Organic Compounds: Esters, Ethers, Carboxylic Acids, Amines

Organic Compounds: Esters, Ethers, Carboxylic Acids, Amines

An Ester. "R" represents a carbon chain.

Ethyl propanaote.

Esters are organic compounds that have two carbon chains seperated by a oxygen atom and a double bonded oxygen. The carbon chain that doesn't include the double bonded oxygen (R2 in this case) is named first and given an "yl" ending, like methyl. The carbon chain including the double bonded oxygen is then name by replacing the suffix "e" with an "oate". For example in the diagram to the right the chain without the double bonded oxygen is simply named ethyl. The chain with the double bonded oxygen is then named propane for a carbon chain of three and then the suffix "e" is replaced with "oate" giving propanoate. Bringing both together gives the name "Ethyl propanaote".

Methoxyethane

Ethers are when a carbon chain is seperated by an oxygen atom and no double bonds. For naming, the shortest carbon chain seperated by the oxygen is named first and give the suffix "oxy" instead of "ane". Then the longest chain is named normally. In the diagram above the shortest chain is methane so it becomes methoxy. The other carbon chain is ethane and stays the same. Bringing the two components together the name becomes Methoxyethane.





Carboxylic acid. "R" represents a carbon chain.

Carboxylic acids are carbon chains with a double bonded oxygen and OH connected to a carbon atom at the end of a carbon chain. The suffix "e" is changed to "oic acid". For example if there is a carbon chain of four the name would be butanoic acid.

An amine. "R" represents a carbon chain

Amines are when NH2 are connected to a carbon chain. When the NH is at the end of the carbon chain the name is the carbon chain with "yl" suffix and amine after it. Though if the the NH is in the middle of the chain you can name the position with a number and put "amino" as a preffix.

Organic Compounds: Cyclo, alkanes, alkenes, and alkynes

Organic Compound
(butene)

Organic Compounds: Cyclo, Alkenes, Alkanes, Alkynes

When naming basic organic compounds you need to know the prefixes for the number of carbons present in the longest chain.

In the above diagram on the left the names for each chain of carbons are written. These are the names of organic compounds that have one to ten carbons atoms in a single chain. If the ending of "ane" is changed to an "ene" (double bond) or "yne" (triple bond) it tells you that a carbon atom in the chain is sharing more than one electron with a carbon near it.

Butene Line diagram

In the above diagram is a Butene molecule (line form). To name this you look for the longest chain of carbons (which is four) giving you the base name of Butane. Then you realize that there is a double bond at the second carbon atom (remember to make the number you counted from as small as possible within the compound) so you put a 2 infront of the butane and replace the "ane" with a "ene" meaning that there's a double bond. The end result should be 2-Butene.

Cyclopentane

When naming a cyclo (a circular organic compound) you first need to find out if the cyclo portion has the longest chain of carbons within it or if that it is connected to another chain of electrons. If it is the main chain its easy as counting the carbons present in the chain and naming that if its an alkane, alkene or alkyne and putting cyclo infront of it. Like in the diagram above it can be seen that there are five carbons so the base name is pentane and since there are no double bond you can just say Cyclopentane. If the cyclo is just an addition the main carbon chain you just state the position of the clyclo with a number and then state how many are in the cyclo and name the rest of the compound normally.

methylbutane

Also when naming organic compounds there can be side chains of elements (in this case carbons). These are easily named by looking at how many are in the side chain and naming it accordingly; in the digram above there is one carbon in the side chain so you can write methane and since its a side chain instead of "ane" you write yl. These leaves you with 2-methylbutane.

Organic Compounds: Halides, Nitro, Alcohol, Keytones, and Aldehydes

2-Chloropropane

Organic Compounds: Halides, Nitro, Alcohol, Ketones, and Aldehydes

Beginning naming with halides(the above diagram), Halides are the halogens like chlorine, flourine, bromine, etc.. Its easy to name a compound with a halogen in it, all that needs to be done is to count the position on the main carbon chain and then to alphabetalize the things that come before the name of the carbon chain. When naming the halogen in the organic compound's name, remove the "ine" and replace it a "o". For example in the above diagram you have propane and a chlorine on the second bond; so it's simply named 2-chloropropane.



