Organic Chemistry - 3)c) Stereochemistry

Question 1

what are the two different types of stereoisomerism?

Answer 1

geometric isomerism
optical isomerism

Question 2

why do trans isomers have higher melting points?

Answer 2

they are a straighter molecule and have more effective packing and therefore have stronger intermolecular forces and require more energy to melt

Question 3

why do cis isomers have a higher boiling point than trans isomers?

Answer 3

they have stronger intermolecular forces

Question 4

what is optical isomerism?

Answer 4

occurs in molecules that have a central carbon atom with four different atoms or groups attached tetrahedrally.

Question 5

what term is used to define the mirror-image molecules which are optical isomers?

Answer 5

enantiomers

Question 6

what is meant by the chiral centre or chiral carbon?

Answer 6

the carbon atom which has four different atoms or groups attached

Question 7

in infrared spectroscopy, what can be said about the bonds in relation to the vibrations?

Answer 7

the stronger the bond, the higher the frequency of the vibrations

Question 8

where on the electromagnetic spectrum does the vibrational frequency of atoms lie?

Answer 8

infrared region