Alcohols

Butanol, that's an alcohol, right.  So it must be safe to drink?

WRONG.

Butanol is used as a fuel.  If you are a human(hopefully), you wouldn't want to injest any of that...



Although we use the term alcohol to refer to the beverages we drink, the only one we actually drink is ethanol.  There are many other alcohols like methanol, propanol, and glycerin.  Alcohols are often used in the pharmacutical industry, to isolate compounds and to obtain dynamite.  Many are poisonous, and can kill you.  For example, propanol(rubbing alcohol) is often used in hand sanitizers. 



While this may look innocent to you, used incorrectly, may cause you death.  Just propanol can cause central nervous system poisoning or a coma.  You die if your respiratory system no longer functions.   

Click the link below to hear a funny song about ethanol.
St. Patrick Day Song- Alcohol



So what makes an alcohol an alcohol?

Alcohols are all colourless, odourless liquids.  They have high boiling points because of the strong attraction between the hydrogen and the carbon atoms. The longer the Carbon chain, the less soluable the molecule is.

Alcohols all have the funtional group "OH" attatched to their structure.

This is the general model:

In this diagram, the 'R' represents a Carbon chain. 

Although they have 'OH' in their structure, they are NOT necessarily basic. 

Naming Rules:

1) Identify the longest carbon chain with the group 'OH'.

2) Assign each Carbon a number.  Give the lowest to that bonded to the 'OH'.

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 'ol'.

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

Let's do an example.    

If each intersection represents a Carbon atom, there are five.  Without the 'OH', this would be a pentane molecule.  Take off 'ane' from the ending and replace it with 'an'(because it's still an alkane) and add 'ol'.  Simple.  Thats it. The molecule is pentanol. 



Now for a harder one. 

HO-CH

The longest Carbon chain consists of two Carbons.  Therefore, without the 'OH's it would be called ethane. Since there is more than one group of 'OH', we need to identify this in the name.  We use the prefixes di, tri, tetra, penta, etc. to convey this information.  We put this in front of the suffix 'OL'.  So, ethandiol.  As well, the 'OH' groups are not both bonded to the first Carbon, so we need to dictate their locations. 
The final name of this molecule is 1,2-ethandiol.

2-CH2-OH

THE NAME'S BOND. CHEMICAL BOND.

When particles are charged, they are either going to attract or repel each other. As a result from this attraction/repulsion, there is a force. This is force is the... 

                                        
                                                  ELECTROSTATIC FORCE!

There are different relationships for different particles:

1. Like charges repel
2. Opposite charges attract
3. The greater the distance between particles, the less electrostatic force there is
4. The less distnace between particles, the more electrostatic force there is

**Electrostatic charge is applied in ALL DIRECTIONS. We tend to think that the attraction/repulsion only occurs in one direction, but in fact it's in every direction!

                       

                          

                      This image shows force that occurs in ALL DIRECTIONS!



Ionic Bonding

• ionic bonding occurs between the attraction of a postive ion to a negative ion
• electrons are transferred from one ion to another
• atoms will transfer electrons in order to try to gain a closed shell *electrons are transferred, not shared!!*
• transfer of electrons creates one positive or negative ion
• positive ions usually lose their valence electrons, negative ions usually gain these valence electrons
• the bond between the ions is so strong that requires a huge amount of energy to break the bonding

You see how in the above image the positive ions (Na, Mg, Ca) transfer their electrons to the negative ions (Cl, O, Cl)? And now they all have full shells!

(Non-Polar) Covalent Bonding

• bonding between 2 negative ions
• non-polar bonding is when the 2 ions share their electrons equally in order to obtain full shells
• this bonding occurs because the atoms are attracted to the nucleus of each other
• non-metals have a big electronegativity, therefore covalent bonding is really strong difficult to break

In the above image the negative ions are sharing the same number of electrons with each other!



Although electrostatic force is the force holding particles together, there are different forces in the structure of the molecule:

Intramolecular force - force that holds the atoms in a molecule

Intermolecular force - force that holds molecules together

                          

Organic Chemistry Naming: Part 1 of Many

Alkanes

You may be unaware that you use alkanes all the time.  Some examples are the the fuels you use everyday.

This is propane and methane(being released).

Alkanes serve many purposes.  They can be used as a plant hormone, in the production of polymers, and in components of gasoline.  

