Using Resources

• Ceramics are non-metal solids that have high melting points and are not made from carbon-based compounds.
• Clay is a soft material when dug up and can be moulded into different shapes.

  When clay is fired at high temperatures, it hardens to form a clay ceramic.

  Clay is ideal for pottery and bricks.
• Glass is transparent and can be moulded when hot and brittle when thin.

  Most glass is soda-lime glass, made by heating a mixture of limestone, sand and sodium carbonate until it melts.

  Borosilicate glass has a higher melting point than soda-lime.

  It is made the same was as soda-lime glass, using a mixture of sand and boron trioxide.
• Composites are made of one material in another.

  Fibres or fragments act as the reinforcement.

  The matrix surrounds the reinforcement and acts as a binder.

  The properties of a composite depend on the properties its made from.
• Fibreglass consists of fibres of glass embedded in a matrix made of plastic.

  It has low density but is very strong.

  Used for skis, surfboards and boats.
• Carbon fibre composites have a polymer matrix.

  The reinforcement is either large chains of carbon atoms bonded together or carbon nanotubes.

  Very strong and light.

  Used in aerospace and sports car manufacturing.
• Concrete is made from aggregate (any material made from fragments-usually sand and gravel) embedded in cement.

  It is very strong.

  Used as a building material.
• Wood is a natural composite of cellulose fibres held together by an organic polymer matrix.
• Low density poly(ethene) is made at a moderate temperature and high pressure.

  It is flexible and is used for bags and bottles.

  High density poly(ethene) is made from ethene at a lower temperature and pressure with a catalyst.

  It is more rigid and is used for water tanks and drainpipes.
• Thermosetting polymers contain monomers that form crosslinks between intertwined polymer chains, holding the chains together in a solid structure.

  These polymers do not soften when heated.

  They are strong, hard and rigid.
• Thermosoftening polymers contain individual polymer chains entwined together with weak forces between the chains. They do not have cross-links.

  They can be melted and remoulded.
• Cermaics are insulators of eat and electricity.

  They are brittle and stiff.
• Polymers are insulators of heat and electricity.

  They can be flexible and easily moulded.

  Many applications such as clothing and electrical insulators.
• Properties of composites depends on the matrix/binder and the reinforcement used to make them.
• Metals are malleable, good conductors of electricity and ductile.

  They are also shiny and stiff.

  Used in electrical wires, car bodywork and cutlery.
• The regular structure of pure metals makes them soft.

  Alloys are made by adding another element to the metal, this disrupts the structure, making alloys harder than pure metals.

  Alloys of iron called steels are often used instead of pure iron.

  Steels are made by adding small amounts of carbon and even other metals to pure iron.
• Low carbon steel (0.1%-0.3%)- Easily shaped. Used in car bodies.

  High Carbon Steel (0.22%-2.5%)- Very hard, inflexible. Blades for cutting tools, bridges.

  Stainless Steel (chromium added)- Corrosion resistant. Cutlery, containers for corrosive substances.
• Bronze = Copper + Tin.

  Harder than Copper.

  Used to make metals, decorative ornaments and statues.
• Brass = Copper + Zinc.

  Brass is more malleable than bronze and can be used in situations where lower friction is required, such as in water taps and door fittings.
• Gold alloys are used to make jewellery.

  Pure gold is very soft.

  Pure gold is 24 carat.

  18 carat gold means 18/24 parts of the allow is pure gold, it is 75% pure gold.
• Aluminium has a low density.

  Pure aluminium is too soft for making aeroplanes so it is alloyed with small amounts of other metals to make it stronger.
• To rust, iron needs to be in contact with oxygen and water.

  The rust formed is called hydrated iron(III) oxide.
• Corrosion only happens on the surface of a material, when its exposed to air.
• Rust is a soft, crumbly solid that flakes off and leaves more iron available to rust again.

  Eventually, all the iron corrodes even if it was not on the suface.
• Aluminium corrodes when exposed to air.

  Things made from aluminium are not completely destroyed when exposed to the air.

  Aluminium oxide that forms does not flake away and forms a nice, protective layer that sticks firmly to the aluminium below and stops any further reaction.
• You can prove that water/air alone is not enough for rusting.

  An iron nail in a boiling tube with water will not rust.

  An iron nail in a boiling tube with only air. Calcium chloride or another drying agent absorbs any water from the air.

  In a boiling tube with water and air, the iron will rust.
• You can prevent rusting by creating a barrier to keep out water and oxygen.

  Painting and coating with plastic.

  Electroplating- Using electrolysis to reduce metal ions onto an iron electrode and coat the iron with a layer of a different metal that will not be corroded away.

  Oiling and Greasing are used when moving parts are involved.
• Rusting can be prevented using the sacrificial method.

  This involves placing a more reactive metal with the iron so water and oxygen react with the sacrificial metal instead of with the iron.
• Natural resources form without human input.

  Some of these natural resources can be replaced by synthetic products or improved upon by man-made processes.

  Agriculture provides conditions where natural resources can be enhanced for our needs.

  Some natural resources are finite.
• Renewable resources reform at a similar rate, or faster, than we use them.

  Finite resources are not formed as quickly as we use them

  Many finite resources undergo man-made processes to provide fuels and materials necessary for modern life.
• Many modern materials are made from raw, finite resources.

  People have to balance the social, economic and environmental effects of extracting new resources.
• Sustainable development is an approach to development that takes into account the needs of the present society without damaging the lives of future generations.

  It is unsustainable to carry on using finite resources.

  Extracting resources and processing the resources can be unsustainable too.

  If people reduce how much of a finite resource they use, that resource is likely to last longer.
• Chemists can develop and adapt processes that use low amounts of finite resources and reduce damage to the environment.

  Chemists have developed catalysts which reduce the amount of energy required for certain industrial processes.
• Copper is a finite resource.

  One way to improve its sustainability is by extracting it from low-grade ores.

  It can be extracted by bioleaching and phytomining.

  New methods of extraction have a much smaller environmental impact than traditional methods but are slow.
• Bioleaching

  Bacteria are used to convert copper compounds in the ore into soluble copper compounds, separating copper from the ore in the process.

  The leachate (the solution produced by the process) contains copper ions which can be extracted by electrolysis or displacement.
• Phytomining

  Growing plants in soil that contains copper.

  The plants cannot use or get rid of the copper so it builds up in the leaves.

  The plants can be harvested, dried and burned in a furnace.

  The ash contains soluble copper compounds, from which copper can be extracted by electrolysis or displacement using scrap iron.
• Mining and extracting metals takes lots of energy.

  Recycling takes a lot less energy and conserves the finite amount of each metal in the earth as well as decreasing landfill.
• Metals are recycled by melting them and casting them into the shape of the new product
• Glass bottles can be reused without reshaping.

  Other forms of glass cannot be reused so are recycled.

  Glass is separated by colour and chemical composition before being recycled.

  Glass is crushed and reshaped for use in glass products like bottles and jars.
• Life Cycle Assessments show total environment costs.

  They show 4 stages:

  Raw Materials

  Manufacturing and Packaging

  Using the product

  Product Disposal