Organic Chemistry Ch. 7 study guide

Organic Chemistry Ch. 7 study guide
Which of the following statements best describes the relative bond dissociation energies
of the sigma
and pi bonds present in the carbon-carbon double bond of an alkene?
A) sigma > pi
B) pi > sigma
C) sigma = pi
D) cannot be estimated - ✔Correct answer: A Section: 7.1


The carbon-carbon bond length in ethylene is ________ than the carbon-carbon bond
length in
ethane, and the HCH bond angle in ethylene is ________ the HCH bond angle in
ethane
A) shorter; smaller than
B) shorter; larger than
C) longer; smaller than
D) longer; larger than
E) longer; the same as - ✔Correct answer: B Section: 7.2


Carbon-carbon single bonds tend to be ________ and ________ than carbon-carbon
double bonds.
A) shorter, stronger
B) longer, stronger
C) shorter, weaker
D) longer, weaker - ✔Correct answer: D Section: 7.2


Which of the following best approximates the CCC bond angle of propene?
A) 90°
B) 109°
C) 120°
D) 150°

,Organic Chemistry Ch. 7 study guide
E) 180° - ✔Correct answer: C Section: 7.2


Circle all atoms that are coplanar in the molecule below. - Answer- Section: 7.2


Draw the line energy orbital diagram for the outer shell of an sp2 hybridized carbon
atom and explain how a carbon/carbon double is formed. - Answer- If we follow Hund's
rule and fill each orbital with one electron and then promote one to the lone atomic p
orbital, there are single electrons in the three sp hybrid orbitals that can form sigma
overlaps with 2-H orbitals and one other sp2 hybridized carbon orbital. The atomic p
orbital with one electron can then form a pi bond by a side to side overlap with the other
p orbital from the other sp2 hybridized carbon atom.


Section: 7.2


Why is rotation about the carbon-carbon double bond in alkenes prohibited while
relatively free rotation can occur about the carbon-carbon single bond in alkanes? - ✔
Correct answer: Rotation about the CC single bond in alkanes can occur without
breaking the bond or disrupting the orbital overlap. For rotation to occur about a CC, the
π bond would have to be broken since the p orbital overlap from which the bond is
formed is disrupted by rotation.


Section: 7.2


What two atomic orbitals or hybrid atomic orbitals overlap to form the CH bond in
ethylene?
A) C sp3 + H s
B) C sp2 + H s
C) C sp + H s
D) C p+H s - ✔Correct answer: B Section: 7.2

, Organic Chemistry Ch. 7 study guide
What two atomic orbitals or hybrid atomic orbitals overlap to form the CC σ bond in
ethylene?
A) C sp3 + C sp3
B) C sp3 + C sp2
C) C sp2 + C sp2
D) C sp3 + C p
E) C sp2 + C p - ✔Correct answer: C Section: 7.2


What two atomic orbitals or hybrid atomic orbitals overlap to form the CC π bond in
ethylene?
A) C sp3 + C sp3
B) C sp3 + C sp2
C) C sp2 + C sp2
D) C sp2 + C p
E) C p + C p - ✔Correct answer: E Section: 7.2


Consider molecules with the formula C10H16. Which of the following structural features
are not possible within this set of molecules?
A) 2 triple bonds
B) 1 ring and 1 triple bond
C) 2 rings and 1 double bond
D) 2 double bonds and 1 ring
E) 3 double bonds - ✔Correct answer: A Section: 7.3


How many elements of unsaturation are implied by the molecular formula C6H12?
A) 0
B) 1
C) 2
D) 3
E) 4 - ✔Correct answer: B Section: 7.3