Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

organic chem > Lecture 4: newman, cyclos etc > Flashcards

Lecture 4: newman, cyclos etc Flashcards

You may prefer our related Brainscape-certified flashcards:
Periodic Table flashcards Chemistry 101 flashcards AP® Chemistry flashcards Organic Chemistry 101 flashcards
1
Q

true or false: 2 groups bonded by a double bond can rotate around the bond and get difference conformations

A

false, but be single

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what are conformations

A

different spacial arrangements of a molucle that are generate by rotation about single bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

true or false, you can rotate around pie bonds

A

false, only sigma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

explain the relationship between different conformations and their stability

A

diff conformations are possible but not all have the same energy (some are more stable than others)

=rotating changes the proximity of electrons to each other therefore affecting bond length and energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

explain staggered conformation

A

where the dihedral angle b/w bonds at each carbon are 180 degrees from each other and groups attached to c are as far away as possible

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

explain eclipsed formation

A

atoms bonded to carbons at each end of carbon bond are directly opposive to eeach other and dehidral angle is 0

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is the dihedral angle of staggered

A

18-

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what is the dihderal angle of escliped

A

0

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

the H-C-C-H bonds are called what

A

dehidral

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is anti conforatkon

A

staggered with didegrealk angles of 18

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is gauche conformation

A

dihedral angle of 60 betweeen H-H

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what conformation has lowest energy

A

staggered (anti)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what conformation has highest energy

A

ecliped (total)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

explain why staggered anti is the most stable

A

because there is less steric interactions
we are putting the molecuels are far as possible therefore less e e repulsion/interaction
and hyperconjuation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what is hyperconjugation

A

favourable overal between filled and unfilled sigma orbitals in stagged conformation
=occurs ehn electrons in filld bonding orbitals move partially into unoccupied anto bonding portion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

hyperconjugation is greatest in what configuration

A

staggered anti

the 2 orbitals are parallel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what is a steroisomer

A

same molecular formula and connectivity but different arrrangement of atoms in space

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what is a constitutional isomer

A

same molecular formula but diff connectivity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what is a conformational isomer

A

related to one another by BOND rotation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

true or false: cyclopronane doesnt have ring strain

A

false, it has alot

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what is angle strain

A

deviation from ideal bond angled fue to inherent constraints (rings, size)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

explain why cyclopropany is not stable in ring

A

because normally carbons of alkanes are sp3 hybridized therefore their bond angles should be around 109 but with cyclopropane, internal angles are 60 ttherefore there is alot of angle strain

=poor overalap in sp3 orbitals
=c-c bonds are weak and not as stable

23
Q

what is the most stable cylco and why

A

cyclohexeme because internal angles do not differ alot from nomral bond angle

24
Q

what conformation does cyclohexene adopt to minimize ring sdtraign

A

chair

25
Q

what are the axial protons

A

protons that point up and doen

26
Q

what are equitorial protons

A

point away laterall

27
Q

is there less steric interaction in equirotal or axial

A

equi

28
Q

but the different conformations of cyclohexane in decreasing order of stability

A

chair, twist boat, boat, half chair

29
Q

what happens to axial and equitoral protons are we change conformations

A

axial goes to equi and vice versa

30
Q

which is more stable and why: boat or chair

A

chair (less sterial interactions)

31
Q

chair conformatios with larger subs at the axial opr equitoral are more stable

A

equi because no 1,3 diaxiual intereactions

32
Q

true or fals: there are less repulsive forced in the axial methyl conformtionl

A

false, in equi

33
Q

what are egeometric/cis-trans isomers

A

they have same moculecular formula, same connectivity but different arrangement of their atoms in space due to presence of double bond

34
Q

true or false: geometric (cis trans) insomeers are also consideered stereosiomers

A

true

35
Q

cis isomers have subsitutents on same or diff side

A

same

36
Q

trans insomers have substituents or same or diff sides

A

diff

37
Q

which conformation, cis or trans, alllows for dipole moment

A

cis

38
Q

all axial subsituents are trans or cis to each other

A

trans

39
Q

what is another name for index of hydrogen deficiency

A

degree of unsaturaion

40
Q

what is IDH

A

diff in # of pairs of hydrogen attoms between compound of interest in compairson to normal alkane with same number of C

41
Q

what is a saturated hydrocarbon

A

every H is attached to an H (no rings or double bonds)

42
Q

what is an unsaturated hydrocarbon

A

C os attached to something that is not a H (double bond, rings)

43
Q

what is the general molecular formula for alkana

A

cn h2n+2

minus 2 h for every double bond or ring

44
Q

what is the formula for a cyclioc alkene

A

cnh2n-2

45
Q

what is the formula for alkene or cyclic alkane

A

cnh2n

46
Q

1 ring is how many degree of unsaturation

A

1

47
Q

1 double bond is how many degree of unsat

A

1

48
Q

2 double bonds, is how many degree unsaturation

A

2

49
Q

1 triple bond is how mnay degree unsaturation

A

2

50
Q

2 rings is how many degrees of unsaturation

A

2

51
Q

how to count IHD for halogents

A

count halogens as tho they are hydrogens

52
Q

how to count IHD for oxygen

A

ignore the oxygen atoms and calcualte IHD from remainder of the formula

53
Q

how to count IDH for nitrtogen

A

subtract one hydrogen for each nitrogen atom and ignore the nitron atoms

organic chem (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions