Improving Processes And Products Flashcards
What elements do plants need to grow?
Plants require nitrogen, phosphorous and potassium to grow
Signs of Lack of Nitrogen
Poor growth, Yellow Leaves
Signs of Lack of Phosphorous
Poor root growth, Discoloured Leaves
Lack of Potassium
Poor fruit growth, Discoloured Leaves
What do NPK fertilisers do?
Replenish the elements used by plants when they grow providing these essential elements in water-soluble form
Phosphate Ions
PO4 3-
How are the reactants for the Haber process found?
Nitrogen is achieved by fractional distillation of liquified air
Hydrogen is a natural gas that is reacted with steam
What conditions are required for the Haber process?
Passed over an iron catalyst at a high temperature (450) and high pressure (200)
Ammonia is removed by cooling gases so that it liquifies leaving the reaction favouring forwards reaction
Where is ammonia from the Haber process used?
Ammonia produced from the Haber process can be used as a fertiliser in liquid form
It is easier to covert ammonia into an ammonium salt through neutralisation
What are the 3 word equations to produce the ammonium salts used as fertilisers?
Ammonia + Nitric Acid —> Ammonium Nitrate
Ammonia + Phosphoric Acid —> Ammonium Phosphate
Ammonia + Sulfuric Acid —> Ammonium Sulfate
How is potassium sulfate made?
Potassium hydroxide is added to a conical flash with a phenolphthalein. Colour change colourless to pink. Add sulphuric acid from a burette stopping after neutralisation. Add activated charcoal to remove phenolphthalein. Crystallise
How is ammonium sulfate made?
Dilute ammonium solution with methyl orange in a conical flask. Colour change of red/orange to yellow. Add sulphuric acid with burette till neutralisation. Add extra ammonia to ensure reaction is complete
Why is this a compromise?
The yield is 30%. The pressure is high to favour the forward reaction but not too high which is a compromise. The temperature is high to increase the rate of reaction but decreases yield which is a compromise.
What is yield when gases are recycled?
97%
What is the contact process?
The contact process is the way in which sulfuric acid is made
What are the raw materials of the contact process?
Sulphur, Oxygen, Water
What is the first stage of the contact process?
Sulfur burns in air to produce sulfur dioxide. Exothermic reaction
What is the second stage of the contact process?
Sulfur dioxide and oxygen react to make sulfur trioxide
What are the conditions for the second stage of the contact process?
It is a reversible reaction to the conditions are 2 atmospheres, 450 Celsius and Vanadium Oxide catalyst. The temperature has to be over 300 as vanadium oxide does not work otherwise. 96% yield
What is the last stage of the contact process? What are the risks that change the process?
Sulfur trioxide is converted to sulfuric acid. The reaction is very exothermic and produces an acid mist. Therefore sulfur trioxide is passed through concentrated sulfuric acid to make a compound called oleum. Oleum is added to water and the reaction makes a larger volume of concentrated sulfuric acid
What is an ore?
An ore is a rock which has enough metal in it to make it economically viable to extract
How is an ore defined as economically viable?
How easy is it to extract?
How much metal is in the ore?
What is the supply and demand of the metal?
What dictates how a metal is extracted?
The method extraction depends on a metal’s reactivity. Electrolysis is used to extract metals more reactive than carbon. Reduction is used to extract metals more reactive than hydrogen but less reactive than carbon. Metals below require no separation as they are native metals
How is copper extracted from copper fluoride in the air?
Copper fluoride is roasted in the air producing copper oxide. This is heated with carbon in a displacement reaction.
How else can copper be extracted from copper oxide?
Copper can also be extracted with methane to produce copper, carbon dioxide and water
What is the iron ore called?
Haematite
How is iron extracted from haematite?
Iron is extracted using a blast furnace. Coke is burnt in hot air to make carbon dioxide which is reduced by more coke to make carbon monoxide. Carbon monoxide reduces iron oxide to iron at around 1500 Celsius.
What is coke?
Mostly carbon made by heating coal in the absence of air
What is slag and how is it produced?
Slag is calcium silicate and is used to remove impurities from the iron produced.
Calcium carbonate breaks down into calcium oxide in thermal decomposition.
Calcium oxide reacts with silicon dioxide to form calcium silicate
Where is aluminium used?
Name 5
Power cables, saucepans, aeroplanes, bicycles, cars, battleships, cooking foil, cans, space blankets, statues, window frames
What is the aluminium ore called?
Bauxite naturally occurs as Al2O3 and is the most abundant metal in Earth’s crust
How is aluminium oxide separated?
Once it is extracted from the ore it is melted so ions are free to move
It is then put in an electrolysis apparatus where the encasing is the cathode and anodes are held over the top
What is added to aluminium oxide during melting?
Aluminium Oxide has a melting point of 2050 Celsius so cryolite is added to melt it at 850 saving energy
Why do the anodes need to be replaced?
