UNIT 1 – ORGANIC CHEMISTRY

Organic chemistry: study of compounds that are based on carbon. ◦ Usually contain carbon-carbon and hydrogen-

carbon bonds.

Chapter 1Classifying Organic Compounds

The Carbon Atom usually forms a total of 4 covalent bonds. Can form strong single bonds (_____ pair(s)

of electrons shared, double bonds (_____ pair(s) of electrons shared), or triple bonds (______ pair(s) of electrons shared) with other carbons.

Saturated molecules: carbon atoms have maximum bonding capacity of __________.

Molecules containing double or triple carbon-carbon bonds are called ________________.

Common Molecular Shapes in Organic Molecules

Rules for drawing a 3-D molecule◦ Let’s use methane, CH4, as an example.◦ “Wedges” are used to give the impression that an

atom or group is coming forward.◦ Dashed/dotted lines are used to show that an

atom or group is receding.

3-D Structural Diagrams

Relate this to electronegativities...

Which of the following bonds are polar? Non-polar?

C – O O – H N – H

C – C C -H

Polar Molecule: molecule has an overall imbalance of _________________.

Not all molecules with polar bonds are polar molecules. (e.g. CO2 has two polar C=O bonds, but is not a polar molecule).

Is water a polar molecule?

Predicting Molecular Polarity

1) If equal bond dipoles act in opposite directions in three-dimensional space, they counteract each other. The molecule is _________________________.

E.g. CCl4,

(four identical dipoles, pointing toward the vertices of a tetrahedron, counteract eachother can prove mathematically)

RULE 1

If the bond dipoles in a molecule do not counteract each other exactly, the molecule is _________________.

E.g. Water

E.g. CHCl3 , chloroform

(bond dipoles do not act in opposite directions, therefore, do not counteract each other, and molecule is polar).

RULE 2

CLASSWORKRead page 9, steps 1, 2 and 3. Create a dichotomous key in order to

determine the polarity of the molecule, with one example at each ‘end’ of each ‘branch.’

Read sample problem, pg. 10, and doPPs # 1-4

Steps for Predicting the Polarity of a Molecule

Page 11, #2, 4, 5

Section Review

Hydrocarbons: simplest type of organic compound. ◦ Composed entirely of hydrogen and carbon. ◦ Widely used as fuels. E.g. Gasoline, propane, and

natural (non-polar). Aliphatic: carbon atoms bonded in one or

more chains and rings. Single, double, triple bonds.

Aromatic: based on aromatic benzene group (later!)

1.2 – Hydrocarbons

Alkane: single bonds.◦ Linear: CnH2n+2◦ Cycloalkane: CnH2n

Alkene: at least one double bond.◦ Linear with one double bond: CnH2n.

Alkyne: at least one triple bond. ◦ Linear with one triple bond: CnH2n-2.

Alkanes, Alkenes, and Alkynes

Double and triple bonds contain more than one bond.

First bond is always strongest. Second and third bonds are weaker:

therefore, react faster◦ C=C bonds are ________________________ than C-C

bonds.

The Strengths of Bonds

Functional Group: reactive group◦ Each group helps to determine the physical and

chemical properties of compounds. ◦ E.g. Reactive double bond of an alkene is the

functional group.

Functional Groups

The International Union of Pure and Applied Chemistry (IUPAC) has standard rules for naming organic compounds

PREFIX + ROOT + SUFFIXRoot- Number of carbons in the main chain/ring.

Suffix- Depends on functional group present.- E.g. –ane, -ene, and –yne. (there are many others)Prefix- Indicates the name and location of each branch and functional

group in the main carbon chain. - Alkyl groups: branches on main chain.

Naming Organic Compounds

1) Find the root: identify the longest chain or ring. - If cyclic compound, add prefix –cyclo- before the root.

2) Find the suffix: -ane, -ene, and –yne.- if more than one double/triple bond, use prefix di-, tri- before suffix.

