Alkenes & Alkynes

A. Carbon can form double and triple bonds with carbon atoms.

 B. Naming rules are almost the same as with Alkanes (single bond chains)

                a. Double bonds end in "-ene"

                b. Triple bonds end in "-yne"

                c. When numbering the base chain, double/ triple bonds always get the lowest number

 ex. 

Name: 4 Methyl 2 Pentene

ex.

Name: 4, 4 Dimethyl 4 Heptyne

ex. 

Draw 2, 3, 4 Trimethyl 1 Octene

Trans & Cis Butene

A. If 2 adjacent carbons are bonded by a double bond AND have side chains on them there are 2 possible compounds. 

     a. Cis: The side chains are on the same side as the base chain

Cis 2 Butene

     b. Trans: The side chains are on opposite sides of the base chain

Trans 2 Butene

Multiple Double Bonds

A. More than 1 double bond can exist in a molecule

B. Use the same multipliers inside the base chain name

ex. 

 1,3 Butadiene

ex. Draw 2 methyl 1,4 pentadiene

Polar and Non-Polar Solvents Lab

Objective: To determine if glycerin is Polar or Non-polar

Materials:

·         Test tubes

·         Test tube stoppers

·         Test tube rack

·         Scupula

·         Safety goggles and apron

·         Sodium chloride

·         Sucrose

·         Iodine crystals

·         Paint thinner (Turpentine)

·         Glycerine

Part 1

Procedure:

1.       Set up 6 clean, dry test tubes. Divide the test tubes into 2 groups of 3. Label a piece of paper in front of each pair A, B, and C.

2.       Fill each test tube from the first set half way with water. Fill each test tube from the second set half full with paint thinner.

3.       In the first set, carefully add enough salt crystals to cover the bottom of the test tube.

4.       Stopper the test tube and carefully shake it several times. Examine the test tube and look for any crystals that may be stuck against the walls. Repeat this process with the first test tube in the second set.

5.       Repeat steps 3 and 4 with crystals of sugar in test tube B from each set.

6.       Repeat steps 3 and 4 with crystals of iodine in test tube C from each set.

7.       Dispose of the test tube solutions in the Waste Chemical container.

Observations:

Solvents	Solute	Solute	Solute
	Table Salt	Sugar	Iodine
Water	Dissolved	Dissolved	Did not dissolve
Paint thinner	Did not dissolve	Did not dissolve	Dissolved

Part 2

Procedure:

1.       Fill a clean test tube a quarter way full of water and then add twice as much paint thinner to the test tube.

2.       Stopper the test tube and shake it gently.

3.       Examine what has happened to the solutions.

4.       Using a second test tube, repeat steps 1 through 3 using Glycerin in place of paint thinner.

Analysis:

1) Based on the results from part 1, what conclusions can you draw about the types of solutes that can dissolve in polar and non-polar substances?

Polar substances dissolve polar solutes.

Non-polar solutes dissolve in non-polar substances.

2) Using the conclusion you made in question 1, predict whether or not Glycerin is polar or non-polar.

Glycerin is polar because it did not dissolve.

3) What would you predict to happen if you combine water, glycerin and paint thinner all in one test tube.

The glycerin will dissolve in the water and the paint thinner will float on top.

Organic Chemistry

I. Organic chemistry is the study of carbon compounds

                A. Carbon forms multiple covalent bonds

                B. Carbon compounds can form chains, rings, or branches

                                a. There are less than 100 000 non-organic compounds

                                b. organic compounds make up 400 000 compounds

                C. The simplest organic compounds are made of carbon and hydrogen

Expanded structural diagram

Condensed structural formula:

1 3-dichlorocyclopentane

III. Saturated compounds

                A. Have no double/ triple bonds

                B. Compounds with only single bonds are called alkalines and always end in "-ane"

IV.  Nomenclature

                A. There are 3 categories of organic compounds

                                                a. straight chains

                                                b. cyclic chains

                                                c. aromatics

                B. Straight chains

                                a. Rules for naming straight chain compounds

                                                1. Circle the longest continuous chain of carbons. This is your base chain.

       2. Name this base chain using the following chart and adding the ending "-ane"

Number of Carbon Atoms	Stem Name	Side Chain Name	Multiplier
1	Meth	Methyl
2	Eth	Ethyl	Di
3	Prop	Propyl	Tri
4	But	Butyl	Tetra
5	Pent	Pentyl	Penta
6	Hex	Hexyl	Hexa
7	Hept	Heptyl	Hepta
8	Oct	Octyl	Octa
9	Non	Nonyl	Nona
10	Dec	Decyl	Deca

