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