Using resources Flashcards
What are ceramics?
Non-metal solids with high melting points that aren’t made from carbon-based compounds
Give 2 examples of ceramics
Glass and clay
What is clay and why is it useful?
.Soft when dug up so can be molded into different shapes
.When it’s fired at high temperatures it hardens to form a clay ceramic
.The ability to be molded then harden makes it ideal for bricks and pottery
Describe glass
.Transparent
.Can be molded when hot
.Brittle when thin
How is soda-lime glass made?
Heating a mixture of limestone, sand and sodium carbonate until it melts, when it cools it comes out as glass
How is borosilicate glass made and how is it different from soda-lime glass?
.Higher melting point
.Made in the same way as soda-lime glass, using a mixture of sand and boron trioxide
What is a composite?
.Made of one material embedded in another, fibers or fragments of a material (known as the reinforcement) are surrounded by a matrix acting as a binder
What do the properties of a composite depend on?
The properties of the material its made from
Give 4 examples of composites
Fiberglass, carbon fiber, concrete, and wood
Describe fiberglass, it’s properties and uses
.Fibers of glass embedded in a matrix made of polymer (plastic)
.Low density (like plastic)
.Very strong (like glass)
.Used for things like skis, surfboards, and boats
What things influence the properties of a polymer?
How it’s made and what it’s made from
What do the properties of poly(ethene) depend on?
.The catalyst that was used
.The reaction conditions (temperature and pressure) that it was made under
How low-density poly(ethene) is made and uses
.Moderate temperature
.High pressure
.Catalyst
.Flexible so used for bags and bottles
How high-density poly(ethene) is made and uses
.Lower temperature
.Lower pressure
.Different catalyst
.More rigid so water tanks and drain pipes
Describe thermosetting polymers
.Monomers that form crosslinks between the polymer chains, holds the chain together in a solid structure
.Don’t soften when heated
.Strong hard and rigid
Describe thermosoftening polymers
.Individual polymer chains entwined together with weak forces between the chains
.You can melt and remold these
Properties of ceramics
Insulators of heat and electricity
Brittle
Stiff
Properties of polymers
Insulators of heat and electricity
Flexible
Easily molded
Properties of metals
Malleable Good conductors of heat and electricity Ductile Shiny Stiff
How much carbon is in low carbon steel? Properties and uses
0.1% - 0.3%, easily shaped, car bodies
How much carbon is in high carbon steel? Properties and uses
0.22% - 2.5%, very hard, inflexible, blades for cutting tools, bridges
How is stainless steel made? properties and uses
Chromium added, and sometimes nickel, corrosion resistant, cutlery and containers for corrosive substancs
Bronze =
copper + tin
harder
Brass =
Copper + zinc
Malleable
Low friction
What metals are used to harden pure gold?
Zinc, copper, and silver
How many carats of gold in pure gold?
24
Properties of aluminum
Low density, soft, alloyed to make it harder for use in airplanes
What is corrosion?
Where metals react with substances in their environment and are gradually destroyed
What is the word rust used for?
The corrosion of iron and its alloys (steel)
What is rusted iron actually?
Hydrated iron(III) oxide
What is the word equation for the rusting of iron?
Iron + oxygen + water –> hydrated iron (III) oxide
What happens to the iron in rusting?
It is oxidized
Properties of rust?
Soft and crumbly so flakes off to reveal more iron to rust
Why is the corroding of aluminum not as bad as the rusting of iron?
The aluminum oxide that is formed doesn’t flake away like Hydrated iron(III) oxide and instead forms a protective layer so only the very outer bit gets corroded
How to show iron needs both water and oxygen to rust
.Boil water to remove oxygen, put in a test tube, put a nail in the tube, put oil on top to stop oxygen entering, nail won’t rust
.Put calcium chloride in a tube to remove water, put a nail in the tube, t won’t rust
.Put a little bit of water in a tube, put a nail in the tube so its half covered in water and half in the air, it will rust
3 types of barrier methods to prevent rusting
.Painting/coating with plastic - ideal for big and small and can be decorative
.Electroplating - uses electrolysis to reduce metal ions onto an iron electrode, can be used to coat the iron with a layer of a different metal that won’t be corroded away
Oiling/greasing - used when moving parts are involved, like a bike chain
What is the sacrificial method of protection?
