Allotropes of Carbon Flashcards
What is an allotrope?
Allotrope: Different form of the same element.
What kind of bond do carbon atoms form?
How many can it form?
4 Covalent bonds
Explain the bonds in diamond.
- Diamond has a giant covalent structure.
- Each carbon bonds to 4 carbon atoms by covalent bonds.
- There are no delocalised electrons because all of them are bonded.
What are the 3 properties of diamond?
- Hard
- High melting and boiling point
- Can’t conduct electricity
What are the uses of diamond?
- Jewelery
- Drills because it is hard
Explain the bonds in graphite.
- Graphite forms a giant covalent structure
- Each carbon is bonded to 3 carbon atoms by covalent bonds.
- Forms layers of hexagonal rings.
- Each carbon atom has a “spare electron.”
- All spare electrons form “electron cloud” of delocalised electrons.
- Layers can slide easily from delocalised electrons
Explain why graphite is soft and slippery.
- Aranged in layers w/ no strong covalent bonds.
- The delocalised electrons creates weak force of attraction (keeps structure together.)
- So, layers slide easily.
What are 3 the properties of graphite?
- High melting + boiling point.
- Very soft and slippery
- Good conductor of heat and electricity because of delocalised electrons.
What are the uses of graphite?
- Used for pencils (layers slide easily)
- Lubricants
Explain why graphene is strong.
- Has 3 strong covalent bonds
- Giant covalent structure: loads of them.
- Require a lot of energy to break.
What is graphene’s bonding, properties, uses?
- Graphene is a single layer of graphite.
- Good conductor of electricity
- Uses: Electronics, composites *(strong + lightweight) *
What are fullerene’s bondings and properties?
- A graphene layer, wrapped to make hollow tube.
- Hexagonal rings–> could contain 5/7 atoms.
- Buckminsterfullerene (C₆₀) - spherical shape.
- Carbon nanotubes are cylindrical fullerenes.
- Have delocalised electrons so can conduct electricity.
What are giant covalent structures?
- Large structures made of non- metals bonded covalently.
Explain why Giant covalent molecules are always solid at room temp.
- They have many strong covalent bonds
- High melting + boiling point
Explain why diamond is hard.
(2 points)
- Have 4 strong covalent bonds
- Giant covalent structure: have loads of them.
What is the bonding in silicon dioxide?
- Each silicon is bonded to 4 oxygens.
- Each oxygen is bonded to 2 silicons
(IN GIANT COVALENT STRUCTURE FORM)
Explain why silicon dioxide has a high melting point.
- Has many strong, covalent bonds
- Require a lot of energy to break.
Give 2 uses for silicon dioxide?
- Used in bags to absorb moisture
- Component of glass
What are the uses of fullerenes?
- Delivering drugs to SPECIFIC places in the body.
- Lubricants (can roll around)
- Catalysts (large surface area to volume ratio.)
Why are nanotubes good conductors?
- Delocalised electrons can move up and down hollow tube.
What can carbon nanotubes be used in because they have a high tensile strength?
- Tennis rackets.
What are 2 properties of carbon nanotubes?
1.) High tensile strength
2.) Good conductors of heat + electricity.
Why can fullerenes be used in lubricators?
- They can roll so spread around.
Q.)
Silicon dioxide has a very high melting point. Other substances are added to silicon dioxide to make glass. Why does glass melt at a lower temperature?
- The impurities distrupt the lattice structure.
Why do buckerminster fullerenes have low melting and boiling points?
- Weak intermolecular forces between the fullerene balls.
If graphite has weak intermolecular forces, why does it have a high melting and boiling point?
- Has many of these intermolecular forces: giant covalent sturcture.
- Many covalent bonds also
Suggest why buckerminster fullerene is a good lubricant.
- Spherical
- Can roll
As well as fullerenes being made of hexagonal rings what else can they be made up of (carbon atom number)?
- 5 or 7 carbon atoms
What does high length to diameter ratio mean?
- Cyliandrical fullerenes and carbon nanotubes are very long even though they may be having a small diameter. creates low weight.
Q.)
Graphite is softer than diamond.
Explain why.
- Graphite has layers that can easily slide.
- Because there are weak intermolecular forces between the layers.
- In Diamond, Each carbon atom is bonded to 4 others by covalent bonds.
- So diamond is rigid no layers can slide
How is graphite similar to metals?
- Graphite is similar to metals because it has delocalised electrons.