Nitromethane

Organic compounds can also include nitrite. When nitrite is connected to a carbon chain it has the same naming as halides except the "ite" is replaced with "o" giving you nitro. The naming is similar. In the diagram above there is a methane and a nitrite connected to it. Naming this is nitro for nitrite and methane, giving the name Nitromethane.



3-pentanol

Compounds including OH are classified as Alcohols. Naming alcohols changes the name of the carbon chain. The "e" at the end of the name of a carbon chain is removed and replaced with an "ol". For example in the above diagram the main carbon chain is pentane and there is a OH at the third carbon. So the name is 3-pentanol.

"R" represents a carbon chain

Ketones are when an oxygen atom that is double bonded to a carbon is connected to a carbon chain in the middle. Naming is as easy as numbering the position and removing the "e" in the suffix of the main carbon chain. If the carbon chain already had a change from the "ane" suffix "oxo" can be added to the beginning of the carbon chains name instead.

"R" represents a carbon chain

Aldehydes are when an oxygen atom is at the end of a carbon chain. Replacing the suffix "e" of the carbon chain and replacing it with "al" will give the compounds name. For example pentanal. Pentanal would have five carbon atoms connected by single bonds and one double bonded oxygen at the end.

VSEPR

Basic VSEPR configurations

VSEPR

Molecules are not flat in real life. They are three dimensional figures if they could be seen. Depending on the elements present and how many of each different Geometric shapes can be made from them. These geometric shapes vary but all share the idea that the angles between the electrons and atoms around a center element can be calculated.


water VSEPR

In the above diagram the Hydrogen atoms are 104.45 degrees away from each other and 127.75 degrees from the electrons of oxygen.

Chemical Bonding

Water molecule (H2O)




Chemical Bonding

The bonding of elements can be catagorized into either ionic or covalent. In an ionic compound the electrons are simply given from one element to another leaving one element positive and the other negative because of the shift of electrons.


Ionic bond of chlorine and sodium



As can be seen in the diagram the electrons from the valence shell are given to another element giving both elements a full valence shell. Covalent bonds are when electrons are shared. Depending on the electronegativity of the elements present the bond can become polarized. For example in water (the first diagram), oxygen has a higher eleconegativity and becomes slightly negative while the hydrogens become slightly positive. For covalent bonds inbetween the same elements or similar electronegativities the elements in the compound don't become polarized.

For a video reference go to: http://www.youtube.com/watch?v=QqjcCvzWwww

Bohr and Lewis electron dot diagrams

Bohr and Lewis electron dot diagrams

Bohr and Lewis diagrams are diagrams of elements that the valence electrons for each element are drawn. These electrons are the electrons that are shared or given away in covalent and ionic compounds. They include the "s" and "p" energy list. To draw a dot diagram you write the symbol for and element and draw a dot for evey valence electrons not putting two electrons beside each other until all sides of the element at least have one.



Lewis Diagram of Chlorine

For a video reference: http://www.youtube.com/watch?v=y6QZRBIO0-o

Electronegativity and Polarity

(Red being the most electronegavite and yellow the least)

Electronegativity and Polarity

Electronegativity is the tendency of an element or atom to attract a bonding pair towards itself in a compound. It can range anywhere between 4(fluorine) and 0.7(francium). The higher the number the more likely that electrons will be pulled towards that element in a compound. When a compound is formed with two different elements depending on the electronegativity the elements become polarized. The symbols + and - mean "slightly positive" and "slightly negative". You read + as "delta plus" or "delta positive". The more electronegative element becomes slightly negatively charged while the less electronegative element becomes slightly positive.

In the compound of Carbon and Fluorine, the more electronegative Fluorine attracts the electron pairs and becomes slightly negative and with the carbon is left with less electrons near it becomes slightly positive.

For more insight try this link: http://www.youtube.com/watch?v=Kj3o0XvhVqQ

Periodic table Trends

Periodic Table Trends

The Periodic Table has more trends than just the similarities in properties of elements in each column. Other trends are present like atomic radius, ionization energy, eletron affinity, and electronegativity. As can be seen in the image there are many trends on the periodic table.

Atomic radius is the distance between the outter most electrons and the nucleus. Since the farther down you get on the periodic table the more energy levels are present in the atom, there is a tendency as you move down and to the left on the periodic table to have a higher atomic radius.

