Section 5 Chemistry In Industry Flashcards
The more reactive the ………… To extract from the compound
Harder
What are metal ores often?
Oxides
What are methods of extraction linked to?
Order of reactivity
How can metals that are less reactive than carbon be extracted?
Reduction reaction - heating the ore with carbon monoxide
How are very reactive metals extracted?
Electrolysis
What is the main ore in aluminium?what is left after mining?
Bauxite
White powder
Why Is cryolite used?
Brings temperature down to 900 to 2000 degrees
Cheaper
What are electrolytes made of?
Graphite
What is the negative and positive electrode called?
Negative - cathode
Positive - anode
Why does the positive electrode need constant replacement?
It reacts with the oxygen to make CO2 which corrodes it
When extracting iron what are the raw materials?
Iron ore
Coke - pure carbon
Limestone
What are the steps for extracting iron?
Hot air - temp 1500 is blasted in the furnace
The coke burns and produces CO2
Carbon + oxygen ……… Carbon dioxide
CO2 reacts with the unburnt coke to form carbon monoxide
Carbon monoxide reduces iron ore to iron
3CO + FeO3 …… 3CO2 + 2Fe
How is iron collected?
Is molten and very dense so runs straight to the bottom of the furnace to be tapped off
How are impurities removed?
Sand - removed by limestone
Limestone is decomposed by heat into calcium oxide and CO2
Calcium oxide reacts with sand to for calcium silicate/ slag
What is slag used for?
Road building
Fertiliser
What do iron and aluminium have in common?
Both dense and shiny High melting points High tensile strength - strong and hard to break Malleable Good conductors Heat energy
What is a metal ore?
Compound that contains enough of a metal worthwhile for extracting
What is iron used for?
Wrought iron - ornamental gates and railing
Cast iron - mixture of iron carbon and silicon, manhole covers
Steel - carbon and iron, car bodies and griders
Stainless steel - doesn’t rust, in knives and forks
What is aluminium used for?
Doesn’t corrode - drink cans
Less dense than iron - bike frames and aeroplanes
What is crude oil separated into?
Different hydrocarbon fractions
What stops separate liquids running back down in a fractional column?
Bubble caps
What is the order from top to bottom of products for crude oil fractionalisation?and a use for each one
Refinery gas - bottles gas, manufacturing Gasoline - car fuel Naphtha - chemical industry, plastics Kerosene - jet engines, paint Diesel - fuel Fuel oil - central heating Bitumen - road surfaces
Explain the effects of pollutants?
Carbon monoxide - incomplete combustion, less oxygen in blood
Sulfur dioxide - sulfur impurities
Nitrogen oxide - high enoug temperature to react in air, eg in car engines
What is acid rain?
Caused by sulfur dioxide and nitrogen oxides
When mix with the clouds they make sulfuric and nitric acid
Acid rain makes lake acidic and kills trees
What is cracking? How does it work?
Splitting up long chains of hydrocarbons
More demand for shorter hydrocarbons
Form of thermal decomposition
What are the conditions for industry cracking?
Temp - 600-700
Silica and alumina- catalysts
What is an addition polymer?
Formed when lots of small molecules called monomers join together to make a polymer.
These monomers have a carbon double bond (alkenes).