Stereochemistry and aromaticity questions.

1. Give concise definition for each of the following terms:

1. Stereochemistry
2. Angle strain
3. Torsional strain
4. Enantiomers

2. When a molecule of propane and cyclopropane are burnt separate in air give different amount of energy. Which one would produce higher amount of energy than the other? Explain your answer.
3. A sample of pure R-enantiomer has a specific rotation of -40°. A mixture of R-/S enantiomers has an observed optical rotation of +22. Calculate

1. Optical purity
2. COmposition of the mixture

1. What do you understand by chirality of organic molecule?
2. With at least one example in each case briefly explain the three origin of chirality
3. Identify stereogenic centers in each of the following molecules; use a symbol of star to indicate the stereo genic centers.

4-methyl-2-hexanol can be represented into four stereoisomers.

1. Draw the four stereoisomers of the compound
2. Assign the R/S designation of each of the stereogenic center
3. Give the relationship between the drawn stereoisomers

Aromatic compounds are defined as having planar structures, containing a certain number of electrons in a continuous overlapping cyclic arrangement of p orbitals. Name two characteristic physical or chemical properties of aromatic compounds.

Give concise definition for each of the following terms:

1. Stereochemistry
2. Optical isomers
3. Enantiomers
4. Meso compound

Using a simple chart show the classification of isomers.

Draw the fisher structures for 2,3-dihydroxybutane based on the following:

1. being meso compound
2. diastereoisomers

Write the structure of an isomer of which is optically active and assign its configuration.

Draw Newman projections for;

1. Cyclopentane
2. 1-Chloro,4-methylcyclohexane
3. Cyclobutane

Deduce all possible stereoisomers of the molecule with following formula