C2.2 - How Structure Influences Properties Flashcards
What states of matter can simple molecules be?
Solids, Liquids or Gases., that have relatively low melting/boiling points.
Why do these simple molecules have low melting/boiling points?
They only have weak intermolecular fores. When these forces are over come, the substance melts/boils.
Why do substances which consist of simple molecules not conduct electricity?
They have no overall electric charge.
What is an ionic compound usually called?
A Giant Ionic Lattice.
How are the ionic bonds formed?
There are strong electrostatic forces in all directions between oppositely charged ions.
Why do these compound have high melting/boiling points?
Large amounts of energy is needed to break the many strong bonds.
In what state can ionic compounds conduct electricity?
When melted or dissolved in water, as then the ions are free to move and carry the current.
What are giant covalent structures usually called?
Macromolecules.
How are atoms in giant covalent structures linked?
By strong covalent bonds, so they also have very high melting/boiling points.
Describe the structure of Diamond:
- Made up entirey of Carbon, covalently bonded
- Each Carbon atom has 4 bonds
- Giant Covalent Structure
- Very hard, because all possible bonds are achieved, and are also strong.
Describe the structure of Graphite:
- Made up entirely of Carbon, covalently bonded.
- Each Carbon atoms bonds to three others.
- Arranged in layers
- Layers are free to slide over each other, because there are no covalent bonds between them.
- Graphite is soft and slippery, due to the weak intermolecular forces between layers.
Does Graphite conduct electricity?
Yes, because one electron from each carbon atom is delocalised, these electrons allow graphite to conduct electricity and also heat.
What can Fullerenes be used for?
- Drug delivery into the body
- Lubricants
- As Catalysts
- In nanotubes, for reinforcing material eg. in tennis rackets
How is graphite similar to metals?
It has delocalised electrons.
What is the structure of Fullerenes based on?
Hexagonal rings of carbon atoms.
Why do metals conduct heat and electricity?
They have delocalised electrons in their structure.
What are alloys made of?
Two or more different metals.
Why are alloys much harder than metals?
The different sized atoms of the metals distort the layers in the structure of the alloy, making it more difficult for them to slide over each other, making alloys harder than pure metals.
What do the properties of a polymers depend on?
What they are made from and the conditions under
which they are made. For example, low density (LD) and high density (HD) poly(ethene) are produced using different catalysts and reaction conditions.
What do thermosoftening polymers consist of?
Many individual, tangled polymer chains.
What do thermosetting polymers consist of?
Polymer chains with cross-links between them so that they do not melt when they are heated.
What is Nanoscience?
It refers to structures that are 1–100 nm in size, of the order of a few hundred atoms.
What can Nanoparticles be used for?
Due to the high surface area to volume ratio, they may lead to the development of
- new computers
- new catalysts
- new coatings
- highly selective sensors
- stronger and lighter construction materials
- new cosmetics such as sun tan creams and deodorants.
