Pt. 2 Flashcards
Why do metals conduct heat and electricity
they have delocalised electrons that can carry a charge/heat throughout its structure
Why are metals malleable?
they have a regular structure with many layers
these layers can slide over each other
therefore metals can be bent and shaped
What are alloys and how do they make metals stronger?
made from two or more different metals
the different sized atoms distort the layers in the structure
this makes it more difficult for them to slide over each other
What do shape memory alloys do?
return to their original shape after being deformed
e.g. nitinol in braces, as the dentist can make braces that exactly fit the person
Why do polymers have different densities?
depends on the conditions under which they are made
low density and high density poly(ethene) are produced using different catalysts and conditions
Why do thermosetting polymers not melt when they are heated?
thermosoftening polymers consist of individual, tangled polymer chains
thermosetting polymers consist of polymer chains with cross-links between them so they don’t melt
What is nanoparticles?
Nanoscience refers to structures that are 1–100nm in size, of the order of a few hundred atoms
Nanoparticles show different properties to the same materials in bulk and have a high surface area to volume ratio
e.g. could be used to make sun tan creams or stronger/lighter construction materials
