Quiz 6
Unsaturated
A molecule that contains 1 or more carbon-carbon multiple bonds
hydrogenation produces
alkane
Trans-2-octene
...
halogenation addition of Cl2 or Br2 yields
1,2-dihaloalkane product
addition reaction
2 reactants add together 2 form a single product w no atoms left over
addition reaction occurs when
2 reactants add together to form a single product w no atoms left over
substitution reaction occurs when
2 reactants exchange atoms or groups to give 2 new products
substitution reactions
2 reactants exchange atoms or groups to give 2 new products
trans isomer
2 substitutents r on opposite sides of double bond
cis isomer
2 substitutents r on same side of double bond
2-methyl-propene +HBr yields
2-bromo-2-methlypropane
In a halogenation reaction of Br2 and CH2Cl2 to a trans compound, what molecule goes on to which carbon (most/least substituted). What goes away? What is the orientation of the addition.
A Br goes to the both carbons both forward or back. Double bond goes away. Meso compound.
In a halogenation reaction of Br2 and CH2Cl2 to a cis compound, what molecule goes on to which carbon (most/least substituted). What goes away? What is the orientation of the addition.
A Br goes to the both carbons one forward one back. Double bond goes away. Anti stereochemistry and creates a racemic mixture (enantiomers).A halogen for each C , break double bond
Saturated
A molecule in which each carbon atom has the maximum number of single bonds possible(4)
hydrogenation addition
An H for each C , break double bond Addition of H2 to alkene; decreases number of unsaturated C-C bonds
In a Hydration reaction of H3O+ to a compound, what molecule goes on to which carbon (most/least substituted). What goes away? What is the orientation of the addition
An alcohol group goes to the most substituted carbon, hydrogen to the least. Double bond goes away. Markovnikov additionH to the one with the most H and OH to the other C , break double bond
Resonance
Aromatic compounds exhibit this; allows 4 the delocalization of electrons by spreading electron density over entire molecule; bc of this delocalized electrons r less reactive than those found in a normal alkene or alkyne
In a hydrohalogenation reaction of HBr to compound, what molecule goes on to which carbon (most/least substituted).What goes away? What is the orientation of the addition?
Br goes on to the most substituted carbon. The double bond goes away. Markovnikov addition.
CH2=CHCH2CH2CH3 cis trans possible?
C1 has 2 Hs attached so not possible
In a hydrohalogenation reaction of HCl to a compound, what molecule goes on to which carbon (most/least substituted). What goes away? What is the orientation of the addition.
Cl goes on the most substituted carbon. Double bond goes away. Markovnikov addition.H to the one with the most H and halogen to the other C , break double bond
Aromatic compounds structure
Contain 6 membered benzene like rings and usually written w 3 double bonds; equal bonding bw neighboring carbon atoms in benzene rings bc the double bond electrons r symmetrically spread around entire ring
Energy needed to break old bonds before new bonds can form (endothermic)
E
Alkenes display cis trans isomerism when
Each double bond carbon atom has diff substitutes
What requirement must b met for alkene to show cis trans isomerism
Each double bond carbon must b bonded to 2 different groups
minor product
H bonds to double bond carbon w less H atoms to form this product
major product
H bonds to double bond carbon with more H atoms
Properties of alkenes and alkynes
Influenced by weak London dispersion forces, bonds r nonpolar those w 1-4 carbon atoms r gases at room temperature, boiling pts inc w size of molecules
More properties of alkenes and alkynes
Insoluble in water soluble in nonpolar organic solvents, less dense than water, flammable non toxic, chemically reactive at the multiple bond
hydration (addition of H2O; H2SO4 or HgSO4)
Mark's rule is followed, H bonds to the less substituted C, -OH bonds to the more substituted C; then the unstable enol rearranges into a carbonyl (C=O) group
Resonance
Phenomenon where true structure of a molecule is an average among 2 or more conventional Lewis structures that differ only in the placement of double bonds
elimination reaction occurs when
a single reactant breaks into 2 products forming an alkene or alkyne in the process
rearrangement reactions occur when
a single reactant undergoes a reorganization of bonds and atoms to yield a single isomeric product
4 organic reactions
addition elimination reaarangement substitution
hydration produces
alcohol
hydrohalogenation addition of HBr and HCl yields
alkyl halide product
hydration addition of water yields
an alcohol product
hydrogenation addition of hydrogen yields
an alkane product (single bond)
cyclohexene
aromatic ring with CH3
CH3CH=CHCHCH3 I CH3 cis trans possible?
c-2 has methyl and H c-3 has H and CH(CH3)2 both Cs have 2 diff grps so cis trans possible
saturated molecules
contains only tetravalent carbon atoms and no double or triple bonds
cycloalkenes
cyclic hydrocarbons that contain carbon-carbon double bonds
alkenes display cis-trans isomerization when
each double bond carbon atom has different substituents
n bond=
electron density above and below plane of 2 nuclei
@bond=
electrons density bw the 2 nuclei
ethylene
flat molecule 120
unsaturated molecules
have fewer hydrogens than corresponding alkanes-indicates presence of double or triple bonds
alkenes symmetrically substituted
if each carbon of the double bond has the same number of hydrogens directly attached to ea carbon
acetylene
linear molecule 180
CH3CH=CHCH3 is cis trans isomerization possible
look at the group attached to each C of the double bond, each C must be bonded to 2 different groups in 2-butene there is a methyl and an H=2 diff grps
2 resonance structures benzene
lower one best way to indicate inc both resonance structure and show actual electron distribution in aromatic ring
catalyst works by
lowering the energy of activation E by providing a diff mechanism, a diff pathway from reactants to products
alkanes are saturated or unsaturated
saturated
propane
saturated
elimination reaction
single reactant breaks into 2 products forming alkene or alkyne
rearrangement reactions
single reactant undergoes reorganization of bonds and atoms to yield a single isomeric product
catalyst
speeds up a reaction without being consumed
ethane shape
tetrahedral 109.5
halogenation
the addition of Cl2 or Br2 to a mulitple bond to give a dihalide product
hydrogenation
the addition of H2 to a multiple bond to give a saturated product
hydration
the addition of water to a multiplke bond to give an alcohol product
C4H8 isomers
there are 4
CH3CH2C=CHCH2Cl I CH3 cis trans possible?
there r 2 diff grps however cis trans nomenclature only used when ea C of double bond is bonded to H
alkenes and alkynes are unsaturated or saturated
unsaturated
propene
unsaturated
propyne
unsaturated
Markovnikov rule
when an unsymmetrical addition reagent reacts w an unsymmetrical alkene the doubly bonded carbon with the greater number of hydrogen atoms directly bonded ends up with additional H