chem 31.1 manuals
Exercise 5
INTRODUCTION TO STEREOCHEMISTRY
I.
Introduction
Stereochemistry is concerned with the shapes of molecules and how the differences in shapes can effect the properties and reactions of compounds.
Subtle differences in molecular shape have far – reaching consequences and it is probably the field of molecular biology that a full awareness of molecular shapes has emerged. A knowledge of the molecular shapes of such vital compounds as sugars, amino acids, and proteins is essential in understanding their reactions and properties.
Molecular structures are so frequently represented in two dimensions that we often experience considerable difficulty in thinking about molecules in three dimensions. The purpose of this exercise is to persuade you to think in three dimensions. II.
Chirality, Enantiomerism, Diastereomerism and Optical Activity.
Objects which are IDENTICAL are SUPERIMPOSABLE – that is, when we imagine the two objects are “used” together, all the corresponding parts match exactly. Thus, a sphere is superimposable on another sphere of the same diameter. A sphere, however, is not superimposable on a cube nor on a sphere of a different diamter.
1. Determine whether each of the following pairs of objects are identical with each other, i.e. superimposable
a) two forks
b) your left hand and your right hand
2. View your right hand in front of the mirror
a) Is the reflection of your right hand superimposable on your left hand?
b) Is your right hand the mirror image of your left hand?
3. Using a mirror, decide whether the following objects are superimposable on their mirror images.
a) a fork
b) a pentagon
c. your left hand
4. A PLANE OF SYMMETRY is an imaginary plane or sheet that divides the objects so that one half is exactly a reflection of the other half. Determine whether each of the following has at least one plane of symmetry.
a) a sphere
b) a regular tetrahedron
c) a shoe
5. Determine whether
INTRODUCTION TO STEREOCHEMISTRY
I.
Introduction
Stereochemistry is concerned with the shapes of molecules and how the differences in shapes can effect the properties and reactions of compounds.
Subtle differences in molecular shape have far – reaching consequences and it is probably the field of molecular biology that a full awareness of molecular shapes has emerged. A knowledge of the molecular shapes of such vital compounds as sugars, amino acids, and proteins is essential in understanding their reactions and properties.
Molecular structures are so frequently represented in two dimensions that we often experience considerable difficulty in thinking about molecules in three dimensions. The purpose of this exercise is to persuade you to think in three dimensions. II.
Chirality, Enantiomerism, Diastereomerism and Optical Activity.
Objects which are IDENTICAL are SUPERIMPOSABLE – that is, when we imagine the two objects are “used” together, all the corresponding parts match exactly. Thus, a sphere is superimposable on another sphere of the same diameter. A sphere, however, is not superimposable on a cube nor on a sphere of a different diamter.
1. Determine whether each of the following pairs of objects are identical with each other, i.e. superimposable
a) two forks
b) your left hand and your right hand
2. View your right hand in front of the mirror
a) Is the reflection of your right hand superimposable on your left hand?
b) Is your right hand the mirror image of your left hand?
3. Using a mirror, decide whether the following objects are superimposable on their mirror images.
a) a fork
b) a pentagon
c. your left hand
4. A PLANE OF SYMMETRY is an imaginary plane or sheet that divides the objects so that one half is exactly a reflection of the other half. Determine whether each of the following has at least one plane of symmetry.
a) a sphere
b) a regular tetrahedron
c) a shoe
5. Determine whether