Ketones and Aldehydes

A Ketone is a hydrocarbon chain, double bonded to an oxygen. The catch is that the double bonded oxygen CANNOT  be at the end of a chain, only in the middle.

When dealing with Ketones, we add the ending -one to the stem. Other than that, standard naming rules apply.

The Simplest ketone looks like this:


This is called Propanone (the Rs stand for hydrocarbons).

Ketones can be combined with other things like Alicyclics, Alkenes, Alkynes, and Aromatics.

For now, here are some more Ketones



The next one is Aldehydes!!!!

Aldehydes are just like ketones but the double bonded oxygens are on the end of the chain. To differentiate, we add the ending -al to the stem.

Like this:

this is 3 Methyl 1 Butanal



and this is 3,3, 5 Trimethyl Hexanal

There you  have it short and sweet :)

Alicyclics and Aromatics

Now that you have been thoroughly befuzzeled by double and triple bonds in organic chemistry, lets confuse you even more!!! Todays topics are Alicyclics ( circular bonds) and Aromatics( mostly benzene).


Before we start, lets just go over the three ways that you can draw organic compounds:

1) Complete structural diagrams



These can be rather time and space consuming.....

2) Condensed Structural Diagrams


These are somewhat easier

3) Line Diagrams


These are the most simplistic way of drawing organic compounds


Alicyclics are carbon chains that form loops. When they form the parent chain or the side chain, normal naming rules apply with the addition of the prefix cyclo- .

Lets try some examples:

This is the simplest alicyclic, cyclopropane.



When you have side chains as well, standard naming rules apply but you can start counting anywhere in the ring, provided you end up with the smallest numbers possible. The occasion can also arise that the Alicyclic will be the side chain itself in which case you simply add the cyclo- to the beginning and -yl to the end of the stem.

Now name these three!!!


Aromatics ( Benzene)

Benzene(C6H6) is a unique cyclic hydrocarbon. Benzene looks like this.....



The lines indicate a double bond. Basically because there are 6 carbons and 3 double bonds, each carbon has a 1.5 bond which sounds kind of confusing but it allows Benzene to do some cool things because its electrons are free to roam.

Benzene can be a parent chain ( called Benzene) or a side chain ( called phenyl). 

Pour example:


This woulod be called 1 Methyl Benzene...... or Toulene( theres no reason for this name, its " just what chemists do" quoth Doktor)

But this...



would be 3 Methyl 1 Phenyl Butane

Comprende?

Thats all for today folks.

Alkenes and Alkynes

Okay, so you now know the basics of Organic Chemistry and I'm sure your feeling pretty proud of yourself. Well that ends about now.
Since it wouldn't be any fun to have you think this is easy I'm going to throw a curve ball and make it harder for you. Aren't I nice
So you've figured out how to identify butane and methane and all those other compounds, but how about 2 butyne.
That is what I will be teaching you today.
 So I know you can identify this, it's 2 2 dimethyl propane, what I want to draw your attention to is those dashes ( - ) connecting the C to the CH₃'s. Those dashes represent a single bond.
And I'm sure your wondering what this has to do with anything, but there organic compounds aren't connected by only single  bonds their also connected by double and triple bonds. Like I said, wouldn't want this to be too easy for you.
Fortunately for you there isn't too much more tor remember when dealing with double and triple bonds,
here's what you have to know:
-ene  =  double bond
-yne  =  triple bond
when numbering the parent chain the double/triple bond takes the lowest number.

Also if there is more than one double/triple bond you put a multiplier in. For example hexatriyne.

And one more extra tidbit if two adjacent Carbons are bonded by double bonds and side chains there are only two possible compounds they could be.
Trans 2 butene or Cis 2 butene

Simple right? (or at least not too difficult)
Now lets try a few examples.
Name the compounds.
(I'll go through the first one with you)

First circle the parent chain

Then number the carbons 1-5 either from left to right or right to left (remember the double bond must have the lowest number)

 You can now name the compound.
The compound is (*drum roll*)
2 ethyl 1 pentene!

Now it's your turn (answers below)
1)

2) (this one doesn't have the Hydrogen's but you should get the idea)

3)

(Answers 1) 3 methyl 1 propyne, 2) 2 methyl 2 pentene, 3) 2 methyl 1 propene )

Happy naming
and of course to finish off a comic
(by the way the one asking if they look fat is glucose)

Organic Chemistry

A new unit, woohoo! This is veery interesting so far

Organic chemistry is the study of carbon compounds

-Carbon forms A LOT of covalent bonds (miiiiiiilllions, in fact)

While there are only less than 100 000 non-organic compounds, there are over 17 000 000 organic compounds!

