C10 Flashcards
What are ceramics and examples?
Ceramics are non-metal solids with high melting points that arent made from carbon-based compounds.
-Clay
-Glass
How are clay ceramics made?
Clay ceramics are made by shaping wet clay and heating in a furnace.
What makes clay ceramic ideal for pottery and bricks?
Ability to be moulded when wet and harded.
How is glass made?
By heating a mixture of sand,sodium carbonate and limetsone. The molten liquid then cools and solidifies.
What is most of the glass we use called and whats it used for?
Sode-lime glass- window paines,glass jars and bottles.
What is borosilicate glass made from and whats it used for?
Borosilicate glass-made from sand and boron trioxide.
Baking and laboratory.
What has a higher melting point borosilicate glass or soda lime glass and why is that better suited to its function?
Borosilicate has a higher melting point than soda-lime glass which makes it better suited to its function where high temps are used.
What do the properties of polymers depend on?
What monomers they are made from and which conditions they are made in.
How are low dentisty and high density poly(ethene) both produced from ethene?
Low density poly(ethene) is made from ethene at a moderate temperature under a high pressure.
High density poly(ethene) is made from ethene but at a lower temperature and pressure with a catalyst.
Uses of low and high density poly(ethene)?
Low- flexible so used for bags and bottles
High-more rigid so used for water tanks and drainpipes.
What is the difference between thermosoftening and thermosetting polymers?
Polymer chains in thermosetting plastics are held together by strong crosslinks these plastics can withstand higher temps and dont melt when heated (high melting points).
Thermosoftening have weaker forces between the chains and can be melted and remoulded.
What are composites made of?
Two materials, a matrix surrounding and binding together fibres or fragments of the other material (reinforcment).
Examples of composities?
-Wood
-Concrete
-Fibreglass
-Carbon fibre
What does fibreglass consist of,properties and uses?
Fibres of glass embedded in a matrix made of polymer (plastic).
It has a low density (like plastic) but is very strong (like glass).
Used for skis,boats and surfboards.
What does carbon fibre composites consist of,properties and uses?
Also have a polymer matrix.
The reinforcements either made from long chains of carbon atoms bonded together (carbon fibres) or from carbon nanotubes.
Very strong and light- used in aersopsace and sports car manafacturing.
What is concrete made from,property and use?
Concrete is made from sand and gravel embedded in cement.
Very strong- used as building material.
What is wood a composite of?
Wood is a composite of cellulose fibres held together by an organic polymer matrix.
Properties of ceramics?
Glass and Clay ceramics (porcelain and bricks). Theyre insulators of heat and electricity,brittle (break easily) and stiff
Properties of polymers and uses?
Polymers are insulators of heat and electricity and are flexible (bent without breaking) and are easily molded.
Clothing and insulators in electrical appliances.
Properties of metals and uses?
Metals are malleable, ductile, good conductors of heat and electricity,shiny and stiff.
Electrical wire, car body-work and cutlery.
What are most metals in everyday use?
Alloys
What is bronze an alloy of and uses?
Bronze is an alloy of copper and tin.
Uses-coins,medals,statues
What is brass an alloy of + uses?
Copper and zinc.
Uses- locks,taps, door knobs
What is gold an alloy of and uses?
Gold alloy of silver,copper and zinc.
Used in jewellery.Proportion of gold measured in carats. 24 caract=100% pure gold
18 carat = 75% gold
Aluminium alloys properties and uses
Low density
Used to make aircraft
What is steel an alloy of?
Steels are alloys of iron that contain specific amounts of carbon and other metals.
What is high carbon steel and properties + uses?
High carbon steel contains a high propotion of carbon.
Strong and brittle (break easily) and used in construction industry.
What is low carbon steel,properties and uses?
Low-carbon steel has a low proportion of carbon.
Softer and more easily shaped.
Used for making car bodies.
What is Stainless steel, properties and uses?
Stainless steel is made up of iron but but also chromium and nickel.
Corrosion-resistant and hard
Used for cutlery.
What is corrosion?
Corrosion is the destruction of materials by chemical reactions with substances in the environment.
What is rusting an example of and what is necessary forr iron to rust?
Rusting is an example of corrosion. Both air (oxygen) and water are necessary for iron to rust.
How can corrosion be prevented?
Applying a coating that acts as a barrier- greasing, painting or electrplating(reduction by electrolysis).
Aluminium has an oxide coating that protects the metal from further corrosion.
What is sacrifical protection?
Putting a more reactive metal (zinc or magnesium) with the iron. Water and oxygen then react with the sacrifical metal instead of the iron.
What is galvanising?
An object can be galvanised by spraying it with a coating of zinc. The zinc layer if proective firstly but if its scratched the zinc around the site of the sracth works as a sacrifical metal.
Experiment to show that both oxygen and water are needed for iron to rust?
Putting an iron nail in a boiling tube with just water, wont rust.( water is boiled to remove oxygen and oil is used to stop air gettin in).
If you put an iron nail in a boiling tube with just air, it wont rust (calcium chloride can be used to absorb any water from the air).
Putting an iron nail in a boiling tube with oxygen and water will make it rust.
Where are natural resources from what can they be replaced by +example?
Earth,sea, air-processed to provide energy and materials- warmth,shelter,food and transport
Can be replaced by synthetic products or improved by man made processes.
Rubber (natural product- can be extracted from a tree) however man-made polymers can now replace rubber in tyres.
What do natural resouces supplemented by agriculture provide?
food,timber and clothing
fertilisers development-produce high yield of crops
Examples of finite resources
Fossil fuels,nuclear fuels(uranium,plutonium).
Minerals and metals found in ores
What is sustainable development?
Development which meets the need of current generations without comporomising the ability of future generations to meet their needs.