Alkanes are also saturated hydrocarbons(compounds containing only Carbon and Hydrogen).  You can easily remember this because the prefix "hydro" means water(even though the compound has no Oxygen there are still Hyrogen atoms).  Seeing that the word carbon is already in the word, it doesn't get any more obvious.  Saturated means that the molecule contains the maximum number of hydrogen atoms.  Recall that carbon has 4 valence electrons available to bond.  An example is ethane. 



Note that all the atoms have full valence shells because they are sharing electrons. 

Single bonds are represented by dashes.

In alkanes, carbon atoms only form single bonds.  This means that two electrons are being shared between the two carbons.

The general formula of an alkane is CnH(2n + 2).  Cn represents the number of Carbon atoms in the chain.  H(2n +2) represents the number of H atoms in the molecule.  For example, in butane, there are 4 carbon atoms.  How many Hydrogen atoms are attatched to this structure? Use the equation '2n + 2'.  Therefore, there will be 10 Hydrogen atoms.  The molecular formula is C4H10. 



Butane: like the previous example, all the shells are full.

Another way to write this molecule(structural formula) is CH₃CH₂CH₂CH_3.
Because all the hydrogens have equal charges, the bond angles are always 109.5°(tetrahedral).

Naming Alkanes

The naming rules of organic compounds has been determined by IUPAC. 

To name them you first have to identify the longest chain of continuous carbons. It does not need to be straight, as long as it is the longest and isn't interupted.  

Next count the number of Carbon atoms in the chain.  Use the chart to determine the prefix.  Say there are 6 Carbons, the prefix will be 'hex'.  9 Carbons; the prefix is 'non'.

To specify that the compound is an alkane, and the suffix 'ane'.  It's easy to remember because the ending of 'alkane' is also 'ane'.

Note: This is called a homologous series.

For example:

1)Count: 5 Carbons. 

2)Look on list: prefix 'pent'. 

3)Add 'ane'. 

4)Name: pentane.

 

Let's do another.



Each vertice represents a Carbon atom.  Like before, the lines all represent single bonds.

1) Count: 9 Carbons.
2) Refer to list: prefix 'non'.
3) Add 'ane'.
4) Name: nonane.
5) Check.  Is there anything else attatched to the structure? No.

To see some chemical reactions involving alkanes, swatch the following video.
Combustion of Alkanes

Organic Molecules- We Can Easily Survive Without Them Right?

In our world, we are heavily dependant on organic compounds.  Some examples(out of millions) include: DNA(we wouldn't be here without it), petroleum products: gas and plastics (if we didn't have it, at least it would save us from worrying about rising gas prices), and alkaloid crystalline compounds like caffeine(what would people look like in the morning?). 

SO WHAT ARE ORGANIC COMPOUNDS?
They are compounds that contain carbon.  Organic chemistry is the study of these compounds.

CARBON: Think of a carbon atom like a person.  He/she will be extremely friendly; they can each form 4 single bonds, or 2 double bonds, or 1 triple bond.

Reminder:

Single bond: bond between 2 electrons(shared)

Double bond: bond between 4 electrons(shared)

Triple bond: bond between 6 electrons(shared)

Carbon atoms are very versatile.  They form groups with all sorts of elements.  There are so many possible compounds that they can form.  They even have a whole branch of chemistry dedicated to them!  Some of the common groups they form are amines, alkyls, alkenes, esters, ethers, carboxylic acids, ketones, aldehydes, and alcohols.

 amine (histamine)

alkyl (used in detergent production)

 carboxylic acid (common household items)

ester (pineapple smell)

 ether (aerosol spray propellant)

 ketone (antibiotic)

aldehyde (glucose)

alcohol (rubbing alcohol)

To learn more about carbon and how it causes global warming, watch this video.

NPR- Episode 1- It's all about carbon

General Characteristics

Carbon forms mostly non-polar compounds(charges are equally shared).  It does not form ions.

As well most carbon compounds have low solubility in water.  This means that they do not easily dissolve in water.  As the number of carbon atoms in a molecule increases, the compound's water solubility quickly decreases. 

They are also non-electrolytes.  They do not conduct electricity well when dissolved in water. 

For more information, click on this link. 

Electrolyte Demonstration

Organic compounds generally have low melting and boiling points.  This is because the atoms are only attracted by the weakest form of intermolecular bonds. The bonds can be broken without using huge amounts of energy (in comparison to compounds formed with other types of bonds)

To see a fun video of what's to come this unit, watch the video below.

Organic Chemistry Song- Little Mermaid