No Added Chemicals

A. Structure The structure of benzene was suggested firstly by Kekulé as a cyclic molecule but he also thought benzene had alternative single and double carbon-carbon bonds. The Kekulé structure is expected that benzene undergoes addition reaction. However, benzene is far less easily to undergo addition reaction than alkene, such as cyclohexene. Besides that, the carbon-carbon bond lengths of benzene are all identical, with the lengths intermediate between those single and double bonds.

A. Carbonyl Compounds (Aldehydes and Ketones) The main feature of carbonyl compounds is there is at least one atom carbon has double bond with oxygen atom. There are two types of carbonyl compounds which are aldehyde and ketone. The structure of aldehyde and ketone are shown below.

In this section, we will try to see the reaction in organic chemistry and also the mechanisms. You will notice in later part there will be a lot of arrows in the mechanisms. Those arrows have meanings, so please pay attention about the arrows below. The direction of the arrows is important. The direction of the arrow represents the movement of electrons. Therefore, remember to flow the arrow from highly density of electrons to the lower one. The shape of the arrow is important as well. Full arrow represents a pair of electron and half arrow represents an electron

A. Hydrocarbon 1. Alkanes Alkane is basically the single-bonded between carbon atoms, so alkane is called saturated hydrocarbon. It is called saturated hydrocarbon because there are no more atoms could be added to the bonding between carbon-carbon atoms. The general formula of alkanes is C n H (2n+2) and if it has branches, the properties would be different even they share the same molecular formula. Could you give the reasons why this property could happen? (Hint: the definition of boiling point)