Alicyclics & Aromatics

Cyclic hydrocarbons, or alicyclics are ring-shaped structures that can act as either a parent chain of a side group.

• general formula = CNH2N
• more reactive as opposed to straight-chains
• numbering can start anywhere on the ring, but the #'s of the side chains must be the lowest possible numbers
• prefix "cyclo-" is added to the beginning of the parent chain

Naming

Cycloalkanes

1. count length of carbon chain
2. similar naming rules as straight-chains
3. if the numbers of the side groups are equal (ex. 2,4,6 either way you count) then you give the lower number to the side group that comes first in the alphabet

Cycloalkenes & Cycloalkynes

1. similar naming to cycloalkanes, except with different endings
2. more reactive than cycloalkanes
3. when numbering the double/triple bonds, they should always be located at the first and second carbons

Aromatics

Properties

• electrons are "delocalized" meaning they can move around the ring and are shared equally in the ring
• carbon-carbon bonds have same reactivity because of delocalization
• less reactive structures than cycloalkanes
• have a nice odour
• contains atleast one benzene ring

Naming

• can be a parent or side chain
• as a side chain, its given the name "phenyl"
• as a parent chain, "benzene" is added to the end of the whole name

Ex. Name the structures:
                                                 
                                                              cyclopentyne


                                       
                                                       4-chlorocyclohexene


All this organic chemistry is tough! It's a lot to memorize and there are a lot of rules to follow. But rest assured, it gets easier. Try these exercises. After all, practice makes perfect right? :)







                              

                                                     

Halides & Nitro Compounds

Hydrocarbons (molecules composed of hydrogen and carbon atoms) are the foundation of organic chemistry. They are the base of a organic structure, and we can add side groups to the base! Kind of like a tree! The hydrocarbon chain of the molecule is the roots and the trunk of a tree, and the side groups are the branches! Let's look at some possible "branches":

Halides

Properties

1. Insoluble in water
2. Compounds that contain Iodine are really reactive
3. Compounds that contain Chlorine or Bromine are reactive under certain conditions

List of Halogens

Br = Bromo
Cl = Chloro
F = Fluoro
I = Iodo

**When the molecule contains more than one halogen, we use the suffixes (di-, tri-, tetra-, penta-) to represent it. The suffix goes before the halogen (ex. tetrabromo; diiodo)


Nitros

Properties

1. Usually insoluble in water
2. mostly nreactive unless put under certain conditions
3. have a generally nice odour
4. Likely to be explosive (ex. trinitrotoluene, or TNT)

Nitro
NO2 = Nitro


Naming

Naming of these structures is similar to that of hydrocarbons. You simple count the smallest # of carbon atoms until you reach the halide or nitro and the # goes before the name.

• side groups go before the parent chain
• side groups go in alphabetical order

Ex. Name the structure
                                                  
                                                             2-bromopentane

1. Count the longest chain of carbon atoms, in this case 5, or pentane *each point you see in the picture represents a carbon atom*
2. Count the smallest # of carbon atoms until you hit bromine, in this case, it's 2!

                        

Amines

Amines serve many purposes and like all functional groups, are used a lot in our society.  They are used in medicine, the textile industry, as flotation agents and stabilizers, to name a few. 

Amines have fairly high boiling points and produce fishy smells. 

Amines are based on the structure of Ammonia.  NH3.  Nitrogen has 5 electrons, are so it will bond with 3 other electrons to try and become stable.  There are three types of amines.  Primary, secondary, and tertiary.  In primary bonds, a Nitrogen bonds with 1 Carbon and 2 Hydrongens.  In secondary, Nitrogen bonds with 2 Carbons and 1 Hydrogen. And you guessed it, in tertiary, Nitrogen bonds with 3 Carbons.

General Structure:

The 'H's don't necessarily have to be Hydrogens.  They can also be Carbon chains. Amines, like ethers, are side groups.

Naming Rules

1) Identify the longest Carbon chain and name it. 

2) Where the Nitrogen branches off is the start of the side group.  Count the number of Carbons attatched to this.  Name it with amino(primary amine) before the parent chain. 

