Structure and Properties - C2
- Created by: chickpeatweet
- Created on: 17-04-14 19:21
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- Structure and Properties
- Giant Ionic Structures
- Solid at room temperature
- Conduct electricity when molten or dissolved
- ions that carry charge can move freely
- High melting/boiling point
- The ionic bonds need a lot of energy to break the bonds
- Simple Molecules
- Atoms within molecule held by strong covalent bond
- Has no overall charge so do not conduct electricity or carry a charge
- intermolecular forces between molecules are weak
- Have a low melting/boiling point and a gas at room temp.
- This is the attraction between molecules
- Larger molecules like C6H14 have stronger IF. so will be liquids at room temperature
- For example: H2, Cl2
- Giant Covalent Structures
- Also called macromolecules
- Atoms held together by strong covalent bonds
- Also joined to several other atoms
- Covalent bonds need a lot of energy to break
- Very high melting and boiling point
- Example - Diamond is made of carbon atoms covalently bonded to four other carbon atoms
- This makes it very hard and transparent
- 3D structure - like a prism
- Example - Graphite (type of carbon) Covalently bonded to to three other atoms
- 2D structure made up of layers
- Carbon atoms slide so they can rub of (pencil lead)
- One electron from each atom is delocalised and can therefore conduct electricity and heat
- 2D structure made up of layers
- Fullerenes
- Large molecules formed from hexagonal rings of carbon
- Join to form cage-like shapes with different numbers of carbon atoms
- Useful as:
- Catalysts
- drug delivery into body
- Lubricants
- Large molecules formed from hexagonal rings of carbon
- Giant Metallic Structures
- Made of layers
- Layers slide over each other so object can bend or stretch
- Useful for wires, rods and sheets
- Layers slide over each other so object can bend or stretch
- Different sized atoms in alloys mean the layers cant slide
- Makes object harder
- Metals have delocalised electrons in their atoms so they are good conductors of heat and electricity
- Made of layers
- Properties of Polymers
- The properties of polymers depend on the monomers used to make them
- Changing reaction conditions can aslo change the properties of the polymer that is produced
- Whether it's high density or low density for example
- High density has a higher softening temp and is harder than low density
- Whether it's high density or low density for example
- Polymers have different properties depending on the monomer it's made of
- Polyethene softens at lower temps than ploypropene
- Thermosoftening polymers (like polyethene) become soft when heated and hard when cool, this makes them good for moulds
- Thermosetting polymers dont change shape when heated because strong covalent bonds cross-link between the polymer chains
- Chains weak - intermolecular forces break when heated and bring molecules back together when cool
- Nanoscience
- The study of small particles sized 1 - 100 nanometres
- Nano particles behave differently to the bulk materials they're made of
- Their small size gives them a large surface area + new properties
- More research needed into possible issues that might arise from increased use
- Nanoparticles are used in nanotechnology
- Selective sensors
- Very efficient catalysts
- new cosmetics like sun cream and deodrant
- If used more could get into air and bodies
- Could cause damage and so more research is being done
- Giant Ionic Structures
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