3) Number the carbons- start at end giving the lowest possible number for the double or triple bond OR- start at end giving the lowest possible number for the branches.

4) Find the prefix- name each branch as an alkyl group with position number.- if more than one branch, list in alphabetical order. - put the position number of any double or triple bonds after the position numbers and names of the branches, just before the root.

5) Put the name together: prefix + root + suffix.

How to Name Hydrocarbons

1) The main chain has ___ C. Root: _________2) Only ___________ bonds. Suffix:_________3) A _____________ group is attached to carbon

__________. Prefix: ____________5) Full name: ____________________________.

Name the following Compounds

1) Main ring (____________) has ___ Cs. Root: ______________.

2) Only _____________ bonds. Suffix: ______.3) And 4) A(n) ______________ group is

attached to carbon _____. Prefix: ________.5) Full name: __________________________.

1) Main chain has _____ C. Root: ___________.2) Contains one ________ bond. Suffix: ______.3) Two __________ groups on carbon___. One ____________ group on carbon ___.The = bond is at carbon _____.Prefix: ________________________________.5) Full name: __________________________.

Use hyphens (-) to separate words from numbers.

Use commas to separate numbers from each other.

Problem Tips

Draw a condensed structural diagram for 1-ethyl-2-methylhexane.

Drawing Hydrocarbons

Build one of the following hydrocarbons: 3-ethyl-2, 3, 4-trimethylnonane (SR, #2 d) 3-methyl-2,4,6-octatriene (PP #6, c) 4-ethyl-3-methylheptane (PP #6, b)

Large balls count as carbons.Small balls count as hydrogen.Carbons in the MAIN CHAIN do not require

hydrogens (will take up too much room).

Let’s Build Hydrocarbons!

Aromatic Compound: have a special form of sharing of electrons, such as benzene.

Benzene◦ Cyclic compound with three double bonds and three single bonds. ◦ Wacky molecule: electrons that form double bonds in benzene are

spread out and shared over the whole molecule.◦ Therefore, six identical bonds, each one half-way between single

and double.

Aromatic Compounds

Page 20.#1, 2, 3, 6.

Section Review

Functional Group: a group of bonded atoms in an organic compound that reacts in a characteristic way.

E.g.

1.3 – Single-Bonded Functional Groups

General Formula: the general formula for a family of organic compounds is R + Functional group.◦ R: any alkyl group.◦ E.g. R – OH

1) Compounds with the same functional group often have similar properties.

2) Compounds with the same functional group react chemically in very similar ways.

Functional Groups are Useful in classifying organic compounds for two reasons:

Common Functional Groups

Similar boiling points, melting points, and solubilities.

Due to intermolecular forces: forces of attraction and repulsion between particles.◦ Hydrogen Bonding: strong intermolecular

attraction between H atom of N-H, O-H, or F-H group on one molecule, and N, O, or F on another.

◦ Dipole-dipole interactions: polar molecules are attracted to eachother.

◦ Dispersion forces: occurs between all covalent molecules due to temporary dipoles.

Physical Properties of Families(same functional group)

1) What kinds of molecules are usually soluble in water? Why do you think this is?

2) Do polar or non-polar molecules usually have a higher boiling point? Why?

3) Substances A and B are both pure substances composed of polar molecules. Substance A also has the ability to hydrogen bond. Which one has a higher boiling point?

4) Polar molecules with a _____________ non-polar hydrocarbon part are less polar than polar molecules with a smaller non-polar hydrocarbon part.

5) Polar molecules with a large hydrocarbon part are less ____________ in water than polar molecules with a smaller hydrocarbon part.

7) Dispersion forces are stronger when _____________________________________

________________________________________________.

Intermolecular Forces and Physical Properties

See page 24 of your Textbook.Follow the procedure and answer the

questions in the thought lab.Report is due next class.

