C3 Flashcards
What type of element are covalent bonds usually made up of?
non-metals
What is a macromolecule?
A giant covalent structure
Why do substances composed of larger molecules have higher melting/boiling points?
They have stronger intermolecular forces which require more energy to overcome.
List 2 properties of a giant covalent structure:
-high melting/boiling point
-insoluble
List some properties of carbon nanotubes
-Have high tensile strength- can withstand a lot of force
-High conductivity
Name two applications of fullerenes:
-Can be used to deliver drugs into the body
-Can be used as catalysts
How are metals held together in metallic bonding?
The metal ions are surrounded by delocalised electrons that hold them together through electrostatic attraction.
What gives metals their malleable and ductile properties?
The layers of atoms are able to slide over each other easily.
Why are alloys harder than pure metals?
The atoms of other elements distort the layers of the metal, causing them to become harder and less flexible
How long is one nanometre?
1 billionth of a metre, or 1*10(^-9)m
What are some potential risks of nanoparticles?
-As they are used more frequently- they may fund their way into the atmosphere and could cause harm if breathed in
-Could affect aquatic life
Why is graphite a good lubricant?
The intermolecular forces between its layers are weak, so they can slide over each other
Why does aluminium have a higher melting point than sodium?
It forms ions with a greater positive charge and has a greater sea of delocalised electrons which make the metallic bonding stronger than in sodium.
How many nanometres are in a micrometre?
1000
Name two uses of silver nanoparticles:
-Used in fridges to stop bacteria growing
-Used as an antimicrobial coating