Placing a more reactive metal, like zinc or magnesium, with the iron. Water and oxygen then react with the more reactive metal rather than the iron
What does a life cycle assessment do?
It looks at every stage of a products life to assess the impact it would have on the environment
What are the different stages to assess in an LCA?
.Getting the raw materials
.Manufacturing and packaging
.Using the product
.Product disposal
In the ‘getting raw materials’ stage what do they look at?
.How extraction can harm the local environment
.How extraction adds to pollution due to the amount of energy used
.How much energy it takes to process the raw material to get the desired material, for example, fractional distillation of crude oil
In the ‘Manufacturing and packaging’ stage what do they look at?
.How much energy the manufacturing uses
.How much pollution manufacturing causes
.Are there any waste products from manufacturing?
In the ‘Using the product’ stage what do they look at?
.If the use of the product can damage the environment - like fertilisers leaching into streams and rivers
.How long a product is used for/how many uses you get out of it
In the ‘Product disposal’ stage, what do they look at?
.If the product will take up space and pollute land/water in a landfill
.How much energy will be used to transport it to the landfill site
.Will it be incinerated and cause air pollution
Problems with LCA’s?
.Hard to quantify the effect of some pollutants
.Can be biased as not objective
.Some LCA’s called ‘selective LCA’s’ can be written to deliberately support the claims of a company, in order to give them positive advertising
What is potable water?
Water that has been treated or is naturally safe for humans to drink
How isn’t potable water pure?
Lots of dissolved substances, not just H2O molecules
What is important when making potable water?
.Levels of dissolved salts not too high
.pH between 6.5 and 8.5
.No bacteria or other microbes in it
Rainwater is fresh water, what does that mean?
Doesn’t have much dissolved in it
When it rains where does water collect?
Either surface water (lakes and rivers) or groundwater (rocks called aquifers that trap water underground)
Where does the source of water depend on?
Location
How is fresh water treated?
Filtration - first through a wire mesh to screen out large twigs then through gravel and sandbeds to filter out any solid bits
Sterilization - to kill any harmful bacteria or microbes, can be done by bubbling chlorine gas through it or using ozone or ultraviolet light
What can you do to seawater to make it fresh?
Distillation and reverse osmosis
What is reverse osmosis?
The salty water is passed through a membrane, it only allows water molecules to pass through, ions and large molecules are trapped by the membrane so won’t pass through so are separated
Why are distillation and reverse osmosis not practical for producing large quantities of fresh water?
Loads of energy so really expensive
How can you test and distill water?
.Use a pH meter to test the pH, if it’s below 6.5 then add some alkali and if it’s above 8.5 add some acid to neutralize it
.Take out two small samples of the water from the water you have, do the chlorine ion test on one and the sodium ion test on the other to see if sodium chloride is present
.Distil the water by pouring it into the distillation apparatus, heat the flash from below, the water will turn to steam and leave any undissolved salts in the flask, steam will condense back into liquid water in the condenser and be collected as it runs out
.Retest the water’s pH and if sodium chloride (salt) is present to know if it worked
Sources of wastewater
The home (baths etc), agriculture (nutrient runoffs from fields) and industrial processes (like the Haber process)
Why does wastewater need to be treated more?
To remove any organic matter, harmful microbes or harmful chemicals, it would pollute freshwater sources if not done
Where does waste water get treated?
