chapter 14 - alkenes Flashcards
What is the definition of structural isomerism
Molecules with the same molecular formula but a different structural formula.
What is the definition of stereo isomerism
Molecules with the same molecular and structural formulas but a different arrangement of the items in space
How does stereo E-Z isomerism form
The double carbon carbon bond has a restricted rotation of each carbon and this gives rise to geometric isomerism
What is E-isomerism
When the priority group is not on the same side
what is Z-isomerism
When the priority group is on the same side (Z same) zame
What is the definition of a position isomer
It has the same molecular formula but a different position of the functional group
What is the definition of a chain Isomer
It has the same molecular Formula but a different arrangement of the carbon chain
What is functional group isomerism
It has the same molecular formula but a different functional group
What is a sigma bond
A sigma bond Is where there are electrons between the two carbon atoms
what is a pi bond
A covalent bond where electrons are above and below the plane of the 6 central atoms. formed from an overlap of p orbitals on the C atoms.
How do you classify Cabocations
tertiary carbocations will have 3 R groups
secondary carbocations will have 2 R groups
a primary carbocation will have 1 R group
which carbocation is the most stable
tertiary is the most
secondary
primary is the least
why does having more R groups make a carbocation more stable?
R groups can donate electron density onto the positive carbon. making the cation more stable
where is the major product formed from in electrophillic addition
from the most stable carbocation
Where do the arrows go in an electrophilic addition mechanism (not sulfuric acid)
from the double bond onto the H or more + element.
from the middle of the H-Br bond for example onto the Br
from the middle of the lone pair on the bromine onto the most stable carbocation.
where do the arrows go in electrophillic addition of H2SO4(strong acid)
draw it as H-OSO3H
double bond to the H on H-OSO3H
from the middle of that bond onto the OSO3H
from the middle of the lone pair of OSO3H to the positive carbon.
to name this molecule, you would name it as propyl/butyl hydrogen sulfate
Where do the arrows go in the electrophilic addition reaction with water (H2O)
reagent( strong acid, H2SO4 or H3PO4 )
from the double bond to a single hydrogen (H+)
from the lone pair on water to the positive carbon (carbocation)
from the O-H bond onto the positive O
hydrogen (H+) acts as a catalyst in this reaction
naming alkenes
if there are two double bonds. you have to state where each double bond is. eg hexA-2,4-DIene
hydrogenation/reduction mechanism. H2
conditions - Nickel, 150°C [NI]
eg. CH2=CH2 + H2 = CH3CH3
hydration mechanism H2O
conditions. 65atm, 300°C, concentrated H3PO4, phosphoric acid
CH2=CH2 + H2O = CH3CH2OH
Industrial method for making ethanol
Addition polymerization reaction
Conditions- Organic peroxide initiator or other catalyst
eg CH2=CH2 = broken double bond and square brackets with an n in the bottom right corner.
Two forms are made [LDPE] low density polyethene, and [HDPE] high density polyethene
how can alkenes contain permanent dipole dipole forces
if they are a Z isomer. electrons can pile up on one side of the molecule creating a dipole. slightly delta negative region and a slightly delta positive region