Ionization energy is the amount of energy to remove the outter most electron of an atom. When this happens the atom becomes an ion and is positively charged. As you get closer to the top right the more energy you need to remove the outter most electron resulting in a higher ionization energy.

Electron affinity is the amount of energy when an electron joins onto an atom. Electron affinity is not as clear as ionization energy but as you go to the top right of the periodic table electron affinitiy increases.

History of the Periodic Table

History of the Periodic Table



The periodic table shows all the known elements in order of atomic number. Even though the elements listed on the periodic table haven't changed themselves the periodic table has. By 1869 a total of 63 elements had been discovered, and were arranged according to their properties and gaps were left where elements were thought to be missing. The scientist Dimitri Mendeleev was the first to publish a periodic table.



Though the 1869 periodic table looks drstically different than the current day periodic table the elements each have their atomic number and "?" are left where there are elements missing. As more elements were discovered in the 20th century the periodic table became more refined to what it is today.

Electronic Structure of the Atom

Electronic Structure of the Atom Including Electron Configuration and Valence Electrons

Depending on how many electrons an atom has there is a set pattern that the electrons conform to. For each energy level there is a maximum amount of electrons that can be in them. For the "s" there can only be two electrons, "p" can have six elecrtrons, "d" can have ten electrons, and "f" with the most energy can have fourteen electrons within it. For instance elements within the second row of the periodic table can have their electrons written out as 1s^2 2s^2 2p^6.

Along side the electron configuration valence electrons are introduced. These are the electrons in the outter most, uncomplete shells of the "s" and "p". The electrons in these uncomplete energy levels are the electrons that are used in ionic and coavalent compounds. Also since only the "s" and "p" energy levels are taken into account for the valence electrons the maximum amount of electrons in the valence shell is eight.

Structure of the Atom

Structure of the Atom

An atom consists of neutrons, protons, and electrons. Protons are positively charged and electrons are negatively charged. The electrons orbit around the nucleus, that consist of protons and neutrons.

In terms of mass, neutrons and protons contribute the most to the total mass of an atom. Electrons, in comparison to the neutrons and protons in the nucleus, don't affect the total mass of the atom.

History of the Atom

History of the Atom

Around 460 B.C.E. a Greek philosopher Democritus first questioned the existence of atoms. He thought the atom was a sphere with barbs on the surface that held it together with other atoms. Not until about the 1800's though did the idea of the atom become revised. John Dalton was the first modern scientist to look at the fact that matter was made up of atoms.

J.J. Thomson's atomic model

In 1897 J.J. Thomson discovered the electron and proposed the "Rasin in Pudding" model of the atom. It showed a sphere with electrons attached on the outside in random posistions.

 Ernest Rutherford's atomic model

In 1911 Ernest Rutherford sent alpha rays from Radium through gold foil and discovered most of the rays went through the foil. He then brought him to believe that in an atom there are empty spaces between the electons and the nucleus.

Niels Bohr's atomic model

In 1912 Niels Bohr stated a theory of why electrons did not spiral into the positive part of an atom and stated that electrons occupy shells around the nucleus.

Excess and Limiting Reactants Percent Yield

One reactant is the excess quantity and some of it will be lefy over. The second reactant is used up completely, and is the limiting reactant.

Here's the step to find the excess and limiting reactants:
Step1. Balanced equation
Step2. Convert one to another

and then you can find which one is left over. The one has more is excess reactants and the one that has less is limiting reactants

Here's a video that show an example and clearly explain about excess reactants and limiting reactants:

Percent Yield

Percent yield is the amount of product that is produced during an experiment verse the theoretical amount produced when using stoichiometry. It is simply the amount of product produced divided by the thereotical amount found by using stoichiometry then multiplied by 100% to find the percent.

If you have a theoretical value of 5 grams of water produced but only 3 grams produced when the actual experiment is done you simply divide 3 by 5 and then multiply by 100% to get a 60 percent yield.

The following video is similar to what we explain earlier:

Stoichiometry

Stoichiometry is can be thought of the ratio of moles in a chemical reaction between the reactants and products. The coefficients in a balanced equation tell you the ratios and with this you can find how much of each element or compound is produced theoretically.

For example:

2H2 + O2 -> 2H2O

If you have 10 grams of Hydrogen (H2) you can find out how much water is produced with sufficient amounts of Oxygen.