Sewage treatment plants
Describe the process of treating wastewater
.The sewage is screened to remove large bits of material and grit
.The sewage stands in a sediment tank and undergoes sedimentation, the heavier solids sink to the bottom and produce sludge and the lighter effluent floats on the top
.The effluent in the settlement tank is removed and treated by biological aerobic digestion
.The sludge from the bottom of the settlement tank is also removed and transferred into large tanks, where it gets broken down by bacteria in anaerobic digestion
.Anaerobic digestion breaks down organic matter in the sludge, releasing methane gas in the process, this can be used as an energy source and the remaining digested waste as fertilizer
What is biological aerobic digestion?
.Air is pumped through the water to encourage the aerobic bacteria to break down any organic matter - including other microbes in the water
If the treated wastewater contains toxic substances what other stages might they have to do?
.Adding chemicals (to precipitate metals)
.UV radiation
.Using membranes
Haber process word equation
nitrogen + hydrogen ammonia (+heat)
Haber process symbol equation
N2(g) + 3H2(g) 2NH3(g) + (heat)
Where is the nitrogen obtained from? For the Haber process
The air as it is 78% nitrogen
Where is the hydrogen obtained from? For the Haber process
Reacting methane with steam to make hydrogen and carbon dioxide
Conditions needed for Haber process?
.Reactants passed over iron catalyst
.High temp (450’C)
.High pressure (200 atmospheres)
How is nothing waster in the Haber process?
Ammonia is formed as a gas, but cools in the condenser and liquifies to be removed, the unused hydrogen and nitrogen are recycled back through the reactor
What can the ammonia produced by the Haber process be used for?
Making ammonium nitrate, a very nitrogen-rich fertilizer
Why is 450’C used in the Haber process?
It’s a compromise, since the Haber process is a reversible reaction you want to make the equilibrium shift towards the ammonia, which is done with a low temperature since the forward reaction is endothermic, abut a high temperature is needed for a fast rate of reaction so 450’C is a compromise between fast RoR and shifted equilibrium
Why is 200 atmospheres used in the Haber process?
.Shifts equilibrium to ammonia side (4 reactants for 2 ammonia)
.Increases RoR
.Not too dangerous or expensive
Why is an iron catalyst used in the Haber process?
.Increases RoR, doesn’t affect yield
Why are formulated fertilizers better than manure?
.More widely available
.Easier to use
.Don’t smell
.Have just enough of each nutrient so more crops can be grown
What are the 3 main essential elements in a fertilizer?
nitrogen, phosphorus, and potassium
Why might N, P, or K not be in the soil already?
Used up by previous crops
What do fertilizers do?
.Replace missing elements/provide more of them
.Increase crop yield as they can grow faster and bigger
What do plants use nitrogen for?
Produce plant proteins
What are NPK fertilizers?
Fertilizers containing the right percentages of nitrogen (N), phosphorus (P) and potassium (K)
How is nitric acid made?
Ammonia reacted with oxygen and water
Ammonia + nitric acid –>
Ammonium nitrate
Ammonia + nitric acid symbol equation
NH3(aq) + HNO3(aq) –> NH4NO3(aq)
Why is Ammonium nitrate good for fertilizers?
Nitrogen from 2 sources
How is ammonium nitrate made in industry?
.In giant vats at high concentrations resulting in a very exothermic reaction
.The heat released is used to evaporate water from the mixture to make a very concentrated ammonium nitrate product
How is ammonium nitrate made in the lab?
.Smaller scale
.Titration
.Lower concentration of reactants, less heat produced, safer for the person to carry out
.After titration the mixture is crystallized to produce pure ammonia crystals
Why isn’t crystallization used in industry?
Too slow
What is used as a source of potassium?
Potasium chloride and potasium suphate are mined
Why can’t phosphate rock be used straight away by plants?
The phosphate salts in the rock are insoluble
How do you get soluble phosphate salts from phosphate rock?
React it with acid
Reacting phosphate rock and nitric acid produces
phosphoric acid and calcium nitrate
Reacting phosphate rock and sulfuric acid produces
Calcium sulfate and calcium phosphate (a mixture known as single superphosphate)
Reacting phosphate rock and phosphoric acid produces
Calcium phosphate (a product known as a triple superphosphate)
