Carbon chemistry 2 - polymer chemistry Flashcards
How does the presence of double bonds in alkenes affect it?
means it is unsaturated
What are the rules of naming alkenes?
Choose longest double bond carbon chain
Number carbons in chain from nearest double bond
Pick carbon with lowest number to describe position of double
What are the ways to describe stereoisomers/ geometric isomers?
Trans- opposite orientations= across
Cis- same spatial orientation= on the side
How are atoms attached in stereoisomers?
all the atoms are attached to the same partners, but the partners are arranged differently in space
Is there any free rotation in stereoisomers?
No free rotation due to rigidness from carbon double bond
What does the Lewis model not explain in relation to alkenes?
Why alkenes are more reactive then alkanes
How do orbitals in alkenes form covalent bonds?
formed by the overlap of orbitals creating 3 bonds (σ-bonds)
What happens to the remaining electron after the σ-bonds form in an alkene?
The electron is in the C p orbital which over lap sideways creating a π-bond
What does the orbital bonding in alkenes actually mean the bonding is?
bond is actually a σ-bond + π-bond
Why is the π-bond susceptible to attack?
Because it is exposed
How can some aromatic molecules appear with optical isomerism?
in 2 forms which are a mirror image of each other
What will the mirror image aromatic molecule typically involve?
C atoms where 4 different atoms or groups have attached
What are the parts of the mirrored aromatic molecule called?
The carbon is the chiral centre
Mirror image is called enantiomers
What are non-superimposable molecules?
no matter how the structure is rotated, it cannot be put on top of another with all points matching
What reactions can occur to alkenes?
Combustion
Addition (C double to C single)
Oxidation
Polymerisation
How can the oxidation of alkenes be used?
Used to detect unsaturation with KMnO4 changing from purple to brown
What is polymerisation? (alkenes)
multiple addition reactions together
What is an example of polymerisation of ethene?
Ethene to polythene
What is the name for a long chain molecule?
polymer
What are polymers classified as due to their large size?
macromolecules
How can polymers be arranged?
Linear or branched
What is a copolymer?
When more than one type of monomer is involved in the synthesis reaction
What are the 3 important types of copolymer?
Block
Graft
Random
What is a block copolymer?
Contains blocks of monomers of same type
