ochem

Question 1

structural isomerism

Answer 1

Compounds having the same molecular formula but different structures

Question 2

conformational isomerism

Answer 2

a form of stereoisomerism in which the isomers can be interconverted just by rotations about formally single bonds.

There are three types of conformational isomers: rotamers, staggered conformers, and eclipsed conformers

Question 3

paraffins

Answer 3

indicating hydrocarbons with the general formula CnH2n+2.

Question 4

cycloparaffins

Answer 4

any of a series of saturated alicyclic hydrocarbons of the general formula Cn H2n, having a closed chain of three or more carbon atoms, Ex cyclohexane

Question 5

cis-trans isomerism

Answer 5

pairs of molecules which have the same formula but whose functional groups are in different orientations in three-dimensional space

Question 6

dienes based on the positions of the double bonds

Answer 6

Cumulated Diene: A cumulated diene has two successive double bonds on adjacent Carbon. They are also called Allene

Conjugated Diene: A conjugated diene has two conjugated double bonds separated by a single bond.

Isolated Diene: An isolated diene has two double bonds separated by two or more double bonds.

Question 7

Aromatic compounds

Answer 7

chemical compounds that consist of conjugated planar ring systems accompanied by delocalized pi-electron clouds in place of individual alternating double and single bonds.

ex: toluene and benzene

Question 8

Huckel’s rule

Answer 8

The Huckel 4n + 2 Pi Electron Rule

when the total number of pi electrons belonging to the molecule can be equated to the formula ‘4n + 2’ where n can be any integer with a positive value (including zero).

Question 9

The carcinogenic effect
of aromatic hydrocarbons

Answer 9

Aromatic hydrocarbons, particularly polycyclic aromatic hydrocarbons (PAHs), have been associated with carcinogenic effects

DNA Damage leading to cancer

Question 10

Molecular mechanism of vision

Answer 10

light enters the eye and hits a molecule called 11-cis-retinal that is located within a protein called rhodopsin

The absorption of light causes the 11-cis-retinal to undergo a structural change, or isomerization, converting it into all-trans-retinal

Question 11

chiral molecules

Answer 11

a molecule that is nonsuperimposable on its mirror image

Question 12

achiral molecules

Answer 12

A molecule or ion is achiral if it is superimposable, i.e. it can be superimposed on its mirror image

Question 13

Optical activity

Answer 13

the ability of a chiral molecule to rotate the plane of plane-polairsed light

Question 14

Constitutional isomers

Answer 14

molecules with the same molecular formula but different connectivity of atoms.

Question 15

configuration

Answer 15

refers to the spatial arrangement of atoms that can only be changed by breaking bonds.

Question 16

Enantiomers

Answer 16

are pairs of compounds with exactly the same connectivity but opposite three-dimensional shapes. Enantiomers are not the same as each other; one enantiomer cannot be superimposed on the other. Enantiomers are mirror images of each other.

Question 17

diastereomers

Answer 17

two molecules which are stereoisomers (same molecular formula, same connectivity, different arrangement of atoms in space) but are not enantiomers. are not mirror images of each other and non-superimposable.

Question 18

racemates

Answer 18

a racemic mixture or racemate one that has equal amounts of left- and right-handed enantiomers of a chiral molecule or salt.

Question 19

meso compound

Answer 19

an achiral compound that has chiral centers. A meso compound contains an internal plane of symmetry which makes it superimposable on its mirror image and is optically inactive although it contains two or more stereocenters

Question 20

Resolution

Answer 20

is the separation of a racemic mixture into its respective enantiomers. Since enantiomers are identical, they must first be converted into diastereomers, which have different energies and are easy to separate.