Metal extraction and all that Flashcards
What is the empirical formula for ethanol?
C2H5OH
What is the difference between batch and continuous?
Batch - small amount of a substance made at a time.
Continuous - Large amounts made all the time. Many industrial processes use this method.
What do fertilisers do?
They replace the elements used by plants as they grow - Nitrogen, Phosphorus and Potassium.
What are the symptoms of a plant having a phosphorus deficiency?
Poor root growth, discoloured leaves.
What are the symptoms of a plant having a potassium deficiency?
Poor fruit growth, discoloured leaves.
What are the symptoms of a plant having a nitrogen deficiency?
Poor root growth, yellow leaves.
Why are fertilisers made in powdered form?
Liquids risk spillages and are therefore potentially dangerous to the environment. Powders are still soluble, which is necessary for fertilisers as plant roots can only absorb these elements if they are in a water-soluble form.
What is an ore?
A rock or mineral that contains enough metal to make it economical to extract the metal.
Which ore contains copper (II) carbonate?
Malachite.
What does the ore bauxite contain?
Aluminium oxide. (Al2O3)
What does the ore haematite contain?
Fe2O3 - iron (III) oxide
Which is more reactive, magnesium or carbon?
Magnesium.
When comparing reactivity, how can you tell which elements have the largest gap in the reactivity series?
The most vigorous reaction shows the largest gap.
What is used to extract iron?
A blast furnace.
What are the raw materials used in iron extraction and why are they used?
Iron ore (haematite, which contains iron III oxide) used because iron has to be extracted to extract iron do i seriously have to explain this
Coke - mostly carbon, used to react with oxygen to make carbon dioxide
Limestone - used to purify the iron. Gets rid of the sandy impurities.
What is the role of yeast in fermentation?
Yeast cells contain enzymes that catalyse the conversion of glucose to carbon dioxide and ethanol.
What are the two methods of producing ethanol?
Renewably producing ethanol through fermenting plant sugars, using yeast as a catalyst.
Non-renewably producing ethanol through the hydration of ethene.
Is it more expensive to produce ethanol renewably or non-renewably?
Non-renewably.
Which method of producing ethanol has the highest percentage yield?
Hydration of ethene, with around 95%. Fermenting sugars has about 15%.
What are some disadvantages of producing ethanol through fermenting sugars?
The percentage yield is only 15%.
The ethanol produced is impure and requires filtering and fractional distillation.
What equipment will you need to carry out laboratory fermentation?
Conical Flask, Bung, Delivery Tube, Boling Tube.
What are some disadvantages of producing ethanol through the hydration of ethene?
The cost of raw materials (ethene) is high.
The temperatures and pressures needed to hydrate ethene are incredibly high, making them expensive and potentially hazardous to workers.
Energy requirements are high, making it an expensive process.
Why is ethene a non-renewable material?
It is obtained from crude oil, which is a non-renewable raw material.
Why must fermentation only be carried out at moderate temperatures and pressures?
The enzymes in the yeast cells will denature if the temperature is above 50°C, and will be inactive if temperatures are too low. Fermentation is carried out at 35°C at normal atmospheric pressure.
What is the first formula in the steps to extract copper?
First the copper (II) sulfide is roasted in the air.
copper (II) sulfide + oxygen –> copper(II) oxide + sulfur dioxide
What is the second formula in the two steps to extracting copper?
The copper oxide is heated with carbon.
Copper(II) oxide + carbon –> copper + carbon dioxide
This is an example of a redox reaction.
Give the equipment used to extract copper from copper sulfide through heating with methane.
Bunsen burner, reduction tube, delivery tube, bung
How can you extract copper by using charcoal?
Charcoal is mostly carbon, so heating it strongly in a crucible with a lid (to stop powders from escaping and the carbon burning) then transferring the contents to a beaker of water allows the copper to sink to the botom while the charcoal is suspended in the water.
What is the first reaction to take place in the blast furnace?
Coke burns in the hot air, making carbon dioxide.
Carbon + oxygen –> carbon dioxide
What is the second reaction that takes place in the blast furnace?
More coke reduces the carbon dioxide, making carbon monoxide.
Carbon dioxide + carbon –> carbon monoxide
What is the third reaction that takes place in the blast furnace?
Carbon monoxide reduces iron oxide to iron.
