Alkenes Flashcards
What is a sigma bond
Direct overlap of orbitals
What is a pi bond
Sideways overlap of adjacent p-orbitals
Define stereoisomers
Molecules with the same structural formula but with a different arrangement of atoms in space
What do E/Z isomerism must have
. C=C that cannot rotate
. Each C of the C=C has two different groups attached
How do you find out which one is the higher priority
The atoms with the highest Mr is the higher priority
What is a z isomer
If the high priority groups are both above or below the C=C
What is an E isomer
If the high priority groups are on opposite sides
What do cis-trans isomers must have
2 of the substituent groups are the same
Why are alkenes more reactive then alkanes
Due the relatively low bond enthalpy of the pi bond
What are the reagents, conditions, mechanism and product of the reaction hydrogenation
Reagents- alkene+ hydrogen(H2)
Conditions- Nickel catalyst, 150c
Mechanism- Addition
Product- Alkane
What are the reagents, conditions, mechanism and the product of the reaction bromination
Reagents- alkene+ bromine
Conditions- Room temp( dropwise and shake)
Mechanism- Electrophilic addition
Product- dihaloalkane
What are the reagents, conditions, mechanism and product of the reaction adding hydrogen halides
reagents- alkene+ hydrogen halide(HBr)
conditions- room temp
mechanism- electrophilic addition
Product- haloalkane
What are the reagents, conditions, mechanism and product of the reaction hydration
reagents- alkene+ steam
conditions- concentrated H3PO4 and high temperature and high pressure
Mechanism- Electrophilic addition
Product- alcohol
What do curly arrows represent
The movement of a pair of electrons
Define an electrophile
A species that accepts a pair of electrons
Define addition
2 species join together to form 1
What is the order of the most stable to least stable carbocation
Most- Tertiary
- Secondary
Least-Primary
How do you know which product will be the major product formed
The major product is formed from the most stable carbocation
Define addition polymer
Are made when many unsaturated monomers join together and the pi bond breaks
How are polymers unreactive
C-C and C-H bonds have a high bond enthalpy
Non-Polar
What are the three main ways of disposal the polymers
1) Recycling
2) Combustion
3) Organic feedstock
Describe the process of recycling polymers
1) Sorting- this is essential as recycling a mixture of different polymers renders the product unusable
2) Reclamation- the separated polymers are chopped into flakes, melted. The product is then used to make new products
Describe the process of combustion of polymers
- Used to provide energy but need to remove toxic gas( when halogenated plastics are burnt, releasing HCl)
- Toxic gas can be removed by reacting with an alkali
Describe the process of organic feedstock of polymers
- turned in to more useful organic compounds
