3. Stereochemistry

Question 1

what are isomers in terms of type and number of atoms

Answer 1

same type of atoms

same number of atoms

Question 2

what are the 2 types of isomers

Answer 2

stereoisomers

constitutional isomers

Question 3

what are constitutional isomers in terms of molecular formula and connectivity of atoms

Answer 3

same molecular formula

different connectivity of atoms

Question 4

what are stereoisomers in terms of molecular formula and connectivity of atoms

Answer 4

same molecular formula

different spatial orientation of atoms

Question 5

how does geometric isomerism occur for alkenes and cyclic compounds

Answer 5

cis and trans compounds

Question 6

what are cis isomers

Answer 6

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

Question 7

what is a trans isomer

Answer 7

when substituents are on opposite sides of the ring or double bond

Question 8

is the cis or trans isomer more stable and why

Answer 8

trans more stable

substituents are further apart and there are less steric repulsions

Question 9

what are chiral objects

Answer 9

objects that are not superimposable on their mirror images

Question 10

what are chiral centres

Answer 10

carbon that is connected to 4 different groups

Question 11

how many ways are there to arrange 4 groups around a chiral centre

Answer 11

only 2

Question 12

how do the 2 chiral arrangements differ from each other

Answer 12

differ in spatial arrangement

Question 13

what is an enantiomer

Answer 13

when a compound that is chiral, it will have one non superimposable mirror image

Question 14

what is R/S configuration assigned to

Answer 14

assigned for each chiral centre

Question 15

what are the 3 steps to determining R/S configuration for chiral centres

Answer 15

1. assign priorities to each of the 4 groups connected to chiral center according to atomic # (highest atomic # = highest priority)
2. rotate molecule so 4th priority atom is on the dash (facing backwards)
3. count other 3 atoms and determine if its clockwise or anticlockwise

Question 16

if the atoms around a chiral carbon are ordered in priority and go clockwise is it R or S configuration

Answer 16

R

Question 17

if the atoms around a chiral carbon are ordered in priority and go anticlockwise is it R or S configuration

Answer 17

S

Question 18

do enantiomers have similar physical properties to each other

Answer 18

yes

Question 19

do diastereomers have similar physical properties to each other and why

Answer 19

no as they arent mirror images of each other

Question 20

what is the equation for finding the maximum number of stereoisomers

Answer 20

max # of stereoisomers = 2^n

n = # of chiral centres

Question 21

any compound with 1 chiral center must be ___ compound

Answer 21

chiral compound

Question 22

any compound with 2 chiral center must be ___ compound

Answer 22

chiral or achiral

Question 23

any compound has a plane of symmetry it must be ___ compound

Answer 23

achiral

Question 24

any compound lacks a plane of symmetry it must be ___ compound

Answer 24

most likely chiral - chiral for GAMSAT

Question 25

what are meso compounds

Answer 25

achiral compound if it has chiral centres and a plane of summetry

Question 26

if a group of stereoisomers contains a meso compound what happens to the maximum number of stereoisomers

Answer 26

there will be less than 2^n stereisomers

Question 27

for fischer projections what do the horizontal lines mean

Answer 27

they are coming out of the pages towards you

Question 28

for fischer projections what do the vertical lines mean

Answer 28

they are going into the page away from you