Chemistry 10- using resources

Ceramics

Non-metal solids with high boiling points not made from carbon-based compounds- eg clay or glass ceramics

Soda-lime glass

Made from heating a mixture of limestone, sand & sodium carbonate

Borosilicate glass

Made from sand and boron trioxide, higher boiling point than soda lime glass

Compostite

Made from one material (reinforcer) embedded in another material (matrix)

Thermosoftening vs thermosetting polymers

Thermosoftening melt when heated, thermosetting do not

Structure of thermosoftening polymers

Polymer chains held together by weak intermolecular forces

Structure of thermosetting polymers

Polymer chains held together by strong covalent bonds

Why doesn’t aluminium rust

It forms a protective layer of aluminium oxide to prevent further corrosion

Barrier method to prevent rusting

Coat the iron in something to prevent it from reacting with oxygen and water

Sacrificial method to prevent rusting

Attach a more reactive metal that oxidises instead of the iron

Electroplating

A barrier method that involves electrolysis to coat iron with another metal

Galvinisation

Coating iron with a thin layer of zinc to prevent air from reaching it (barrier method)- if the zinc is scratched through it protects the iron by corroding first (sacrificial method)

Potable water

Water that is safe to drink

Freshwater treatment

-Water is passed through a wire mesh to remove large particles
-Next it is passed through a bed of sand and gravel to remove smaller particles
-The water is sterilised to kill microorganisms- either by bubbling chlorine gas through it, exposing it to ozone or exposing it to UV radiation

Treatment of sewage

-Sewage is passed through grates and meshes to remove anything large (screening)
-Sewage is left to sit in a settlement tank so large particles sink and smaller particles rise as sludge (sedimentation)
-Air is pumped through to supply bacteria with oxygen for aerobic digestion
-The sludge is sealed to allow anaerobic respiration

Haber process word equation

Nitrogen + Hydrogen —> Ammonia

Haber process description

-Nitrogen (from air) & hydrogen (from natural gas) are pumped through pipes
-Pressure is increased to 200 atmospheres
-Pressurised gases are heated to 450°C and passed through a tank containing an iron catalyst
-Reaction mixture is cooled so ammonia liquefies and can be removed
-Unreacted nitrogen and hydrogen are recycled

Formulation

A mixture made from a specific ratio of chemicals to ensure the product has the required properties