Chemistry - in industry.

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What makes a metal harder to extract?
The more reactive a metal is, the harder it is to extract.
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What is a reduction reaction and what happens in it?
A reaction that separates a metal from the oxygen in it's oxide. The reducing agent is the substance that reduces the metal (oxidised). Carbon is the most common.
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Methods of extraction are linked to the order of reactivity, why is this?
because the more reactive elements form compounds more readily, e.g. carbons more reactive then iron so 'steals' oxygen from iron oxide. Only able to do this to a metal less reactive then itself.
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What makes a very reactive metal difficult to get out of a compound?
they form very stable ores
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What could be used instead of extracting a metal via order of reactivity?
electrolysis
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Whats aluminiums main ore? Whats left after mining and purifying?
bauxite (Al203) After a white powder is left.
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What is cryolite used for?
bauxite has a melting point over 2000C - EXPENSIVE. So instead the aluminium oxide is dissolved in molten cryolite which brings the melting point down to 900C making it cheaper and easier.
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Describe the process of electrolysis.
positive ions are attracted to cathode(negative), where they pick up electrons then sick to the bottom. Negative ions attracted to positive electrode (anode) where they lose electrons the atoms then react.
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Example of complete electrolysis equation for aluminium.
aluminium oxide ----> aluminium and oxygen
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Why is electrolysis so expensive?
it uses a lot of electricity, heat and replacement of electrodes.
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What are the raw materials for extracting iron?
iron ore, coke (mostly carbon), and limestone.
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How to reduce iron ore to iron?
hot air blasted into furnace, makes coke burn faster raising temp to 1500C. C + 02 ---> C02. C02+C->2C0. Carbon monoxide reduces iron ore to iron, 3CO+FE203->3CO2+2FE. molten iron drains out bottom and is tapped off.
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How to remove impurities when extracting iron.
limestone redices sand, and is decomposed via heat to calcium oxide and C02, CaC02-> CaO+C02. The calcium oxide then reacts with sand to form calcium silicate(****) which is moltern and can be tapped off, Ca0+ Si02->CaSi03.
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What state is **** and what is it used for?
solid. used for road building and fertiliser.
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What properties do iron and aluminium have in common?
dense and lustrous(shiny). high melting points. strong, malleable, good conductors of heat and electricity.
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What are the properties and ingredients of cast iron?
iron, carbon, chromium. hard but brittle, used for cooking.
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What are the properties and ingredients of stainless steal?
alloy made of iron carbon and some other metals. hard, doesnt rust.
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What are some uses of aluminium?
reacts quckily with oxygen in air to stop and other reactions taking place. doesn't corrode easily. drinking cans, light, less dense.
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Describe crude oil being separated into different hydrocarbons using fractional distillation.
oil heated until most turned into gas, gases enter fractioning column, where theres temperature gradient when it reaches the lower temp it condenses.
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How do different length hydrocarbons drain out in fractional distillation?
long chains have high boiling points so condense and drain out at bottom. Short chains have lower boiling points
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Describe the materials in the distillation process and their uses?
refinery gases, heating, 3C in chain. gasoline, fuel 8C. Naphtha, makes plastic 10C. kerosene, jet engines 15C. diesel, fuel, 20C. fuel oil, fuel for big ships, 40C. bitumen, roads. 70C.
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How do sulphur dioxide and nitrogen oxides come from burning fuel?
sulphur dioxide comes from sulphur impurities in fossil fuels. Nitrogen oxides are created when the temp is high enough for the oxygen and nitrogen in the air to react.
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How is acid rain formed?
sulphur dioxide mixes with clouds it forms dilute sulphuric acid. 2SO2+02+2H20->2H2SO4. nitrogen oxides can also form nitric acid in clouds.
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What does acid rain do?
causes lakes to become acidic making animals die. kills trees and damages limestone buildings and stone statues.
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Why are shorter length hydrocarbons more useful?
they have lower boiling points.
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How does cracking work?
cracking is a form of thermal decomposition which means breaking molecules down into simple molecules by heating them
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How to do cracking in a lab?
heat paraffin, heat silica after a few seconds, alternate between the two until the paraffin vaporises and the catalyst(silica) glows red, the heated paraffin vapour cracks as it passes over the heated catalyst.
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When doing cracking in a lab, where are the alkanes and alkenes collected?
alkanes: collect at end of boiling tube. Alkenes: travel down delivery tube.
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How are additional polymers made?
under high pressure and with a catalyst, many small molecules open up double bonds and 'join hands' (polymerise) to form long saturated chains - polymers.
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describe repeat unit and monomer of poly(propene).
j
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Uses of polymers?
poly(ethene) light, stretchable, ideal for making packaging- plastic bags. poly(propene) tough, flexible, heat resistant, used for kettles and carpets.
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why is it difficult to get rid of polymers?
inert(dont react easily) because the '=' is very strong. so takes a long time for additional polymers to biodegrade. burning plastics releases toxic gases. REUSABLE.
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How do nitrogen and hydrogen make ammonia?
N2+3H2 = 2NH3 (+ HEAT). Nitrogen obtained from air, H comes from natural gases, 200 atmospherics, 450C iron catalyst, reaches dynamic equilibrium.
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What are the compromises made in the harbour process?
pressure is high to get big % yeild and favours forward reaction. high temp makes reaction go faster but makes equilibrium go wrong way so less yield of ammonia, lower temp makes ammonia burn slower. 450 is compromise.
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What does the catalyst do in the harbour process?
the iron catalyst makes it go faster by providing alternate pathway with out affecting % yield.
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What is ammonia used for?
in Ostworld process to make nitric acid. and reacted with nitric acid to get ammonium nitrate- a good fertiliser because it has 2x as much nitrogen from 2 sources.
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Other cards in this set

Card 2

Front

What is a reduction reaction and what happens in it?

Back

A reaction that separates a metal from the oxygen in it's oxide. The reducing agent is the substance that reduces the metal (oxidised). Carbon is the most common.

Card 3

Front

Methods of extraction are linked to the order of reactivity, why is this?

Back

Preview of the front of card 3

Card 4

Front

What makes a very reactive metal difficult to get out of a compound?

Back

Preview of the front of card 4

Card 5

Front

What could be used instead of extracting a metal via order of reactivity?

Back

Preview of the front of card 5
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