Carbon monoxide + iron (III) oxide –> carbon dioxide + iron
What is limestone?
Calcium carbonate
CaCO3
What is slag made of?
Molten calcium silicate.
What are the two reactions that take place in the making of slag?
Calcium carbonate decomposes in the high temperatures.
calcium carbonate –> calcium oxide + carbon dioxide
The calcium oxide formed reacts with silica from the sandy impurities to form calcium silicate (slag)
Calcium oxide + Silicon dioxide –> calcium silicate
WHAT IS THE SLAG
THE SLAG IS ON TOP
State the name and formula of the main reducing agent in the balst furnace.
Carbon monoxide. CO
Why must aluminium be extracted through electrolysis?
It is more reactive than carbon.
Why can electrolysis only work if the compound is in molten form or a solution?
Ionic compounds do not conduct electricity in solid form, as their ions are in fixed positions and therefore cannot move to carry an electrical charge.
If aluminium has such high melting points, and does not dissolve in water, how is it electrolysed?
Aluminium oxide is dissolved in molten cryolite. Cryolite has a much lower melting point than aluminium oxide, and allows electrolysis to happen at about 950°C.
In the elctrolysis of aluminium, what is the cathode and what is the annode?
The graphite lining of the electrolysis cell is the cathode.
A series of large graphite blocks act as the annodes.
What is made at the anodes in the elctrolysis of aluminium?
Oxygen is produced at the anodes, which reacts with the hot graphite anodes to make carbon dioxide.
Suggest why the anodes in an aluminium electrolysis cell may need to be replaced every few weeks.
Since the oxygen produced at the anode will react with the hot graphite of the anodes to make carbon dioxide, the anodes will have to be replaced every few weeks as the reactions wear them away.
How does cryolite reduce energy costs?
It reduces the amount of energy needed to melt aluminium and allows electrolysis to happen with lesser energy costs.
What is phytoextraction?
It is when a crop is planted in soils containing a low grade-ore in order for it to uptake ions from this ore through its roots, before being harvested and burned to extract the target metal in a high concentration.
What is it called when abandoned mines flood, causing metal sulfides to oxidise underwater to produce sulfuric acid, which reacts with metal ores and forms soluble metal compounds that leave with the exiting water as it drains from the mine?
BIIIIIG GASP bioleaching.
What are ceramics?
Hard, non-metallic materials.
What are brick, china, porcelain or glass all examples of?
Ceramics.
How are ceramics structured?
They are constructed of metals and non-metals combined to form giant ionic lattices or giant covalent structures.
Define a giant covalent structure.
A structure that consists of many non-metal atoms joined by covalent bonds and arranged in a regular repeating pattern called a giant lattice.
Give three properties of ceramics. Explain why they have these properties.
- High melting points (due to strong intermolecular forces in a giant covalent structure)
- Hard and stiff, but brittle (as atoms are not arranged in a way that allows them to slide over each other in layers)
- Poor conductors of electricity and heat (no free ions or electrons to move to carry an electrical charge)
Give four methods of reducing corrosion.
- Painting
- Galvanising (plating with zinc)
- Plating with tin.
- Coating with oil, grease, or plastic.
Define corrosion.
The reaction of a metal with substances in its surroundings (air and water.)
What happens when iron and steel corrode?
Rusting.
What kind of reaction is rusting?
A redox reaction.
What must be present for iron to rust?
oxygen and water.
Describe how silver corrodes.
It corrodes in the presence of hydrogen sulfide, H2S, a gas produced naturally by bacteria. The hydrogen sulfide rescts with silver when oxygen and water are also present. The resction corrodes the silver, producing a thin layer of black silver sulfide.
Why don’t metals such as gold or platinum corrode?
They are too unreactive.
What are alloys?
A mixture of two or more elements, at least one of which is a metal.
Give three examples of alloys.
Brass, Steel and Bronze.
Give an advantage of alloys.
They are often stronger and harder than the individual metals they contain.
What is an LCA?
A life cycle assessment is a ‘cradle to grave’ analysis of the impact of making, using and disposing of a manufactured product.
What should an LCA include data about?
Sustainability
Environmental impact
Lifespan of the product
Disposal
What is a composite material?
A material composed of two or more materials combined, each with different properties.
Give an example of a composite material.
Fibreglass.
What do many composite materials consist of?
Fibres embedded in a polymer resin.
