Using Resources Flashcards
Describe the Difference Between Finite and Renewable Resources
-A finite resource will run out as the rate at which it is used is faster than the rate at which it is made.
-A renewable resource will not run out as the rate at which it is used is slower than the rate at which it is made.
Explain what is Meant by Sustainable
To be sustainable, humans must be able to satisfy their needs in a way that does not prevent future generations from satisfying their needs.
Describe the Difference Between Pure and Potable Water
-Potable water is water that is fit to drink.
-Pure water is water that contains no other additives.
State Sources of Fresh Water
-Porous underground rocks (aquifers).
-Rainwater falling to the ground and collecting as surface water (replenishing freshwater in rivers and lakes).
Describe the Process of Making Potable Water from Fresh Water
-Choose an appropriate source of fresh water, such as rivers, streams, lakes and boreholes.
-Grated bars or a wire mesh are used to screen out large objects. To remove sand and soil, the water is allowed to sit in a settlement tank.
-To remove smaller particles of dirt, chemicals are added to aggregate the smaller particles so they also settle out.
-To remove smaller particles of mud and grit, the water is passed through a microfilter. Undissolved particles are also passed through filter beds.
-To remove harmful bacteria, the water is sterilised by adding chlorine, ozone or UV light. To change the pH, add acid if greater than 7 or add alkali if less than 7.
Describe the Processes of Making Potable Water from Seawater
-In reverse osmosis, the sea water is passed through a series of filters or membranes which gradually reduce the levels of dissolved minerals.
-In distillation, the seawater is heated to evaporate the water (leaving the minerals behind). The pure water vapour is then condensed back to liquid water and collected.
Describe the Disadvantages of Distillation and Reverse Osmosis
-Both reverse osmosis and distillation use large amounts of energy. This makes them extremely expensive.
-Reverse osmosis involves an expensive membrane which needs replacing.
-Distillation is a batch process.
Describe a Method for Analysing a Water Sample
-First, check the pH of the water sample by adding a drop of water to a piece of universal indicator paper. Then, use a balance to to find the mass of an empty evaporating basin.
-Pour 10 cm3 of the water sample into the evaporating basin.
-Heat the evaporating basin on a tripod and gauze using a Bunsen burner until solids start to form and the water has evaporated.
-Remove the sample from heat and once cool, weigh the evaporating basin again and calculate the mass of the solids that was dissolved in the water.
Explain why pH 7 Does Not Show that the Water Sample is Pure
-Pure water does have a pH of 7. However, pure water also must contain no dissolved substances.
-It is possible for a sample of water to have a pH of 7 but still to contain dissolved substances. This would not be pure water.
Explain how the Results of Analysing a Water Sample Will Show that it is Pure
-If the water sample is pure then the final mass of the empty evaporating basin (after heating) will be the same as the initial mass of the empty evaporating basin (before heating).
-This shows that the water contained no dissolved salts.
-If the water had contained dissolved salts, they would have been left after the water evaporated.
-This would have meant that the mass of the empty evaporating basin was greater after heating than before.
State Causes of Anomalous Results when Analysing a Water Sample
-If the mass is too large, the sample has not been heated to constant mass. The evaporating basin may also contain condensation underneath.
-If the mass is too small, the evaporating basin may not have been clean at the start. There may have also been solid lost during transfer from heat to mass.
Describe a Method for Purifying a Sample of Water
-Place the water sample in the conical flask. Set up the apparatus for distillation as shown in the diagram.
-Heat the water using the Bunsen burner until it boils. Then reduce the heat so that the water boils gently.
-The distilled water will collect in the cooled test tube. Collect about 1 cm depth of water in this way, then stop heating.
-Analyse the distilled water by determining its boiling point. Pure water should have a boiling point of 100ºC.
Explain why Iced Water is Used when Purifying a Sample of Water
The purpose of the iced water is to cool the test tube down so that the water vapour condenses.
Explain why Waste Water can not be Returned Directly Back to Rivers
-Waste water from homes and farms contains a great deal of harmful microorganisms and organic molecules.
-Returning this untreated waste water to rivers would be
extremely dangerous to aquatic organisms such as fish.
-Bacteria in the river would feed on the organic molecules. The bacteria would reproduce and before long there would be a huge number of bacteria.
-These bacteria would use all of the oxygen in the water. Lack of oxygen would cause other organisms to die.
Describe the Treatment of Waste Water
-The sewage is screened- this involves passing the water through fine metal meshes. These filter out solids and grit.
-Then, its allowed to stand in a settlement tank and undergoes sedimentation- the heavier suspended solids sink to the bottom to produce sludge while the lighter effluent floats to the top.
