Chapter 22 • Carbon and Hydrocarbons

• Diamond and Graphite video

Carbon

• Found in all living matter• 95% of all known compounds contain carbon• Carbon ranks 17th in abundance in the earths

crust• Has 4 valence electrons • Needs 4 more to become stable

Allotropes of Carbon

1. Diamond- colorless, crystalline solid- carbon atoms covalently bonded in a tetrahedral network-high melting point -used for cutting, drill bits, saw blades

2. Graphite-soft black form-carbon atoms covalently bonded in layers of

thin hexagonal plates-weak forces hold plates together so they slide

off easily-fair conductor of electricity

http://www.creative-chemistry.org.uk/molecules/structures.htm

3. Fullerenes-found in the mid 1980’s in black soot from organic decay and burning-dark colored solid made of spherically network carbon atoms-more stable and harder than diamond at high pressureC60 = Buckminsterfullerene molecule(Bucky ball)

Review:

Ionic Bond:-electrostatic force that holds two ions together-transfer of electronsCharacteristics:

-high melting pts.-soluble in water-well defined crystals-aqueous solutions-conduct

Covalent Bond:-shared pair(s) of electrons-elements in bond have nearly the same electronegativity

number-non-metal w/ non-metal-can be polar (un-equal) or non-polar (equal)Characteristics:

-low melting point, doesn’t conduct, brittle solids or gases or liquids

Organic Chemistry

• Study of carbon containing compounds excluding carbonates and oxides

• Originally “study of chemistry of life”

(Friedrich Wohler-found he could make the organic compound, urea, in the lab)

Organic vs. Inorganic

Organic1. Covalent bonds2. Long chained

molecules3. Decompose when

heated

Inorganic1. Ionic bonds or covalent

bonds2. Short chains3. Phase change or

vaporize when heated

4. Doesn’t dissolve readily in water

5. Reactions proceed at a very slow rate

4. Dissolves in water5. Reactions occur

immediately as reactants are brought together

6. Reactions are greatly affected by reaction conditions (like catalysts, heat, changes in pressure)

6. Reactions follow known patterns (single displacement, synthesis, etc)

Hydrocarbon

• Simplest organic compound composed of hydrogen and carbon

• Named with a set of prefixes and suffixes

Prefixes(stand for the # of carbons)

1 carbon -> meth-2 Carbons -> eth-3 -> prop-4 -> but-5 -> pent-6 -> hex-

7 carbons -> hept

8 -> oct-9 -> non-

10 -> dec-11 ->undecane-20 -> eicosane

Suffixes (tell type of bond)

- ane (single bond)- ene (double bond)- yne (triple bond)

Type of Formulas

-molecular formulas ( #’s and letters)C4 H10

- structural formula (shows bonding arrangement)

H H H H

H— C— C— C— C— HH H H H

- condensed structural formula

CH3—CH2—CH2—CH3

Aliphatic compounds

• Carbon atoms linked in chains

Cyclic compounds

• Carbon atoms linked in rings

Alkanes• All single bonds• Also known as saturated hydrocarbons• Filled with as many hydrogens as possible• Form saturated fats• Have (-ane) ending• Soluble in non-polar solvents• Boiling pt. Increases as # of carbons increase• General Formula: CnH 2n +2 (n= # of carbons)

C4 H?

C 4 H 10

Nomenclature (rules of naming)for Unbranched Alkanes

1. Count the number of carbons in the chain.2. Find prefix for that # of carbons- this is the

parent chain.3. Add (-ane) ending.

