alkali metals
form coloured chemical compounds. - 16Identify the colours of compounds containing : Fe2+, Fe3+, Cu2+Fe2+ Light Green
Fe3+ Brown
Cu2+ Blue - 17Explain the properties and structure of alloys:More lustrous
stronger/harder
Resistant to corrosion
When we mix metals, the layers are disturbed so they no longer move therefore are harder. Irregular shapes, no uniform layer.
- 18Define the term 'alloy'.Alloys are mixtures of two or more different metals (or carbon) made by combining the molten metals.
- 19Blast furnace reactions?
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- Chemistry (UNIT 2) Karteikarten am Metals and their extraction, erstellt von grace thomas am 06/02/2018.
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