May 22, 2012

Alicyclics and Aromatics

Rings of carbon are formed when a group of hydrocarbon come together to form a enclosed shape for example a hexagon. Their general formulais CnH2n, and when naming them, just add the prefix "CYCLO" infront of the main branch's name. for example, if a propane carbon chain has formed a triangle, it would be named as cyclopropane.
Cyclopropane
The cyclic hydrocarbons are more reactive, less stable and can also be branched. Cyclic hydrocarbons need at least three carbon atoms for it to form a ring.
When naming the compound, you can start from carbon atom and go clockwise or counter-clockwise. If there is only one side group, you do not need to put a number because we assume it starts at the very first carbon. When there is more than one side group, count clockwise or counter-clockwise from the first side group so that the lowest numbers are used.
cyclohexanone
Cyclic substituents are named the same way as they are in simple chains.
If there is a tie, we always sort them by alphabetical order.
Alkenes and Alkynes do not need numbers unless there is more than one double/triple bond because we always assume the bond starts from the first carbon.

Aromatics:
They usually have pleasant odours and contains at least one benzene ring (C6H6) which is a cyclohydrocarbon with 3 double bonds between carbon atoms.
The double bonds are delocalized so they can go anywhere and they are less reactive than cycloalkenes and cycloalpynes because of this.
Benzene
When naming aromatics, we name all the side groups first and then end with benzene.
If the benzene is a side group, we call it phenyl.


This video will sum up what we learned and is a great study guide for the test~! Enjoy
    

May 16, 2012

Functional Groups con'd


Carboxylic Acids
contain a double bonded oxygen with a carbon, and a single bonded base











To name this molecule, you drop the -e of a prefix and add -oic acid
eg ) ethanoic acid


Esters
Similar to carboxylic acids, but in stead you replace the base with an oxygen















Name from where this molecule is closer to the end of a chain. Then add -thyl and ends with -oate.
eg) methyl pentanoate



Ethers
contain an oxygen joining two hydrocarbon groups. Same as naming standard naming rules, change the ending to -oxy.
eg)  1-methoxyethane

CH3-CH2-O-CH3

Look at how the oxygen is attached to the CH3 closer to the right. So it is methoxy. The left over side group is ethane. The name of the whole chain is called 1-ethoxyethane.





Lastly, we covered amines in class. Here's a brief introduction of how to name amines.

May 15, 2012

Functional Groups

Functional Groups- organic compounds that contain elemtns other than C and H
  • most reactive part of the molecule
  • may be single atom (F, Cl, Br) or groups of atoms (NO2, NH2)

Halide and Nitro Compounds
*use di-, tri-, tetra- in front for multiple groups
Halogens
F = fluoro
Cl = chloro
Br = bromo
I = iodo
Nitro
NO2 = nitro
Ex/ 1, 1, 2, 2-tetrabromo ethane


Properties of Halogenated Compound
1. Insoluble in water
2. Unreactive
3. Compounds containing Cl or Br are more reative
4. Compounds containing I are very reactive

Properties of Nitro Compounds
1. Normally insoluble in water
2. Unreactive
3. Explosive
4. Have a pleasant odour

Alcohols
- an organic compound that contains OH functional group
- named by
  • using the longest carbon chain containing the OH group
  • replacing "e" ending with "ol"
  • multiple OH: diol, triol
*alcohol chains has to have the lowest number possible

Ex/ 1, 2, 3-butanetriol


Properties of Alcohols
1. Soluble. As you get longer chains, it becomes more insoluble.
2. Poisonous

Aldehydes and Ketones
- organic compounds containing carbonyl funtional group (double bonded oxygen)

Aldehydes
- has a double bonded oxygen at the end
- -al ending

Ex/ hexanal


Ketones
- double bonded oxygen not on either end
- -one ending

Ex/ 3-pentanone


Properties of Aldehydes and Ketones
1. Both partially soluble
2. Aldehydes are very active, and are easily converted or "oxidized" to Carboxylic Acids
3. Ketones are relatively unreactive

May 8, 2012

Organic Chemistry



These are examples of an organic compound.

Organic compounds are the compounds containing carbon in it.When the organic compound is burned, it produces carbon dioxide. It has low melting points, and it is weak or non- electrolytes.

Organic compound forms chains of carbon atoms in three different patterns:

Straight

Circular

Branched


*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--


Today, we are going to look close at Hydrocarbons

☆Alkanes (straight chain)

Alkanes is the hydrocarbon ( containing H & C). Alkanes are satuated, meaning that all carbon atoms are bonded by single bonds so no other atoms can bond to it. There are variety of types and different ways to represent them.

Their name end in '-ane' (ex, methane, octane)
To name Alkanes, put prefixes infront of '-ane' according to the number of carbons.
 

Series of organic compounds with a similar general formula and properties ( just like the one above) are called the homologous series.

☆Alkyl Group

Alkyl group is the alkane that has lost one hydrogen. This group occurs in the branched hydrocarbons.



Naming Hydrocarbons

Here is the steps you should take when naming the hydro carbons with only one bond.

1. Find and name the longest continuous carbon chain and place at the end of the name.
   (ex. diagram below; carbons in the blue rectangle → butane)
2. Identify and name groups (ex. diagram below; red circle → methyl) attached to the chain.
3. Number the chain from nearest side (from the group) to the other.
4. Represent the location of each side group by an approperiate numbers and names.
5. Assemble the name, listing groups in alpha betical order.

Ex. 2,3-dimethylbutane



*more than one of the same kind of alkyl grops are represented using prefixes (ex. di, tri,)





☆Alkenes


Alkenes are just like the Alkanes, but with one or more double bonds.
Alkenes are unsaturated hydrocarbons and are generally very reactive.
Alkenes end with "-ene"

Example: These are all homologous alkenes. As you can see, they all have double bonds.


☆Alkynes

Similarly, Alkynes are the hydrocarbon with one or more triple bonds.
Alkynes are unsatuated and they end with "-yne"

Example:



You would take same steps to name Alkenes and Alkynes as Alkanes EXCEPT that you are numbering the chain from the side closer to the double or triple bond. For example, on the example above, there is a triple bond located closer to the left end of the chain. So, you would have to number chain from left to right.... the name would be 5-methal-2-pentyne


If the geometry happen to have more than one bond, state the position of the bonds and add prefixes in front of "-ene" or "-yne" (ex. 3,7-decadiene)


Since same formula can have different geometry, (= Gemetric isomers) "Cis" and "Trans" are put in front of the name of hydrocarbons to identify the geometry.

 This kind of geometry, with larger group () above is named with "Cis"
This kind of geometry, with larger group () located vertically is named with "Trans"
No need to write "Cis" nor "Trans" for this kind :)




This video will help you understand more about hydrocarbons.