Ex. CH3—CH2—CH2—CH2—CH3

pentane

Branched Alkane Rules(adding branches, changes properties of compound)

1. Find the longest continuous chain of carbons- this is the parent chain (determine the name as you did before)

2. Number the carbons starting on the end of the parent chain closest to the branch.

3. The branch is a “Radical” molecule missing a Hydrogen atom

4. To name the radical- count carbons in radical, find prefix, add (-yl) ending

CH3—methylCH3 CH2—ethyl

5. Place the name of the radical (branch) b/4 the parent chain name.

6. Before the radical name, place the # of the carbon it is attached to.

7. If 2 or more “like” groups are in the chain, use prefixes (di-,tri-, tetra-) before the radical name with the #’s of the carbons they are attached to

Ex. 2,3,4 trimethyl octane

8. Name radicals alphabetically when they are differentEx. 3-ethyl-4-propyl nonane

Naming Cycloalkanes

- single bonded ring compound- Place word (cyclo-) in front of parent name

CH2CH2 CH2

CH2 CH2cyclopentane

Cyclohexane

cyclopropane

CH3

CH3

1,3 -dimethylcyclohexane

Isomers of Alkanes

• Have same molecular formula but different shape and structure

• Have same number of carbons and hydrogens• Isomers have different properties due to new

shapeEx. Butane (2 isomers), pentane (3 isomers),

hexane (5 isomers), decane (75 isomers)

PentaneCH3—CH2—CH2—CH2—CH3

CH3—CH—CH2—CH3 2-methyl butane

CH3 CH3

CH3—C—CH3 2,2 –dimethylpropane

CH3

Alkenes

• Have at least one double bond• Unsaturated hydrocarbon (forms unsat. Fats)• Use (-ene) ending• General formula CnH 2n

• More reactive than alkanes• Can’t rotate- due to double bond

Naming Alkenes

1. Find the parent chain- longest chain that contains the double bond.

2. Number the carbons- starting on end closest to double bond

3. Find prefix, add (-ene) ending, place the number of the carbon the double bond starts on before the parent name

CH3—CH=CH—CH2—CH2—CH3

Hexene

2-hexene

Branched alkene

1. Find parent chain, number carbons starting on end closest to the double bond but including the branch.

2. Name and number the parent chain3. Add the branch name and number before the

parent chain # and name

CH2=C—CH2—CH2—CH2—CH2—CH3

CH3

2-methyl-1-heptene

• More than one double bond use (-diene) or (-triene)

CH3—CH=CH—CH=CH—CH3

2,4- hexadiene

Geometric Isomers of Alkenes

• Isomer in which the arrangement of the carbons and branches are the same but the angle is different at the double bond

• Used for alkenes only• They differ in their geometry• Two types: cis and trans

cis- isomer

• Groups coming off the double bond are on the same side

H HC = C

CH3 CH3

cis-2-butene

trans- isomer

• Groups coming off the double bond are on opposite sides

H CH3

C = CCH3 H

trans-2-butene

Alkynes

• Unsaturated hydrocarbon• General formula Cn H 2n-2

• Very reactive• (-yne) ending

Naming Alkynes

- name like you name alkenes,except use (-yne) ending

CH3

CH3—C C—CH—CH3

4- methyl-2-pentyne

• If you have both a double and a triple bond, the double bond takes precedence in numbering

1-pentene-4-yne

CH2= CH - CH2 – C CH

Aromatics

• Constitutes a whole branch of chemistry• Rings with 6 carbons and 6 hydrogens and

every other bond is a double bond• Parent chain = benzene , C6H6

HC

H – C C – H H – C C – H

C H

Naming aromatics

1. Parent chain is benzene2. Number so a branch is on the number 1

carbon and then number the other branches so they are on the lowest number possible

CH3 CH3

1,2 -dimethylbenzene

Benzene Facts

• Not as reactive as alkenes• Very stable• 1000’s of compounds contain benzene• Benzene is a carcinogen• Can fuse rings• Naphthalene

• A benzene ring can be made a radical by removing a hydrogen

• Call it a phenyl- radical

CH3—CH—CH2—CH2—CH3

2-phenyl pentane

Saturated & Unsaturated Fats

• Fall under a category called lipids• Not soluble in water• Contains Carbons, Hydrogens, oxygens