In this case the name of the base chain is: Butane

      3. Number the base chain so that the side chains have the lowest possible number    

           4. Name the side chain using the appropriate stem name and the ending "-yl"

The side chain in this example is called: Methyl

          5. Give the side chain the appropriate number

The side chain in this example is now called: 2 Methyl

          6. If there is more than 1 side chain repeat steps 4 and 5 and list the side chains                                                                 in alphabetical order

THE COMPLETE NAME FOR THIS STRAIGHT CHAIN IS: 2 METHYL PROPANE

Types of Bonds

A. Intramolecular: bonds that exist within a molecule

                -ionic, covalent

B. Intermolecular: bonds that exist between molecules

                -the stronger the intermolecular bonds the higher the boiling point or melting point

                -2 types of intermolecular bonds: Van der  Waasl bonds and hydrogen bonds

I. Van der Waals Bonds

                A. Based on the electron distribution

                                a. 2 categories

                B. Dipole-dipole bonds

                                a. If a molecule is polar the positive end of one molecule will be attracted to the negative end of another molecule

II. London Depression Forces (LDF)

                A. present in all molecules

                B. creates weakest bonds

                C. If a substance is non-polar, dipole-dipole bonds do not exist, only LDFs

                D. Electrons are free to move around and will randomly be grouped on one side of the molecule

                E. This creates a temporary dipole and can cause a weak bond to form

                F. The more electrons in the molecule the stringer the LDF can be

IV. Hydrogen Bonding

                A. If hydrogen is bonded to certain elements (F, O or N) the bond is highly polar

                B. This forms a very strong intermolecular bond 

Polar Molecules

I. Polar Molecules
                A. Have an overall charge separation

                B. Unsymmetrical molecules are usually polar

                C. Molecular dipoles are the result of unequal sharing of electrons

II. Predicting Polarity

                A. If a molecule is symmetrical, the pull of an electron is usually unbalanced

                B. Molecules can be unsymmetrical in 2 ways

                                a. different atoms

                                b. different number of atoms

Bonding

I. Types of Bonds

                A. There are 3 main types of bonds

                                a. Ionic (metal and non-metal)

                                                i. electrons are transferred from metal to non-metal

                                b. covalent (non-metal and non-metal)

                                                i. electrons are shared between non-metals

                                c. metallic (metal and metal)

                                                i.holds pure metals together by electrostatic attraction

II. Electronegativity

                A. Electronegativity (en)* is a measure of an atom's attraction for electrons in a bond

                B. Atoms with a bigger en attract/want electrons more

                C. Polar covalent bonds form from an unequal sharing of electrons

                D. Non-polar covalent bonds form from unequal sharing of bonds

III. Bonds

                A. The type of bond formed can be predicted by looking at the difference in electronegativity of elements

                                a. en > 1.7 = ionic bond

                                b. en < 1.7 = polar covalent bond

                                c. en = 0 = non-polar covalent

bond

Ion Concentrations

I. Dissociation

                A. Ionic compounds are made up of 2 parts

                                a. Cation: positively charged particle

                                b. Anion: negatively charged particle

                B. When ionic compounds are dissolved in water the cation and anion separate from each other. This process is called dissociation

                C. When writing dissociation equation the atoms and charges must balance

                                a. The dissociation of sodium chloride is:

                                NaCl ---> Na⁺ + Cl^-

Ex. Complete the following dissociations

1. Fe(OH)₂ ---> Fe²⁺ + 2OH^-

2. Na₃PO₄ ---> 3Na⁺ + PO₄^3-

3. Fe₃(PO₄)₂ ---> 3Fe²⁺ + 2PO₄^3-

                        D. If the volume does not change then the concentration of individual ions depends on the balanced coefficients in the dissociation equation

Ex. Determine the [Na⁺] and [PO₄^3-] in a 1.5M solution on Na₃PO₄

Na₃PO₄ -->  3Na⁺ + PO₄^3-

1.5M x (1/1) = 1.5M [PO₄^3-]

1.5M x (3/1) = 4.5M [Na⁺]

Ex. Determine both ion concentrations when a 2.5M solution of Lithium sulphate dissociates.

Li₂SO₄ ---> 2Li⁺ + SO₄^2-

2.5M x (2/1) = 5.0M [Li^-]

2.5M x (1/1) = 2.5M [SO₄^2-]