Making our resources

• What happens to iron when it oxidizes?

  It forms rust and eventually weakens
• What is rusting?

  It is when iron reacts with oxygen and water
• What is the chemical formula for hydrated iron(III) oxide?

  Fe₂O₃·nH₂O
• What does rust look like?

  Soft, crumbly flakes on the surface
• How can rusting be prevented?

  By using grease, paint, or plastic coating
• What is sacrificial protection?

  A more reactive metal protects iron from corrosion
• What is galvanizing?

  Coating iron with zinc for protection
• How does galvanizing work?

  Zinc acts as a sacrificial anode to prevent rust
• What is the purpose of electroplating?

  To coat a metal surface with another metal
• Why are alloys stronger than pure metals?

  Different atom sizes disrupt regular arrangements
• What is steel an alloy of?

  Iron and carbon
• What is brass made of?

  Copper and zinc
• What is wrought iron mixed with?

  0.08% carbon
• What are the properties of stainless steel?

  Contains chromium to resist corrosion
• What happens when the chromium layer of stainless steel is scratched?

  Chromium below reacts to replace the layer
• What are the properties of polymers?

  Can be thermosoftening or thermosetting
• What is the difference between thermosoftening and thermosetting polymers?

  Thermosoftening melts; thermosetting does not
• What happens to thermosoftening polymers when heated?

  They melt and can be reshaped
• What are the properties of thermosetting polymers?

  They have strong covalent cross-links
• What is a composite material?

  Made of two or more different materials
• What is meant by reinforcement in composites?

  Material that strengthens the composite structure
• How is fiberglass formed?

  Fine threads of glass embedded in resin
• What are advanced composites?

  Composites using carbon fibers or nanotubes
• What is the main component of glass?

  Silica (sand)
• What is borosilicate glass used for?

  It is resistant to thermal shock
• What happens to clay when heated in a kiln?

  It hardens and forms strong bonds
• Why are ceramics brittle?

  They cannot deform easily under stress
• What is the role of catalysts in polymer formation?

  They help form high-density polyethylene
• What is the difference between LDPE and HDPE?

  LDPE has branched chains; HDPE has straight chains
• What happens to thermosetting polymers when heated?

  They burn or char instead of melting
• What is thermohardening?

  Monomers form strong covalent bonds preventing softening
• What is the main use of tungsten steel?

  Drill bits
• What is the purpose of using nickel in steel?

  To improve strength and corrosion resistance
• What is the main property of low-density polyethylene?

  It is flexible and lightweight
• How does the structure of pure metals differ from alloys?

  Pure metals have layers that slide easily
• What is the significance of the outer shell of electrons in metals?

  It allows atoms to slide over each other
• What is the main use of aluminum alloys?

  Aircraft and vehicle manufacturing
• What is the role of carbon in steel?

  It increases strength and hardness
• What is the main property of high-carbon steel?

  Strong but brittle
• What is the purpose of using ceramics in construction?

  They are resistant to chemical attacks