3) If the Amine group is not located on the first Carbon, identify the location.

Let's do an example. 

The longest chain is pentane, so that is the ending of your name.  The lowest number your amine group can be on is 2.  Thus 2-aminopentane.

Note: nitro group are NO2.  Amines are NH2. 

And here's a wonderful song to help you study for a test or distinguish the different functional groups.

It's a Chemistry Thing Song

Here's a good site if you need more help.

Review

Khan Academy also has many great videos.

Alkenes & Alkynes

Alkenes and Alkynes

Alkenes and alkynes are similar words...2 words off by a factor of one letter. Now they may seem similar, but are they in fact similar? Yes they are! Similarly to their names, their bonds are off by a factor of one; alkenes are double bonds, and alkynes are triple bonds. And they are also really similar to alkanes. Think of them as the three stooges.. or the three amigos! Whatever you choose to relate them to, just remember, alkanes -1 bond, alkenes – double bond, alkynes – triple bond.

Naming
   
    Alkenes

• General formula = CNH2N
• Naming is similar to alkanes
• Double bond placement is at lowest possible # and placed in front of parent name
• Find longest chain of carbon atoms and change the ending from the prefix –ane to –ene (ex. butane is changed to butene)
• Count the # of carbon atoms until you reach the double bond. Count from both sides of the chain to see which has the smallest #
• Write #’s of side groups and their names. **Side groups should be in alphabetical order!!**

Ex. Name this structure

             

                                        

                                                                         2-pentene

1. Count the longest chain of carbon atoms. In this case, it's 5, which is where we get the pentene.  
2. Count to see on which carbon atom the double bond is placed. So it's either on the 3rd or 2nd carbon atom, but we want the smallest #, so we'll go with the 2nd.

Sometimes, with double bonds you will get structures that are the same but have different geometry. These structures are called geometric isomers:

                               
                                          trans-2-butene                      cis-2-butene
   
In the example above, we have 2-butene. As you can see, they have the same structure, just the placement of the atoms is different.To distinguish the 2, we use "cis" and "trans".

• "cis" is used when the carbon atoms are above/below the double bonded centre of the structure
• "trans" is used when the carbon atoms go in a diagonal

When naming, add the "cis" or "trans" (which ever applies to the situation) to  the beginning of the name.


   Alkynes

• General formula = CNH2N - 2
• Ending changed from prefix -ane to -yne (ex. nonane is changed to nonyne)
• Double/triple bond placement is at lowest possible # and placed in front of parent name
• Count the # of carbon atoms until you reach the double bond. Count from both sides of the chain to see which has the smallest #
• Write #’s of side groups and their names. **Side groups should be in alphabetical order!!**

Ex. name the structure

                                   
                                                              heptyne

1. Count the longest chain of carbon atoms. In this case, 7, which gives us heptyne.
2. The smallest # of the placement of the triple bond is 1, but we don't need to write the 1 out, it is assumed it's 1 if there's no # before it

And that's it for alkenes and alkynes! Hopefully you understood and it wasn't too hard. Organic chemistry is confusing, but it just takes time and practice to get used to it.



 Extra help!

http://www.youtube.com/watch?v=6NygjuEFkIc

http://www.youtube.com/watch?v=oYoQpDtBLac

Ethers

Ethers are commonly used in manufacturing. 


Ethers have a definite bond angles of 104.5 degrees and have low boiling points. 

There general structure is:


Each 'R' represents a Carbon chain.  They are not necessarily the same.  They are connected by an Oxygen atom which is single bonded to both of them.

Rules for naming:
1) Identify the longest Carbon chain attatched to the Oxygen.  Name it.
2) Take the other chain and treat it like an alkyl group.  However, first take off the'yl' and add 'oxy'

Fairly simple and straightforward for once!!! So let's do a harder example right away!

Find the longest chain, butane.  Then there is the ether, which is not located on the first Carbon.  However, the side group is still methyl.  So the molecule is 2-methoxybutane!

Esters

Esters are mostly used in plastics and as food flavourings.  Do you like orange, or apple, or pear? Here are some structures and the wonderful flavours they produce.

