Module 4 Module 4 Need To Know Flashcards
What is a homologous series (3)
Exam answer
- a series of organic compounds
- with the same functional group
- and each successive member differs by a ch2 group
WHAT IS A RADICAL
A species with an UNPAIRED ELECTRON
Why does boilign point increase as alkyl chain lenght increade
Why decrease with branching
1) as chain increase, the surface contact area is increased
2) this means more and stronger London forces can be made between molecules
3) rewuireijt more energy to overcome thus higher boiling
Branching
1) increased branching reduces surface contact area between molecules
2) this results in less and weaker London forces
3) so boilign lower
Why are alkanes not reactive (2) points spec
1) c and H have similar electronegativitied thus the bond is not polar , very less ( can’t act as electrophiles )
2) c h sigma bond has high bond enthalpy so a lot of energy needed to break for reactions
Explain alkene bonding
What happens to ROTATION a due to Pi bond?
Sigma bond = head on overlap between any orbital
(ED found greatest on line connecting two nuclei)
Pi bond = side in overlap if p orbitals and ED found greatest above and below line connecting both nuclei
2) as there is Ed above and below line, pi bond RESTRICTS rotation of the carbon atoms around the double bond. This means atoms can exist in specific positions in space
Stereoisomer DEFINITON
Same general formula, structural formula but different arrangement of atoms in soace
Remember 2 conditions for Ez
Double bond
- different groups on each atom
REMEMBER WHAT IS CIS TRANS
When two GROUPS THAT ARE THE SAME ARE FOUND ON EACH CARBON (doesn’t have to be hydorgen )
Describe the reactivity of an Alkene (why) 2
More reactive than alkanes
- due to low enthakpy pi bonds (compared to sigma)
- and the fact that pi bonding increases the space available for an electron to be, more exposed, so more reactive
What is NUCLEOPHILE ELECTROPHILE DEFINITION
Nucleophile is an electron pair donator ( negative ions , lone pairs)
ELECTROPHILE is electron pair acceptors (dipoles , positive)
What’s the benefit of having polymers but the downside too
1 good 1 bad major
Making polymers for daily use very cheap, and low reactive so good for food etc
However disposing of them is very hard as they don’t degrade
What are 3 good ways to dispose and make use of polymers and why brief
(Spec)
1) recycling , involving removing toxic from PVC (less waste and made use of it )
2) usign as fuel for combustion ( free energy, saves finite resources )
3) using them as organic feedstock for production of other polymers and chemical processes ( less waste and made use of it)
Why is PVC recycling so IMPORTSNT, what would happen if pvc polymers were used as fuel for combustion
IMPORTANT SPEC POINT WAS IS MADE
PVC contains high chlorine content
When combusted, this produces HYDROGEN CHLORIDE , which is toxic and corrosive
Therefore we need to do PVC recycling to remove hcl formed during this combustion
What’s the benefit of biodegradable and photodegradable polymers
2 BENEFITS SPEC
1) bio degradable are made from biological material, so less stress on FINITE RESORUCES (oil less used)
2) alleviates the problem of disposal of polymers which was hard to dispose of
(Not toxic residue
What are the physical properties of alcohols and why compared to alkanes
- lower volatility / higher boilign point
Due to havign hydrogen bonding in alchol structure as OH is polar, means much more energy needed to overcome these binds as well as London forces, compared to just London for alkanes - high solubility
Due to hydrogen bonds (more energy released when bonding with water)
