CHEM 1100 - Material Science

  1. What are some properties of metals and alloys?
    • Good conductors
    • Malleable
    • Requires heat treatment
    • Low cost
  2. What are some properties of ceramics and glasses?
    • Optically transparent
    • Strong hardness, but very brittle
    • Thermally insulating
    • High melting point
    • Do not conduct heat well
    • Can be used as a barrier for coating in metals
    • Stores charge
    • Has a refractive index
  3. What are some properties of polymers?
    • Organic
    • Repeating units covalently bonded to one another 
    • Low density, high resistance to corrosion
    • Plastic
    • Low strength
    • Strength to weight ratio high
    • Not good for high temps
    • Thin, flexible 
    • Electrically insulating
  4. What is the difference between thermoplastic polymers vs thermosetting?
    • Thermoplastic are not rigidly connected, therefore ductile
    • Thermosetting plastics are not as rigidly connected, so they are brittle, but stronger.
  5. True or false: polymers are low density
  6. True or false: polymers are high density
  7. True or false: ceramics are strong under compression
  8. True or false: Ceramics are very brittle
  9. What are some properties of semiconductors?
    Unique electric behavior that converts electric signals to lasers, LED, and diodes
  10. What are some properties of composite materials?
    • Blends different materials
    • Very hard
    • Shock absorbs
    • Low cost
  11. True or false: ceramics have high strength to weight ratio
    False; polymers and composites do
  12. True or false: polymers have a high strength to weight ratio
  13. True or false: glass is amorphous
  14. True or false: glass is not amorphous
  15. What does amorphous mean?
    Does not have regular arrangement of atoms
  16. How does temperature affect ceramics and polymers?
    Ceramics and polymers melt at high temperatures, but at low temperatures, they are very brittle
  17. How does corrosion affect metals, ceramics, and polymers?
    • Metals and ceramics disintegrate
    • Polymers oxidize
  18. In the periodic table, where would you find carbon based polymers?
  19. In the periodic table, where would you find metallics?
    Groups 1 and 2, and transition metals
  20. In the periodic table, where would you find semiconductors?
    4B, 2B & 6B, and transition metals
  21. True or false: polymers with strong Van Der Waal bonds are stiffer but brittle
  22. What are the differences between diamond and graphite?
    • Diamonds are arranged in an array, whereas graphite is in layers 
    • In diamonds, all four C are covalently bonded to each other. In graphite, only three.
    • Graphite is electrically conductive; diamond insulates
  23. How do light optical microscopes work? Why aren't they good?
    • Uses visible light as a probe to magnify the image. 
    • Not good because smallest they can go is ten to the negative six
  24. How do x-rays work?
    • Sends electromagnetic radiation that penetrates thru matter to find the arrangement of crystals using a diffractometer to measure space, diffraction peaks, and planes
    • Can also measure chemical structure; xrays can be used to excite electrons
  25. How does a transmission electron microscope work?
    • Uses high energy electrons, accelerated with a voltage from 100 000 - 500 000 V, and into a small beam. 
    • Gets directed at a small film. The high energy electrons penetrate film. If there are cracks n shit, electrons split
  26. How does a scanning electron microscope work?
    • Similar to a transmission electron microscope, it creates a beam across the surface 
    • From the primary beam, the secondary beam would scan the surface for e
    • Speciman must conduct e
  27. How does a scanning tunnel microscope work?
    • An atomically sharp probe is scanned over a surface w space in between
    • Current is between the gap
    • Image produced is from the vertical motion of the probe
  28. How does an atomic force microscope work?
    • An atomically sharp probe is scanned over a surface w space in between
    • Moves up and down
    • Different heights show different colours
    • Measures a wide variety of shit
  29. How does a mass spectrometer work?
    • Gas molecules are converted into positive ions 
    • Magnetic field hits and sorts the ions by mass
    • Measures chosen gas - can look at partial pressure of ions in a gas
  30. Name a fuel additive and why additives are added
    Example: Ethanol, MTBE

    • 1) Improves engine performance by increasing octane rating to increase compressibility before it ignites
    • 2) Add oxygen for a more complete combustion
  31. Compare and contrast metallic and covalent bonds in terms of ductility (ability to bend into shape)
    Metallic bonds are non directional. Non directionality and shielding ions by electron cloud leads to higher ductilities.

    Covalent bonds are highly directional and this limits ductility making it diffiicult for atoms to slip past one another, therefore not very ductile
Card Set
CHEM 1100 - Material Science