Because they have no free 'OH' groups, they have a tendancy to be insoluable in water.  They are known as acid derivatives.  Often they have a pleasant and fruity odour.

So what do they look like?

Like always, the 'R' represents a Carbon chain.  R' means that there is another Carbon chain but is not necessarily the same as the other.  All esters have a double bonded oxygen as well as another oxygen(single bonded).

Esters are side groups(substituents), so when you name them, the single bonded oxygen is the start of your side chain. The double bonded Oxygen already has a full shell so it is unlikely to react/have other bonds.  

Rules for naming:

1) Name the main chain.  Take off the 'e' and add 'oate' to the end.

2) The side group starts after the oxygen.  Count the number of Carbons in the chain attatched to it.

3) Name this group as an alkyl.

Let's practise:

First we identify the main chain, which is propane.  Then we take off the 'e' and add the suffix 'oate'. Thus: propanoate.  Now we need to name the side chain.  It's methyl, so its final name is methylpropanoate.

Here's a cool little video about a queen and king to help you remember esters:

Esters Fairytale

Carboxylic Acids

Where would our world be without painkillers like aspirin?

Organic acids are very important in todays society.  Some other uses of carboxylic acids include: in medicine, and food, as preservatives, and the manufacturing of soap, rayon, rubber, and various perfumes. 

They are polar compounds and generally have high boiling points.  Although they have they word 'acid' in their name, many are just weak acids.  The majority produce strong odours. 

The general formula of a carboxylic acid is:



'R' represents a Carbon chain.  In a organic acid, there is always a double bonded Oxygen with a OH group.  Does this remind you of something??? It should.  Carboxylic acids = Alcohol + Aldehyde!

Rules that you must follow-from the IUPAC (it's not me setting these rules)

1) Identify the longest carbon chain containing the carbonyl group and OH at the end.

2) Assign each Carbon a number.  Give #1 to the Carbon bonded to these groups.

3) Count the number of Carbons.  This will be your parent chain so name the chain as if it were an alkane.

4) Take the 'ane' off the end and add the suffix 'oic acid'.

5) Name the other branches and add them to the name at the beginning.  Arrange them in alphabetical order.  

Shall we do some practise?

So we know that this is a carboxylic acid because of the elements in red.  Now we have to count the number of Carbons: 5.  So the alkane version would be pentane, but because it's an organic acid,  we replace the 'ane' with 'oic acid'.  Thus, it becomes pentanoic acid.  We don't need to say 1-pentanoic acid because the 1 is implied. 



Need more help, watch this video:

Khan- carboxylic acids

How are differnet flavours made? They are made by different combinations of alcohols and carboxylic acids!





Ketones

Are you tired of all the functional groups? Try this song, by the band the Keytones.  It might just brighten your day and making studying a little more pleasant!  Their name's not quite the same, but I accidently stumbled on it because I have horrible spelling.

The Keytones- It's Good to be Alive

Keytones have a variety of uses.  They can be uses as welding agents, industrial solvents, and is a type of sugar.

Erythlurose: ketone sugar found in rasberries.

Ketone bodies are three molecules used in our bodies.  They are used as an energy source for our hearts and brain.  As you can see, they are very important!

Keytones are often acidic.As well, often they  form cyclic patterns.

 

There general structure is:

Each 'R' stands for a Carbon chain.  R' means that the Carbon chain may or may not be different from the one on the left.  As you can see, there is once again another Carbonyl group.  The Oxygen is double bonded to the Carbon(the intersection).

What's the difference between Aldehydes and keytones? Aldehydes are only bonded to one Carbon chain whereas ketones are bonded to two.  Remember: R and R'.  An easy way to remember is:

aldeHYDes have HYDrogens and Ketones have Karbon chains.

It's like Ariel and her sisters all over again, but this time it's a different sister. 

Rules for naming ketones.

1) Identify the longest carbon chain.

2) Assign each Carbon a number.  Give the lowest numbers possible.  Instead of 4,4,5 make it 1,2,2. 

3) Count the number of Carbons.  This will be your parent chain so name the chain as if it were an alkane.