-The effluent is removed and treated by biological aerobic digestion. Air is pumped through the water to encourage aerobic bacteria to break down organic matter.
-The sludge is removed and treated by anaerobic digestion. This produces methane gas which can be used as an energy source and remaining digested waste as fertiliser or biofuel.
-Water can be further treated by adding chlorine, ozone or using UV light before being returned to waterways.
Describe the Difference Between High Grade and Low Grade Ores
-An ore is a rock containing enough of a metal to be economically viable to extract a metal from it.
-High grade ores have a higher percentage of the desired metal.
-Low grade ores are only just economically viable, or only viable with new methods.
Describe the Process of Smelting (Carbon Reduction)
-Smelting is used for high grade ores.
-It involves using carbon and a high temperature to displace a less reactive metal.
Describe the Advantages and Disadvantages of Smelting
Advantage:
-Charcoal is cheap
Disadvantages:
-Forms carbon dioxide (a greenhouse gas)
-Uses a high temperature which needs a lot of energy so is expensive.
Describe the Process of Displacement
-Displacement is used for high grade ores.
-It involves a more reactive metal taking the place of a less reactive metal that is already bonded in a compound.
Describe the Advantages and Disadvantages of Displacement
Advantage:
-Scrap iron can be used
Disadvantage:
-More expensive reactive metals have to be used
Describe the Process of Electrolysis
-Electrolysis is used for high grade ores.
-It involves using electricity to split a compound into its elements.
Describe the Advantages and Disadvantages of Displacement
Advantages:
-Produces the highest purity of metal
-Works on the most reactive metals
Disadvantage:
-Lots of energy is needed so is expensive
Describe the Process of Phytomining
-Phytomining is used for low grade ores.
-It involves growing plants on land containing copper ores. They absorb the copper but can’t use or get rid of it so it builds up in the leaves.
-The plants are then burnt to produce ash. This leaves behind copper. The ash is also dissolved in acid to produce a solution of a copper compound.
-Copper can then be extracted from the solution by electrolysis or displacement with a more reactive metal. e.g scrap iron.
Describe the Advantages and Disadvantages of Phytomining
Advantage:
-It is a carbon neutral process- it takes in carbon dioxide when the plants are growing and releases it when the plants are burnt
Disadvantages:
-It is time consuming so inefficient
-There are additional environmental impacts from farming the land such as carbon dioxide produced by burning fuels to drive tractors
Describe the Process of Bioleaching
-Bioleaching is used for low grade ores.
-It involves bacteria converting copper compounds in the chosen ore into soluble copper compounds, separating out the copper from the ore in the process.
-The ore is sprayed with the bacteria. Time is then allowed for chemical reactions to take place. The bacteria then produce leachate.
-This contains copper ions which can be extracted by electrolysis or displacement with a more reactive metal. e.g scrap iron.
Describe the Advantages and Disadvantages of Bioleaching
Advantage:
-Can be carried out over large areas without the need for intervention
Disadvantage:
-Bacteria often produce sulfur which reacts to form sulfur dioxide and contributes to acid rain.
Describe the Difference Between Reuse and Recycle
Reuse- using the same materials again for the same process.
Recycle-using the materials for a different purpose.
Describe the Consideration of Extracting the Raw Materials in a Life Cycle Assessment
-Extracting raw materials needed for a product can damage the local environment.
-Raw materials often have to be processed to extract the desired materials and this often needs large amounts of energy.
-Consideration must also be taken over whether the material is finite or renewable.
Describe the Consideration of Making the Product in a Life Cycle Assessment
-Manufacturing products and their packaging can use a lot of energy.
-Waste products must also be considered such as the amount of carbon dioxide produced as these can cause pollution.
Consideration must also be taken over the number of processing steps.
Describe the Consideration of Using the Product in a Life Cycle Assessment
-How long a product is used for or how many years it gets without needing to be replaced is an important factor.
-The use of a product can also damage the environment for example driving cars involves burning fossil fuels.
Describe the Consideration of Disposing the Product in a Life Cycle Assessment
-A product that can be recycled will be more environmentally friendly than a product that cannot.
-A product that is non-toxic and biodegradable is also beneficial.
Describe the Problems with Life Cycle Assessments
-It can be very difficult to accurately work out the environmental impact of different processes so sometimes we have to make estimates.
-Also, lifecycle assessments may be biased, for example to make a product look less harmful to the environment than it actually is.
Describe the Difference Between Corrosion and Rusting
-Corrosion is the destruction of a material by chemical reactions in the environment.
-Rusting is the corrosion of iron involving the reaction with both water and oxygen.
Iron + Oxygen + Water → Hydrated Iron (III) Oxide
Describe a Reaction Between Iron and Oxygen
-Place calcium chloride and a iron nail into a test tube. Place a bung on top.