ThoughtLab

1) Alcohols2) Alkyl halides3) Ethers4) Amines

Compounds with Single-Bonded Functional Groups

1) Alcohols Contains the –OH functional group. Can be primary, secondary, or tertiary

depending on the position of the hydroxyl group.

Compounds with Single-Bonded Functional Groups

Naming an Alcohol:Read page 26 and go through SP.Do PP # 14, 15, 16.

Alkyl Halides One or more hydrogen atoms replaced with

halogen atoms: F, Cl, Br, or I. Functional group is R –X (x represents halogen).

Physical Properties of Alkyl Halides similar to alcohols.

Naming an Alkyl Halide:Read page 28, and do SP.Do PPs 18 – 21.

Ethers An organic compound that has two alkyl

groups joined by an oxygen atom. R – O – R Think of alcohols and ethers as derivatives

of the water molecules:

Ether examples:

How to Name an EtherRead pg. 29 and do SP on pg. 30PPs 22-24

Physical Properties of Ethers

Amines - NH2, - NHR, -NR2, where R is an alkyl group

attached to the nitrogen. General formula: R – NR’2 Thought of as derivatives of the ammonia

molecules, NH3. Classified as primary, secondary, or tertiary,

depending on how many alkyl groups attached to the nitrogen atom.

How to name an Amine:Read Page 31. Do SP on pg. 32PPs. 26-28

Finish all PPs not finished in class. SR 1, 2, 3, 5, 6, 7, 8.

Homework

C=O: Carbonyl Group Functional Groups with C=O bond

◦ Aldehydes◦ Ketones◦ Carboxylic Acids◦ Esters◦ Amides

1.4 – Functional Groups with C=O bond

An organic compound that has a double-bonded oxygen on the last carbon of a carbon chain.

General Formula: R-CHO

Aldehydes

To name an Aldehyde:1) Name the parent alkane. 2) Carbon atom of carbonyl group is C1.3) Replace –e at the end of the parent alkane

with –al. 4) Do not need to include position number for

carbonyl group.

Organic compound that has a double-bonded oxygen on any carbon within the carbon chain.

General Formula: RCOR’

Ketones

To name a ketone:1) Name the parent alkane. Main chain must

contain C=O group.2) One ketone group: replace –e with –one.

More than one: keep –e suffix and add –dione or –trione.

3) For carbon chains with more than four carbons, position number needed. Carbonyl group has lowest position number.

An organic compound with the following functional group:

-COOH General Formula: R-COOH.

Carboxylic Acids

Naming Carboxylic Acids1) Name parent alkane2) Replace –e with –oic acid.3) Carboxyl group is always position 1.

A derivative of a carboxylic acid.

General Formula: RCOOR’ Notice that the H of the carboxylic acid is

replaced by R’.

Esters

Naming an Ester1) Identify main part of ester containing C=O

group. Name this parent acid.2) Replace the –oic acid with –oate.3) Identify the part of the ester that is attached to

the oxygen atom. Name it as an alkyl group.4) Put the two names together.

Organic compound that has a carbon atom double-bonded to an oxygen atom and single-bonded to a nitrogen atom.

General formula: R-CO-NR2, where R can be H or an alkyl group.

Amides

Naming Amides1) Locate part of amide with C=O group. Name

this parent carboxylic acid. 2) Replace –oic acid with suffix –amide.3) Decide whether primary, secondary, or tertiary.

1) If two H on nitrogen atom, primary (no prefixes needed)

2) If one alkyl group attached to nitrogen, secondary. Name alkyl and give location letter N-

3) If two alkyl groups attached to nitrogen, tertiary. Place alkyls in alphabetical order and give location number N- or N,N- if alkyls identical.

Complete questions#1, 3, 4, 5, 6, 7.

Section Review (page 50)

Page 52 (You should go back through your notes/textbook)◦ Understand ALL Key terms◦ Knowledge/Understanding: #3-17◦ Inquiry: #18 (to hand in next class)◦ Communication: #19-22 (understand the idea

behind #23 & 24)

Chapter Review