4) Take the 'ane' off the end and add the suffix 'one'.

5) The ketone isn't necessarily at the beginning of the chain so you must dicate its location.

6)Name the other substituents and add them to the name at the beginning.  Arrange them in alphabetical order.  

 

Let's do some practise.

Count the number of Carbons.  There are 6, so the chain without the double bonded Oxygen would be hexane.  Then add the suffix 'one' by taking off 'ane'.  But note that the Carbonyl group isn't on the '1' Carbon so you need to give it the lowest possible number(2).  Write the number before the chain name.  Therefore 2-hexanone.

 

Now let's do a slightly trickier one.

Find the longest chain of Carbons with the Carbonyl group.  You see that the chain will be 4 Carbons long and that there will be an extra methyl group.  Add this after naming the main chain.  The double bonded Oxygen sits on the second Carbon so the parent chain is 2-butanone. The methyl group sits on the third Carbon so the name is 3-methyl.  Put the two together and, voila! 3-methyl-2-butanone!

 

 

Polarity and Electronegativity

Polar Molecules: asymmetrical and have at least one dipole present. An example would be an ionic bond.

Non-polar molecule: symmetrical and at least one dipolar bond. (value of the difference is less than 0.5) These would be covalent bonds. Thus, the electrons are shared equally.

here are more examples! 

Positive ions, also known as electropositive, have very low electronegativities. Here is an electronegativities table to help you out! As you go up the column, the electronegativity increases. 

Aldehydes

Although you might think of hides when you first hear the word 'aldehyde', You're way off. 

Aldehydes are a class of organic molecules.  They are very useful (not as furry rugs on the floor or coats).Two of the most important aldehydes are formaldehyde and acetaldehyde.  They are used in the sysnthesis of other chemicals, disinfectants and preservers.

Aldehydes mostly release pleasant odours.  They are essentially alcohols that have lost the Hydrogen atom. 

This is their general formula.

 

In this diagram, the 'R' represents a Carbon chain.  It can be very long or non-existant(methanal).  The Carbon atom double bonded to the Oxygen is called a carbonyl group.  Aldehydes always have a Hydrogen atom attatched to their structure (whereas ketones have Carbon chains on both sides)

Rules for naming Aldehydes:

1) Identify the parent chain (it must have the Carbonyl group at the end).

2) Count the number of Carbon atoms on the longest chain.

3) Assign each Carbon a number- the Carbonyl group counts as '1'.

4) Name the molecule as if the Carbonyl group wasn't there (ethane, propane, butane, etc)

5) Remove the 'e' from the end of the name and add the suffix 'al'.

Note: Similarly to naming alcohols, if there are multiple Carbonyl groups, add prefixes(di, tri, tetra, penta, etc.) before the 'AL' but after the alkane name. 

Can you see how similar aldehydes and alcohols are? They are like sisters; relatively similare in structure, but with very different personalities! Ariel's sisters are very dutiful and obey their father.  Meanwhile, Ariel is off going up to shore where she is forbidden!

Now for some practise.





First, figure out what type of molecule this is.  Since there is a Carbonyl group at the end, we can conclude that it is a aldehyde.  Next, count the number of Carbons on the longest chain.  Name the molecule as if there was no Carbonyl group.  So, butane.  Then add take off the ending 'e' (we can leave 'an' because there are no double bonded Carbons) and add 'AL'.  So the final name for our molecule is butanal!

Let's try another, this time we have to name the molecule.

4-ethyloctanal

First draw the parent chain:

Because the ending is octanal, take off the 'AL' and add 'ane'.  Thus, octene.  Draw the chain.

Next, make the molecule an aldehyde.  Add the double bonded Oxygen at the end of the structure.  Assign the number '1' to the Carbon and number the remaining Carbons.

Now all we have to do is add the substituent groups.  Remember that the Carbon double bonded to the Oxygen is 1!

And there you go.  4-ethylbutanal!

Well, there's probably no chance that the test will be cancelled; its' been sunny all week.  But, I wouldn't share his disappointment...

Hitler finds out his exam is cancelled