Oxygen reacts with the carbon in the graphite layer around the anode wearing away the anode. Carbon monoxide is also produced and is dangerous
How is aluminium removed from the electrolysis?
Aluminium produced at the cathode is molten and so is tapped away at the cathode. This is why the cathode surrounds the solution
How does bioleaching work?
Bioleaching is where bacteria oxidise iron sulfide ions found in the river and use the energy transferred
Sulfuric acid forms in the presence of water and oxygen
Sulfuric acid breaks down copper sulfide ores and other minerals, releasing copper and other metal ions
What is phytoextraction?
Phytoexraction is where copper ions in soil are absorbed by plants with complexing agent
They become part of the plant when it grows and is then burnt
Copper reacts with oxygen to form copper oxide
Copper is then reacted with sulphuric acid to form copper sulphate
Copper sulphate is separated in electrolysis
What are the advantages of bioleaching?
It is a simple process
It is a cheap process
It uses low grade ores
It is environmentally friendly as fewer waste gases are produced
What are the disadvantages of bioleaching?
It is a slow process
Toxic chemicals may be producced
It has low efficiency
What are the advantages of phytoextraction?
Makes use of low grade copper ore
Requires less energy than smelting
Produces less air pollution
Reduces the amount of waste rock
Close to being carbon neutral
What are the disadvantages of phytoextraction?
Can produce toxic chemicals
Much slower process
Electrolysis afterwards requires lots of energy
What is an alloy?
An alloy is a mixture of 2 elements where one of the main components is a metal
Why are alloys harder than pure metals?
Alloys contain different sized atoms
Atoms are arranged in irregular layers so cannot slide over each other as easily
Alloys are much harder than pure metals
What is steel made out of? Uses?
Iron
Buildings, bridges, cars
What is solder made out of? Uses? Properties?
Tin, Copper
Joining electrical components and copper pipes
Liquid fills gaps
Good conductor of electricity
What is brass made out of? Uses? Properties?
Copper, Zinc
Musical instruments and coins
Conductive
Stronger than pure copper
Resists corrosion
What is bronze made out of? Uses? Properties?
Copper, Tin
Propellers for ships, bells
Stronger than pure copper
Resists corrosion
What is corrosion?
Corrosion is the destruction of materials by chemical reactions with substances in the environment
What is rusting? Equation? What is needed?
Corrosion Iron
Oxygen, Water
Iron + Oxygen + Water —> Hydrated Iron (III) Oxide
What are ceramics? Examples?
Ceramics are hard, non-metallic (lack metal attributes) structures.
Brick, China, Porcelain, Glass
What is the structure of ceramics?
Ceramics contain metals and non-metals to form giant ionic lattices or giant covalent structures.
What are the properties of ceramics?
High melting point
Hard, Stiff, Brittle
Poor conductors of heat and electricity
Inert
What makes a structure transparent?
Glass is transparent because its giant structure is very irregular.
What are composites?
Composites are made from two or more materials combined together, each with different properties. One material acts as a binder for the other material, improving a desirable property neither can provide on its own
What materials make concrete? What are the properties of concrete?
Cement, Air, Water, Gravel
Concrete is easily workable when molten
Concrete has a very high compressive strength and so can withstand stress
Concrete is highly durable and withstands exposure to elements
What materials make steel-reinforced concrete? What properties does it have?
Steel, Concrete (Cement, Air, Water, Gravel)
High compressive strength
High tensile strength
Resistant to fire and weathering (durable)
What materials make plywood? What properties does it have?
Plywood is made from different hardwoods and softwoods
High impact resistant
Water and chemical resistant with fireproofing
Flexible and more malleable
What is an LCA? What 4 factors?
A life cycle assessment is an analysis of the impact of making, using, and disposing of a manufactured product.
Sustainability, Environmental Impacts, Lifespan, Disposal
What is the purpose of an LCA?
Allows you to identify what could be improved, or alternative methods
What is the purpose of recycling materials?
Unless they are recycled, materials will end up in a landfill site. Conserving limited raw materials and energy resources. Reduces waste
What happens during the recycling processing of metals?
Metals are melted by heating, and molten metal are poured into moulds to produce new blocks called ingots.
How are papers processed in recycling?
Papers are mixed with water, cleaned, and then rolled and heated to make new paper
How is glass and polymers processed in recycling?
Glass and polymers are melted by heating and moulded into new glass or polymer objects
How can rusting be reduced?
Painting, coating with oil/grease/plastic, plating with zinc, plating with tin
What is sacrificial protection?
Sacrificial protection involves iron being in contact with a more reactive metal. The more reactive metal will corrode first protecting the iron. This is because the more reactive metal will more easily lose electrons and so is oxidised first.
What is Duralumin made from? Uses?
Aluminium, Copper
Low density Aircraft