Carbon compounds can form chains, rings or branches. The simplest organic compounds are made of carbon and hydrogen. The simplest is CH4, which is methane. It just has one C, and thus has 4 H's to fill all the bonds of the C.

Saturated compounds have no double or triple bond. Compounds with only single bonds are called Alkanes and ALWAYS end in -ane

Now, let's learn how to name these! There are three categories of organic compounds:

1) Straight chains

2) Cyclic chains

3) Aromatics

Today we'll do only straight chains!

Some ground rules for naming straight chains:

1) Circle the longest continuous chain and name this as 'the base chain'

2) Number the base chain so side chains have the lowest possible numbers

3) Name each side chain using the -yl ending

4) Give each side chain the appropriate number

5) List side chains alphabetically

This'll all make much more sense through the examples!

Unfortunately, drawing out examples is a bit impossible on here, so I won't be able to show step by step... but I will explain it!

The first thing you would do is circle the longest possible chain (without repeating the same one). In this case, there are a few options, but lets take the simplest one, which is the bottom three (the straight row). This row has THREE and the prefix for three is 'prop' and since it ends in -ane, give it the name propane for now. In this case, numbering it will work either way, because either way the side chain will be number 2. There is only 1 off the side chain, so the prefix before the -yl is 'eth', making it ethyl. You want to remember to number it though, so it's 2 ethyl. That means that the full name is 2 ethyl propane!

Congrats, you've just named your first piece of organic chemistry!

Polar and Non-Polar Molecules

Okay for polar vs. non-polar molecules there is only one really important thing you have to remember. If when drawing a molecular diagram the molecule is symmetrical the molecule is non-polar, therefore if the molecule is unsymmetrical the molecule is polar.

Symmetrical = Non-Polar

Unsymmetrical = Polar

If you still don't understand here is a good video that explains it.

Now you should understand the general idea, now tell me which of the following molecules are polar and which are non- polar. Also using electronegativity figure out which side is partially positive and which side is partially negative (hint: the one with the most electronegativity is partially negative)

1)

2)

3)

  

Answers: 1--polar, the left side is partially negative

               2-- polar, the bottom half is partially negative
               3--non-polar

The reason why non-polar molecules have no partially negative/partially positive side is because the pull of electrons is balanced.

Acid-Base Reactions

This is a relatively simple unit, so there aren't too many notes. Basically
Strong acids dissociate to produce H⁺ ions
Strong bases dissociate to produce OH^-  ions
However, when strong acids and strong bases mix you get HOH and ionic salt

And since you also know that pH is the measure of H ions present in a solution, you also probably know that pOH would be the measure of OH ions in a solution.
Thus
pH = -log[ H⁺ ]
pOH = -log [ OH^- ]

So here's an example to test you knowledge of the new concept while still incorporating past knowledge.

If  .100 L of .40M of HNO₃ is added to .300L of .20M of NaOH
First find the limiting reactant
0.1 x (.40mol)/(1L) x 1/1 x (1L)/(.20mol) = .2 L of NaOH is needed
(since you have .300 L of NaOH)  HNO₃ is the Limiting Reactant

Then find how much NaOH will be left over.
So you find how much NaOH you use, and how much HNO₃ you use.
(.3L) x (.2mol)/(1L) = .06 mol of NaOH used
(.1L) x (.4mol)/(1L) = .04 mol of HNO₃ used
You then subtract the amount of NaOH used from the amount of HNO₃ used
.06-.04 = .02 mol of excess HNO₃

Next find the pH
pH = -log [ H⁺ ]
      =  -log(.02)
pH = 1.7           (there are no units)

Not too difficult, right? Now if you can do a question like that then you fully understand Acid-Base reactions.
And just make sure you remember your significant digits and decimal points

Intermolecular Bonds

Today we studied two different types of bonds.

Intramolecular              and                        Intermolecular

Intramolecular Bonds exist inside molecules, for example Ionic and Covalent bonds.

Intermolecular Bonds exist between molecules and there are three different types.

1. London Dispersion Forces

These are the weakest intermolecular bonds. These happen in almost every molecule and are caused by the random movements of electrons inside atoms. Sometimes a large of electrons congregates on one side of an atom, causing a temporary dipole.




London Dispersion Forces at work......


2. Dipole-Dipole Bonds

These exist only in polar molecules, where the negative and positive ends of molecules are attracted to the negative and positive ends of other molecules. These are stronger than London Dispersion Forces but weaker than Hydrogen Bonds.




A Polar Molecule


3. Hydrogen Bonds

When Hydrogen bonds with certain elements( Oxygen, Fluorine, Nitrogen, and in some cases Chlorine). Hydrogen Bonds are very strong.




A Hydrogen Bond



We can measure how high or low the melting and boiling points of elements will be based on their bonds.


Thats all for today Celtics!!!



haha