Conformations

Question 1

Are bonds free to rotate?

Answer 1

Yes and its free, heat in the atmosphere is enough

Question 2

What is staggered conformation?

Answer 2

When atoms are positioned far apart

Question 3

What is eclipsed conformation?

Answer 3

When atoms are positions so they look like they overlap.

Question 4

What is more stable staggered or eclipsed conformation?

Answer 4

Staggered since atoms are further apart electrons face less repulsion

Question 5

What does a wedged line mean>

Answer 5

Coming towards you

Question 6

What does a dashed line mean?

Answer 6

Going away from you

Question 7

What is the anti conformation?

Answer 7

When atoms are positioned as far apart as posible

Question 8

What Is the gauche conformation?

Answer 8

When atoms are staggered but not as staggered as anti

Question 9

What does adding a bulky group do to movement of a molecule about a bond?

Answer 9

It hinders movement by increasing steric hinderance. The energy needed to rotate this bond is increased

Question 10

What’s more rigid an alkane or a cycloalkane?

Answer 10

Cycloalkane as bonds don’t rotate

Question 11

what are the most common rings?

Answer 11

5 and 6 membered since they don’t have as much angle strain as other rings that deviate more from the preferred 109degrees

Question 12

What his higher energy linear alkane or equivalent cycloalkane

Answer 12

the cycloalkane since it faces ring strain, unless its 6 membered

Question 13

What effect increases energy of cycloalkanes above 6 membered rings

Answer 13

steric hinderance

Question 14

What is angle strain? (Cycloalkanes)

Answer 14

When the angle deviates from the desired 109.5 degrees of an sp3 hybridised carbon

Question 15

What is torsional strain? (Cycloalkanes)

Answer 15

The molecule trying to rotate to stop eclipsing making a strain on the bond (the molecule puckers)

Question 16

What is steric strain? (Cycloalkanes)

Answer 16

Methyl groups forced to share space, repulsion between groups

Question 17

What types of strain are there in ring strain?

Answer 17

Steric strain
Angle strain
Torsional strain

Question 18

In rings of 3-4 carbons what type of ring strain is happening?

Answer 18

Angle and torsional

Question 19

in rings of 7-13 what type of ring strain is happening?

Answer 19

steric and torsional

Question 20

What’s more stable boat or chair?

Answer 20

Chair (groups further apart(staggered))

Question 21

What has higher energy boat or chair?

Answer 21

Boat, its more unstable

Question 22

What is more common in nature chair or boat conformation?

Answer 22

Chair since its lower in energy there isn’t a big energy barrier like there is to make boat

Question 23

What is the position called in a ring when the group is pointing up or down?

Answer 23

Axial (higher in energy)

Question 24

What is the position called in a ring when the group pointing outwards?

Answer 24

Equatorial (lower in energy)

Question 25

What has higher energy axial or equatorial?

Answer 25

Axial (groups closer together)

Question 26

Can rings flip?

Answer 26

Yes so axial and equatorial groups are swapped

Question 27

How to work out equilibrium constant for axial and equatorial positions?

Answer 27

Conc of equatorial/ conc of axial