Saturated Fats

• Made from saturated fatty acids O

CH3—CH2—CH2—(CH2)12—CH2 – CH2 – C – OH

Palmitic acid• All single bond, very long chain

• Most come from animal sources• Solids at room temperature• Clogs arteries, cause heart attacks, because all

single bonds –the body can’t break down

Unsaturated Fats

• Made from unsaturated fatty acids

OCH3—(CH2)7—CH=CH—(CH2)6 – C – OH

Oleic acid

• Have at least one double bond• Liquid at room temperature• Most come from vegetable sources• Body can break down easier because of the

double bond (healthier)• Polyunsaturated fat= more than one double

bond

Tests for Saturation

Bromine Water Test:-add 1 ml of Bromine water to fat, stopper, mix-Remains yellow= saturated- Turns colorless = unsaturated

Potassium Permanganate Test (KMnO4)

-add KMnO4 with NaOH to fat, heat, observe

-Remains purple = saturated-Turns green = unsaturated

Degree of Saturation

• Use iodine solution,• red-brown color disappears when it is added to

an unsaturated fat• Red-brown color remains in a more saturated fat• One can time the fading, faster –more

unsaturated

Distillation

• Water and liquids often contain impurities, of which are objectionable and can be removed through a distillation process

Distillation = process in which a liquid is separated from a mixture by heating it up to its boiling point and recondensing it back into a liquid distillate (separation by boiling point)

The Process:

• Heat the solution so the substance with the lowest boiling point evaporates and then the evaporated gas is cooled in a condenser column and collected in a separate container

Uses of distillation

• To purify• To separate out the mixture into different

fractions to be tested• To prepare drinking water from salt water• To distill alcohol• To refine petroleum (using a method called

fractionation in a fractionating tower)

Substitutions

• Occurs when one exchanges a carbon or hydrogen for other elements or molecules

• Substitutions increase the reactivity• The non-hydrocarbon part of the molecule is

called a functional group• Different families: halogens, alcohols, ethers,

acids, ketones, aldehydes, esters, amines,amides

Halogen Derivatives

• Substitute a hydrogen with a halogen• Group 17- Cl, Br, F, I• Have prefixes of chloro, fluro, bromo, and iodo

HH - C – Br H bromomethane

Also possible to have more than one substitutionEx. Trichloromethane CH- Cl3

(chloroform- solvent, anesthetic)

Naming:• Number as before, find parent chain name• Substituted halogens are treated like branches

(placing them on lowest number possible)• If there is a double bond-it takes numbering

precedence• Aromatics- assign numbers so the halogen is on

smallest

2-bromo-2-methylpropane

1-iodo-2,2-dimethylpropane

1,2-dibromobenzene

Br Br

Alcohol

• Contains a functional group called a hydroxyl group (-OH)

• This is not a hydroxide because it is covalently bonded

• General formula: R-OH (R= parent chain)• They are neither acidic or basic

Ex. Methanol CH3-OH -plastics and fibersethanol CH3-CH2-OH – solvent2-propanol CH3-CH-CH3 –rubbing alcohol

OH-less than 4 carbons- soluble in water

• Can have more than one hydroxyl group

Ex. Ethylene glycol (antifreeze)- 1,2-ethandiol

• When attached to a benzene ring it becomes a phenol (also becomes slightly acidic)

• Phenol- used in drugs, plastics, fibers

Naming Alcohols

• Drop the (-e) ending in parent name• Add the ending of (-ol)• Number it so the hydroxyl group is on the lowest

possible number• If it has more than one hydroxyl use: diol, triol,

tetrol• Double bond takes precedence (2-hexen-3-ol)

3-methyl-1-butanol

Ex.

1,2,3 –propantriol (glycerol or glycerin- viscous, sweet liquid used in making candy and for moisterizing hand lotion)

Properties of Alcohols

Ethyl alcohol-boiling point 78.5 C-used in fermentation –production of ethanol from sugars by the action of yeast or bacteria

C6H12O6 2 CH3CH2OH + 2 CO2

(glucose) yeast (ethanol) (carbon dioxide)

- Ethanol is the intoxicating substance in alcohol, also damages the liver

- Proof numbers are twice the alcohol content (90 proof = 45% alcohol)

- Ethanol has industrial uses so it is denatured with methanol to make it toxic (government demands it)

