STEREOCHEMISTRY

Question 1

what are isomers

Answer 1

same type and number of atom

Question 2

what are the two types of isomers

Answer 2

constitutional isomers
stereoisomers

Question 3

what are the further types of steroisomers

Answer 3

Enantiomers
Cis/Trans isomers
Diastereomers (conformers/rotamers)

Question 4

what are constitutional isomers

Answer 4

same molecular formula

different connectivity of atoms

Question 5

what are stereoisomers

Answer 5

same molecular formula

different spatial orientation of atoms

Question 6

how does geometric isomerism occur

Answer 6

occurs through cis and trans compounds

Question 7

what does geometric isomerism occur in

Answer 7

In alkenes and cyclic compounds

Question 8

how does a compound become a trans compound

Answer 8

substituents on opposite sides

Question 9

how does a compound become a cis compound

Answer 9

substituents are on the same side of the ring or double bond

Question 10

what composition of compound is more stable, trans or cis

Answer 10

trans

Question 11

why is a trans isomer more stable than a cis isomer

Answer 11

substituents are further apart and there is less steric repulsion

Question 12

what interaction would occur within cis-2-butene that makes it less stable

Answer 12

steric interaction [as substituents closer together]

Question 13

what are chiral objects

Answer 13

not superimposable on their mirror images

Question 14

what does achiral mean

Answer 14

superimposable on their mirror images

Question 15

what does a chiral molecule contain

Answer 15

a carbon atom that is connected to four different groups.

This carbon that is connected to four different groups is called the chiral centre.

Question 16

what makes two compounds stereoisomers

Answer 16

when the two compounds only differ from each other in spatial arrangement

Question 17

what is an enantiomer

Answer 17

When a compound is chiral, it will have one non-superimposable mirror image. This is called an enantiomer.

Question 18

what do enantiomers properties have in common

Answer 18

similar physical properties to each other

Question 19

what are the steps to using the cahn-ingold-prelog system

Answer 19

1) assign the group in atomic number where highest atomic number given highest priority
2) make sure the lowest/fourth priority group is on the dash
3) count from 1-3 with an arrow to determine

Question 20

when assigning priority number by highest atomic number - WHAT HAPPENS if the atom of the group the carbon is attached to is the same

Answer 20

if they are the same element i.e. carbon, then choose which group is more significant. so en ethyl group would take priority over a methyl group

Question 21

how do you adjust so that the 4th group is on the lowest priority wedge

Answer 21

swap adjacent 4th priority group to the wedge
then swap other two numbers with each other

Question 22

what happens if from 1-3 is anticlockwise

Answer 22

s-enantiomer

Question 23

what happens if from 1-3 is clockwise

Answer 23

r-enantiomer

Question 24

how is a double bond considered in cahn-ingold-prelog when assigning the priority number

Answer 24

2 separate bonds

Question 25

how is a triple bond considered in cahn-ingold-prelog when assigning the priority number

Answer 25

3 separate bonds

Question 26

according to cahn-ingold-prelog, how many bonds would carbon be bonded to from carbon dioxide on one oxygen

Answer 26

2 oxygen (due to double bond on the oxygen)

Question 27

breakdown what (2R,3S)-3- methyl-2-pentanol means

Answer 27

there are two chiral centres
one at 2 - which is right configuration enantiomer
one at 3 - which is left configuration enantiomer

Question 28

what are Diastereomers

Answer 28

stereoisomers that are not mirror images of one another.

Question 29

what is an example of Diastereomers

Answer 29

Cis/trans isomers