By simply converting to moles (10 grams of H2 is 10/2 or 5 moles of H2) and then transferring to the other side you will know that you get 5 moles of water and that converted to grams is (5x18=90) 90 grams.

So in one step its:

10 grams of H2 x 1mol/2grams x 2H2O/2H2 x 18 grams / 1mol of 2H2O = 90grams

Here is a video that explain stoichiometry:

Energy Calculations

Energy Calculations

The energy of absorption or release depends on each equation

Exothermic reactions have the energy on the right hand side and a negative H

Endothermic reactions have the energy on the left hand side and a positive H

H is the energy of charge of a reaction and is expressed in JK per mole of the chemicals

CH4+2O2 à CO2+2H2O+812KJ

-812/1mol CH4

-812/2mol O2 (-406)

-812/1mol CO2

-812/2mol 2H2O (-406)

0.45 mol H2O * -812/2mol 2H2O = -190KJ

2500 energy release

 -2500*1mol CH4 / -812 = 3.1mol of CH4

How many gram of O2 would needed to produce 2500KJ of energy?

-2500* 2mol O2/-812 = 6.2 moles of O2

6.2 moles of O2 * 32g/1 mol = 200 of O2

Translating Word Equation/ Naming Compound

Translating Word Equation/ Naming Compound

Ionic Compound

Metal stay the same and non metal has to add “ide” in the end

LiCl à Lithium Chloride

BeS à Beryllium Sulphide

PbF4à Lead(IV) Fluoride

Covalent Compound

We put word in front of non metal for different number

1-      Mono

2-      Di

3-      Tri

4-      Tetra

5-      Penta

6-      Hexa

7-      Hepta

8-      Octa

9-      Nona

10-  Deca

11-  Hendeca

12-  Dodeca

We put everything except mono for the non metal in the front.

Everything for non metal in the back

Acids

HCL          Hydro Chloric acid

H2SO4      Sulphuric acid

H2SO3            Sulphurous acid

Ate à ic

Ite à ous

Lab- 5B

Lab- 5B

Objective:

1. To observe a variety of chemical reaction

2. To interpret and explain observations with balanced chemical equations

                3. To classify each reaction as one of the four main types

Reaction 1:

       

Adjust a burner flame to high heat.

Using crucible tongs, hold a 6cm length of bore copper wire in the hottest part of the flame for a few minutes

Changes during: it starts to change color

Changes after: it turns to black

Equation- Cu+O2 à 2CuO (synthesis)

Reaction 2:

       

Clean an iron nail with a piece of steel wool so the surface of the nail is shiny

Place the nail in a test tube and add copper (II) sulfate solution so that one half of the nail is covered

After approximately 15 mins, remove the nail and note any changes in both the nail and the solution

Changes during: liquid starts to turn green and bubbles all over the nail

Changes after: liquid becomes green

Equation- 3CuSO4 +2Fe à Fe2 (SO4) + 3Cu (single replacement)

Reaction 3:

Put some solid copper (II) sulfate pentahydrate in a test tube so that it is 1/3 full

Using the test tube clamp to hold test tube, heat the test tube, moving it back and forth gently over burner flame

        Continue until there’s no further change is observed

Changes during: smoke appear

Changes after: It turns white

Equation- CuSO4 .5H2Oà CuSO4 +5H2O (decomposition)

Reaction 4:

Allow the test tube contents from reaction 3 to cool

Use medicine dropper to add 2 or 3 drops of water

       

Changes during: change color, heated

Changes after: turns black to blue

Equation- CuSO4 +5H2Oà CuSO4 .5H2O (synthesis)

Reaction 5:

Allow the test tube one quarter with calcium chloride solution. Fill a second test tube one quarter full with sodium carbonate solution

Pour the calcium chloride solution into the test tube containing sodium carbonate solution

       

Changes during: smoke it’s a fast reaction, turn white after added together

Changes after: white solid and becomes milky

Equation- CaCl2 (aq) +Na2CO3 (aq)à 2NaCl2aq) +CaCO3(s) (double replacement)

Reaction 6:

Place a piece of mossy zinc in a test tube

Add hydrochloric acid solution to the test tube until the mossy zinc is completely covered

       

Changes during: zinc starts to get less, bumbles starts to appear

Changes after: zinc disappears, liquid turns a little white

Equation- 2HCl+Znà ZnCl2+H2 (single replacement)

Reaction 6:

Half fill as a test tube with hydrogen peroxide solution.