-This tests for the reaction between iron and oxygen.
-Calcium chloride absorbs moisture from inside the test tube. The bung also prevents any more air from entering the test tube.
-There will be no change observed because rusting cannot take place as there is no water in the reaction.
Describe a Reaction Between Iron and Oxygen and Water
-Pour distilled water into a test tube so that it is not completely filled. This leaves a space of air.
-This tests for the reaction between iron, oxygen and water (rusting).
-An orange layer will form around the nail as both oxygen and water are present so rusting can take place. Hydrated iron (III)oxide is formed.
Describe a Reaction Between Iron and Water
-Pour boiled water into a test tube so that it is almost full. Fill the rest of the space with a layer of oil.
-This tests for the reaction between iron and water.
-The layer of oil prevents oxygen from dissolving in the water or entering the test tube.
-There will be no change observed because rusting cannot take place as there is no oxygen in the reaction.
Describe how Barrier Methods Work to Prevent Rust
-Barrier methods provide a layer that stops oxygen or water (or other corrosive materials) reaching the item that you wish to protect e.g. paint it or cover it in grease.
-Electroplating is another example of a barrier method. It is a way of applying a thin layer of metal on the surface of another metal, using electrolysis.
Explain why Aluminium Does Not Need Protection from Corrosion
-Aluminium is quite a reactive metal. This means that the surface of aluminium reacts with oxygen in the air.
-However, the thin layer of aluminium oxide produced now protects the rest of the aluminium underneath from corrosion.
Describe how Sacrificial Protection Works to Prevent Rust
-Sacrificial protection involves adding a more reactive metal so that it reacts instead of the object being protected.
-Galvanisation is an example of sacrificial protection. It involves coating an iron object in a layer of zinc. As zinc is more reactive, it will react instead of iron.
Explain why Alloys are Harder than Pure Metals
-Alloys are a mixture of different sized atoms.
-This means the layers become distorted.
-This means the layers can’t slide over each other.
-Therefore, alloys are harder than pure metals.
Describe the Properties of Bronze
-Bronze is an alloy of copper and tin.
-It is resistant to corrosion and tough.
-The resistance to corrosion protects it against the weather.
-Often used for statues.
Describe the Properties of Brass
-Brass is an alloy of copper and zinc.
-Harder than pure copper.
-The hardness makes them robust.
-Often used as doorhandles.
Describe the Properties of Gold
-Gold is an alloy of gold, copper, silver and zinc.
-The alloy is harder than the element and comes in different colours.
-Its properties make it pretty and resistant to corrosion.
-Often used in jewellery.
Describe the Properties of Low Carbon Steel
-Low carbon steel is an alloy of iron and 0.05 to 0.309% carbon.
-It is soft enough to easily shape.
-It does not shatter on impact.
-Often used for car bodies.
Describe the Properties of High Carbon Steel
-High carbon steel is an alloy of iron and 0.8 to 2.0% carbon.
-It is extremely hard.
-It is also brittle.
-Often used to make cutting tools.
Describe the Properties of Stainless Steel
-Stainless steel is an alloy of iron with chromium and nickel.
-It is resistant to corrosion.
-The resistance to corrosion protects it form the weather.
-It is used to make cutlery.
Describe the Properties of Aluminium
-Aluminium is an alloy of aluminium and other metals (e.g. titanium).
-It is low density, strong and resistant to corrosion.
-It is used to make aircraft.
Describe the Haber Process
-The Haber Process is used to manufacture ammonia, which can be used to produce nitrogen-based fertilisers.
-On cooling, the ammonia condenses and is removed. By removing the ammonia from the reaction, the equilibrium shifts to the right, which increases the yield
-The remaining hydrogen and nitrogen are recycled and returned to the reaction vessel via the compressor.
-Recirculating the unreacted nitrogen and hydrogen back over the catalyst increases the yield by giving the molecules more chance to react together.
Describe the Materials and Conditions Used in the Haber Process
-The Haber Process uses nitrogen (from the air) and hydrogen (from natural gases such as methane).
-It takes place at 450℃ (compromise of temperature), 200 atmospheres of pressure (compromise of pressure) and uses an iron catalyst.
Explain why the Temperature Chosen for the Haber Process is a Compromise
-A high temperature increases the rate of reaction because particles have more energy so there are more frequent collisions with energy greater than than activation energy.
-However, the forward reaction is exothermic so decreasing the temperature shifts the position of equilibrium to the right to increase the yield.
-Therefore, a compromise in temperature is needed.
Explain why the Pressure Chosen for the Haber Process is a Compromise
-A high temperature increases the rate of reaction because there are more particles in a given volume so there are more frequent collisions with energy greater than than activation energy
-There are also more moles of gas on the left so increasing pressure shifts the position of equilibrium to the right to increase the yield.
