Answer to Question 1
A carbon-carbon double bond assumes that each carbon is bonded to three atoms
Answer to Question 2
In the condensation reaction every monomer molecule can react with equal probability upon encountering any monomer of the opposite type. This situation favors the formation of many small chains which grow simultaneously. As the chains get larger, their ability to continue reacting is slightly less than small chains because the large chains have less mobility and, therefore, less chance to encounter a monomer with which it can react. Also, in condensation polymerization the byproduct of water is formed as the monomers react. The presence of water molecules in the reaction will hinder chain formation by diluting the reactants. In addition polymerization, encounters between monomers do not form bonds unless one of the monomers has been initiated, that is, reacted with an initiator so that the monomer contains a free radical. Therefore, in addition polymerization, since only a few of the monomers are initiated, the growth of the chains will be largely at the sites that are on the already formed polymers, thus making those polymer chains even longer.
Structure of the DNA double helix
Emphysema. (a) Illustration comparing normal lungs and emphysemic lungs. The inserts illustrate how
Hydrogen bond
Amino Acid carbon skeleton
Metallic bond
Functional Groups of Carbon