Add a small amount of manganese (IV) oxide

Test the evolved by placing a glowing splint into the mouth of the test tube

       

Changes during: Bubbles occurs

Changes after: the blowing splints burning again

Equation- 2H2Oà(MnO2) 2H2O+ O2 (decomposition)

Endothermic and Exothermic

Every reaction also has an exchange of energy either endothermic or exothermic. Endothermic means the reaction takes in the energy around it. Exothermic means that energy is realeased by the reaction.


This is a graph of an Endothermic reaction.

This is an Exothermic reaction:

There is a very subtle difference between the two, in the endothermic the product has more energy than the reactants and in the exothermic reaction the product has less energy. Aside from the the same thing happens, enough energy is needed to get the reactant to the activated complex ( the activation energy) and then depending if the reaction is endothermic or exothermic energy is left in the product or given off. The difference of the energy in the product and the reactant is the ∆H  and is positive only if the reaction is endothermic and negative when the reaction is exothermic.

Also when writing up chemical reactions enegry can be included to show how the reaction works.

For example:

AB + 125kJ -> A + B

Types of Reaction and Balancing Equation

Balancing Equations

The number of atoms the reactant side = the product side.

1.      Balance the atoms only occur in one molecule on each side of equation

2.      Don’t considering atoms separately, Balance whole groups whenever possible

3.       Don’t jump all over an equation, balancing a bit here and a bit there. Be systematic

4.      Balance atoms which occur in elemental form last. By elemental form we mean that the atoms are not combined with any atoms of a different kind

Li+ MgCl2 -> LiCl +Mg

Balance: 2Li+ MgCl2 -> 2LiCl +Mg

An equation isn’t properly balanced until we have actually balance both side

Ionic Compounds

Na SO4   Sodium Sulphate

K2Cl   Potassium Chloride

Fe2S3   Iron (III) Sulphide

Covalent Compound

1= mono, 7= hepta

2= di    8= octa

3= tri    9= nona

4= tetra  10= deca

5= penta 11= hendeca

6= hexa  12= dodeca

Acids

HCl= Hydro Chloric acid

H2SO4= Sulphurous acid

Types of Reactions

1.      Synthesis

It’s a reaction that combines 2 or more reactants to from one product

X+Y -> Z

Na+Cl-> NaCl

2.      Decomposition

It’s a reaction that breaks down one reactant in to 2 or more products

XY-> X+Y

NaCl-> Na+Cl

3.      Single replacement

It’s one where an element replaces an ion in a ionic compound. Metal replace positive ions (cations) and non metal replace negative ions (anions)

X+YZ-> XZ+Y (X= metal)

X+YZ-> ZY+Z (X= non mental)

2Al+ 3CuCl2-> 2AlCl3+ 3Cu

Predicting Single replacement reactions

Some metals are more reactive than other metals. So the metal has to be higher than the replace one to have reactions. Apply to both metals and non metal

Fe+ ZnCl2-> NR (because Fe isn’t more reactive than Zn)

3Mg+ 2AlCl3-> 3MgCl2+ 2Al (Yes because Mg is more reactive than Al)

4. Double replacement

A double replacement is a reaction between 2 ionic compounds usually in solution

WX+YZ-> WZ+XY

K2CO3+BaCl2-> 2KCl+ BaCO3

If the reactants change start during the reaction, this is a reaction occurring (usually precipitate forming)

If there’s no change of state, then there’s no reaction

Use “Table of Solubilities” to determine the states –(aq) or (s)

5. Combustion

It’s a reaction where burning in air is involved. The reactants are the chemical to be burned and the oxygen that it reacts with. The oxygen usually ends up combine more than one type of atoms as products.

AB+O2-> AO+BO

C4H8+6O2-> 4CO2+H2O

6. Neutralization

It’s a special double replacement reaction where acid react with bases to produce water

The acids have an H (+) as the cation and the bases have OH as the anion (-). Both should be (aq)

HA+BOH-> H2O+BA

        2HBr+Sr (OH) 2-> SrBr2+ 2H2O