-However, a compromise is still needed because a high pressure is expensive and dangerous (explosions).
Explain why an Iron Catalyst is Used in the Haber Process
-The catalyst increases the rate of reaction without being used up because it provides an alternative pathway with lower activation energy.
-Catalysts have no effect on the position of equilibrium.
Describe NPK Fertilisers
-NPK fertilisers contain formulations of compounds, containing three ‘macro nutrients’- Nitrogen, Phosphorous and Potassium.
-Fertilisers improve agricultural productivity because they make crops grow larger and faster.
Describe the Differences Between Making Fertilisers in the Lab to Making it on an Industrial Scale
-Lab fertiliser is made on a small scale whereas industry fertiliser is produced on a larger scale.
-It is safer to make fertiliser in the lab than on an industrial scale.
-Lab fertiliser is made using glass equipment whereas industry fertiliser is made using stainless steel equipment.
-lab fertiliser is made at room temperature and atmospheric pressure whereas in industry, a much higher pressure and temperature is used.
-Lab fertiliser is made in a batch process whereas industry fertiliser is made in a continuous process.
Describe the Production of Soluble Phosphates
-Phosphate rock is mined from the ground. The phosphate salts in the rocks are insoluble so plants can’t use them as nutrients. They are reacted with acid to make soluble phosphates.
-Reacting phosphate rock with nitric acid produces phosphoric acid and calcium nitrate.
-Phosphoric acid is a strong acid and would be extremely damaging to crops. It needs to be converted to a neutral compound (ammonium phosphate).
-Reacting phosphate rock with sulfuric acid produces calcium sulfate and calcium phosphate (single superphosphates).
-Reacting phosphate rock with phosphoric acid only produces calcium phosphate (triple superphosphate)
Describe the Difference Between Ceramics and Composites
-Ceramics are non-metal solids with a high melting point that are not made from carbon based compounds.
-Composites are made of one material embedded in another. Fragments of a material (reinforcement) are surrounded by a matrix acting as a binder.
Describe the Properties of Clay
-Clay is a soft material when dug out of the ground so can be moulded into different shapes. When its fired at high temperatures, it hardens to form a clay ceramic.
-Its ability to be moulded when wet and then harden makes clay ideal for making pottery and bricks.
-It is malleable when wet because the layers slide over each other.
-When heated it is brittle because heating removes water molecules which forms perfectly straight layers. Cracks then form between the layers.
Describe the Properties of Soda Lime Glass
-It is made by mixing sand, sodium carbonate and limestone. It is then heated to melt, shaped and cooled.
-Soda lime glass has a high melting point.
-It is used to make everyday glass items such as windows and glass bottles
Describe the Properties of Borosilicate Glass
-It is made by mixing sand and boron trioxide. It is then heated to melt, shaped and cooled.
-Borosilicate glass has a higher melting point than soda lime glass so will not melt when heated. It is also stronger and less likely to shatter.
-It is used to make lab equipment )test tubes) and measuring equipment.
Describe the Properties of Different Composites
-Concrete is made from aggregate (a mixture of sand and gravel) embedded in cement. This makes it very string so is used as a building material.
-Fibreglass consists of fibres of glass embedded in matrix made of polymer (plastic). It has a low density but is very strong. It is used to make skis, bots and surfboards.
-Carbon fibre composites also have a polymer matrix. the reinforcement is made from chains of carbon atoms bonded together or from carbon nanotubes.
-These composites are strong and light so are used to make car and aircraft parts.
Describe Thermosetting Polymers
-Thermosetting polymers do not melt when heated.
-This is because the polymer strands are held to each other by strong crosslinks (usually covalent bonds). These are so strong that they are not broken by heat.
Describe Thermosoftening Polymers
-Thermosoftening polymers melt/soften at high temperatures. They can be moulded and keep their new shape when cooled.
-The polymer strands are held to each other by weak intermolecular forces of attraction only.
-If the polymer is heated, these intermolecular forces of attraction are weakened or broken. This allows the polymer strands to move away from each other and the polymer loses its structure.
-If the polymer is cooled, the intermolecular forces of attraction reform. This means that the polymer now reforms into a solid.
Describe Low Density Polyethene
-Consists of branched chains. These prevent the chains getting too close so there is a lot of space between them.
-It is made by addition polymerisation of ethene using high pressure and a trace of oxygen.
-It is flexible so used for bags.
Describe High Density Polyethene
-Consists of linear chains. There is very little space between chains so it is very dense.
-It is made by addition polymerisation of ethene at 50℃ with a catalyst.
-It is rigid at room temperature so used for water tanks and drainpipes.