Methyl alcohol -methanol or wood alcohol-used to distill wood to make this b/4 1925-this is the toxic substance added to ethanol

10 ml – causes permanent blindness30 ml = death

Ethers

(don’t need to name, just recognize)-general formula -> R-O-R΄- R and R΄ are two diff. parent chains- naming: just name the 2 carbon parent groups with the

word ether after them (ex. Ethyl methyl ether)- More soluble than hydrocarbons, less than alcohol- Lower boiling point than alcohols, higher than

hydrocarbons

Ex. Diethyl ether **Need to Know**

CH3- CH2 – O – CH2- CH3

-used for anesthetic-in 1842 Crawford Long, American Doctor,

replaced this because of its flammability and nausea side effects

Aldehydes

• General formula O R- C- H

-the end carbon has a double bonded oxygen and an H on an end of it

- C=O is called a carbonyl group- Ending is (-al)- Get aldehydes by the conversion of primary alcohols

Ex. Methanal or formaldehyde **Need to know**O

H – C – H-use to make plastics and adhesives-only aldehyde w/ industrial significance-used as a preservative for biological specimensEx. Also – benzaldehyde (almond, ring, stink-o)

Ketones

• General formula= OR – C - R΄

-also made from alcohol (secondary alcohol)- ending is (-one)- Because of the carbonyl group, aldehydes and

ketones have similar properties

Ex. Propanone or acetone **need to know**

OCH3- C – CH3

-made from 2-propanol-solvent for resins, plastics, varnishes and as a

polish remover

Carboxylic acid or Organic Acids

• General formula: O R - C- OH

- has a carboxyl group O - C- OH

-name-> drop (-e) in parent chain, add (-oic acid)-these are weak acids, that have a pungent-icky-

odor

Ex. Acetic acid or ethanoic acid or vinegar**need to know**

O CH3 – C – OH

-note: common names tend to be used more than the IUPAC names

Ester

• Derivatives of a carboxylic acid and alcohol• General formula:

O R- C – O - R΄

Uses: pleasant fragrances, fruits, flowers, perfume, smelly stickers

Esterification Reaction

• Formation of an ester

Alcohol + organic acid -> ester + water O O

R-OH + R’-C –OH - > R’-C-O-R + H2O

(take the H from the alcohol and OH from the acid)

OCH3-C-OH + CH3CH2 –OH ->

O CH3-C-O-CH2-CH3 + H2O

Ester stoichiometry

Acetic acid + ethanol <-> ethyl acetate + water1.48 g 1.63g

1. Find limiting reactant by converting both reactants to moles

Molar mass- acetic acid = 60.0 g/molMolar mass – ethanol = 46.0 g/mol

1.48 g acetic 1 mole 60.0g acetic = .0247 mole

1.63 g ethanol 1 mole46.0 g ethanol = .0354 mole

- the one w/ smallest # moles is limiting

2. Set up stoichiometry equation w/ ester as unknown, limiting reactant as knownMolar mass = ethyl acetate = 88.0 g/mol

1.48 g acetic 1 mole 1 mole ester 88.0 g ester 60.0 g acetic 1 mole acetic 1 mole

ester

2.17 g ethyl acetate

Amines

• A nitrogen is bonded to the carbon chainGeneral formula

H- N- R or R-N-R’ H H

Ex. Diethyl amine *knowCH3- CH2 – N – CH2 – CH3

H (amino acid building block)

Amide

• Has a carbonyl group and amineGeneral formula

O

R- C – NH2

Ex. Urea O

H2N-C-NH2 xxxneed to know

-used in fertilizer and plastic production

Song

The End

Test

• 14 multiple choice- definitions, common hydrocarbons, rules for naming, etc

• Isomer question• 4- going from drawing to name• 4 – going from name to

drawing• 8 matching –functional groups• 1 ester Stoichiometry

• 2 ester equations• Fermentation reaction• Essays-

– cis/trans– Saturated vs unsat and the tests– Distillation- how and examples– Differences between organic and

inorganic (use chart in notes)