Chapter 7 Flashcards
(22 cards)
formula for finding degree of UNsaturation?
CnH2n
When halogens take the place o hydrogens, what happens?
add their number to the number of H’s
What happens to the C:H ratio with O in the formula?
it doesn’t change the C:H ratio
what happens to the C:H ratio when Nitrogen is present?
it acts like “half” a carbon
Naming Alkenes?
-parent chain is longest chain containing the double bond
-ane changes to -ene(or -diene, -triene)
-number the chain so that the double bond has the lowest possible number
Where is the double bond in a ring with an alkene?
assumed to be between carbon 1 and carbon 2
How to assign Z vs E?
if high priority groups are on the same side, the name is Z and if they are on opposite side the name is E
What occurs during hydrogenation?
Alkene+H2–> Alkane
-requires a catalyst such as Pt, Pd or Ni
What occurs in a electrophilic addition reaction?
- pi bond electrons attack the electrophile
- nucleophile attacks the carbocation
What can be used to drive the hydration of alkenes?
Use H2SO4 or H3PO4
What is Markovnikov’s Rule?
the proton of an acid adds to the carbon in the double bond that already has the most H’s
What is a more general way of looking of Markovnikov’s Rule?
in an electrophilic addition to an alkene, the electrophile adds in a such a way as to form the more stable intermediate
What 5 things can be added to alkenes to form Markonvnikov’s products?
H2O, H2SO4, HCl, HBr, and HI
Addition of HX, aqueous HBr
- protonation of the double bond to yield a more stable carbocation
- Br- attacks the carbocation
What is the Hammond Postulate?
the structure of a transition state resembles the structure of the nearest stable species
Which carbocation is formed faster?
tertiary carbocation
are cis or trans alkenes more stable?
trans alkenes are more stable(because don’t have steric strain between two larger substituents on the same side of the double bond?
as an alkene has more -H substitutions, what happens to the Heats of reaction?
the delta H decreases as the carbon has more substituentes because it is more stable
What step is the slowest in an electrophilic addition reaction of an alkene?
protonation of the alkene to yield the intermediate cation
In an electrophilic addition reaction of an alkene, what is needed for the addition of water?
a strong catalysit(under arrow and says catalyst)
what does regiospecific mean?
when only one of two possible orientations of an addition occurs
