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Oddishii
on FreezingBlue Flashcards.
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What are some properties of metals and alloys?
- Good conductors
- Malleable
- Requires heat treatment
- Low cost
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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
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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
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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.
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True or false: polymers are low density
True
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True or false: polymers are high density
False
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True or false: ceramics are strong under compression
True
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True or false: Ceramics are very brittle
True
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What are some properties of semiconductors?
Unique electric behavior that converts electric signals to lasers, LED, and diodes
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What are some properties of composite materials?
- Blends different materials
- Very hard
- Shock absorbs
- Low cost
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True or false: ceramics have high strength to weight ratio
False; polymers and composites do
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True or false: polymers have a high strength to weight ratio
True
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True or false: glass is amorphous
True
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True or false: glass is not amorphous
False
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What does amorphous mean?
Does not have regular arrangement of atoms
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How does temperature affect ceramics and polymers?
Ceramics and polymers melt at high temperatures, but at low temperatures, they are very brittle
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How does corrosion affect metals, ceramics, and polymers?
- Metals and ceramics disintegrate
- Polymers oxidize
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In the periodic table, where would you find carbon based polymers?
4B
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In the periodic table, where would you find metallics?
Groups 1 and 2, and transition metals
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In the periodic table, where would you find semiconductors?
4B, 2B & 6B, and transition metals
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True or false: polymers with strong Van Der Waal bonds are stiffer but brittle
True
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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