Organic “Carbon” Chemistry

Chapter 13-14Science 10CT03D01Resource: Brown, Ford, Ryan, IB Chem

Organic “Carbon” Chemistry

Chemistry for you, Lawrie RyanChapter 13 Pages 159-177 Hydrocarbons, Fossil Fuels, Distillation

of Crude Oil, Cracking, Plastics, Polymers

Chapter 14 Pages 178-185 Alcohols, Isomers, Ethanol, Alcohol

Reactions, Carboxylic Acids

13.1 - HydrocarbonsA hydrocarbon is a compound containing only hydrogen and carbonCrude Oil, which is very important to the survival Venezuela is a mixture of many hydrocarbons Not only vital for fuels but also the starting

materials for plastics and other polymers

13.1 - AlkanesThe most common hydrocarbon found in crude oil is an alkaneAn alkane contains a ‘backbone’ of single-bonded carbon atoms and is saturated with hydrogen atomsNatural gas, methane, CH4, is the shortest alkane

AlkaneMethane, CH4

Ethane, C2H6

Propane, C3H8

Butane, C4H10

Pentane, C5H12

Hexane, C6H14

Heptane, ______Octane, _______

13.2 – Fossil FuelsMost common fuels are fossil fuels Coal, crude oil, natural gas, etc

Coal, although it’s not a hydrocarbon, does contain carbon and hydrogen, as well as oxygen in some of it’s molecules From organic material (like trees) that died and were

buried below swampsCrude oil, hydrocarbons Formed from tiny animals and plants which lived in

the seaTakes millions of years to form fossil fuels

In reality the energy comes from the sun to produce fossil fuels, but it simply takes so long to produce

13.2 – Finding OilCrude oil today was made from mainly plankton that died about 150 million years ago. Their bodies did not decay normally due to lack of oxygen and with high pressures and temperatures, formed oil and natural gas. We can find oil by surveying the land and it’s topography Look for dome shaped layers (cap rock or anti-cline) Seismic survey

13.3 – Distilling Crude OilWhen crude oil reaches the refinery it’s a thick, black, and smelly liquid This liquid contains long hydrocarbon chains

At the refinery the long chains can be sorted out into groups of useful substances called fractions We can separate these substances by fractional

distillation which separates substances based on their boiling pointFraction Length Color Thicknes

sReactivity

Low BP (up to 80C)

Short Clear Runny Easily lit (flammable, clean flame)

Medium BP (80-150C)

Medium

Yellow Thicker Harder to light, some smoke

High BP (above 150C)

Long Dark orange

Thick Difficult to light, smoky flame

13.4 – Fractional Distillation in Industry

Fraction Length of Carbon Chain

Petroleum gas C1-C4

Petrol C4-C12

Kerosine C11-C15

Diesel C15-C19

Lubricating Oil C20-C30

Fuel Oil C30-C40

Bitumen C50 +

13.5 - CrackingAfter distillation of crude oil companies are still left with long hydrocarbons and the need is for shorter chains like petrolThe solution is cracking meaning big molecules are broken down by heating them over a catalyst This is competed inside a cracker

13.6 - PlasticsWhen oil companies crack large molecules into smaller ones, ethene is made Ethene is just like ethane, but with a double bond

making it unsaturated

This ethene molecule is the starting material for plastics. When the double bond is broken, new bonds can form between several molecules forming polymers Lots of small, reactive molecules called monomers join

together to make a polymer

vs

ethene

13.7 – Ethene and the Alkenes

Alkenes, which are also hydrocarbons, are very similar to alkanes, but are not saturated. They have at least one double bond and less hydrogen atoms which makes them unsaturated. Their names end in –ene instead of –ane Contain double bonds Very reactive Building block for polymers Also react with

Br, Cl, I, F water Strong acids Water and sulfuric adid

Alkane AlkeneMethane, CH4

Ethane, C2H6 Ethene, C2H4

Propane, C3H8 Propene, C3H6

Butane, C4H10 Butene, C4H8

Pentane, C5H12 Pentene, C5H10

Hexane, C6H14 Hexene, C6H12

Heptane, ______ Heptene, ______Octane, _______ Octene, _______

13.8 - Polymerization

There are two types of reactions that make polymers Addition – where at least two things simply

join together Condensation – where water is given off in

the process of joining molecules. Also known as dehydration synthesis

13.8 – Addition Polymerization

Addition Reactions Monomers have at least one double bond The polymer is the only material formed in the

reaction Easiest example is ethene used to make

poly(ethene) n C2H4 -[-C2H4-]-n Where n = large number

The double bonds open up to form single bonds to the adjacent monomer

R can be just about anything

13.9 – Condensation PolymerizationNylon is an example of a polymer formed through condensation Fumes are given off as the different monomers

react together. These small molecules given off could be H2O, HCl, etc. It depends on the ends of the monomers.

The monomers have reactive parts at both ends and join end-to-end to make long chain polymers

+ H2O

13.10 – Properties of Plastics

Many materials are made out of plastics PVC piping, bags, surfaces, protective films,

bottles, etcPlastics often have advantages over the use of metal compounds and cost much lessWhen we run out of oil we will also run out of access to cheap plastics This is why recycling our plastics is so important!!

Chapter 14 – Organic Molecules

Nomenclature! How do we name organic

compounds? Alkane vs alkene Saturated vs unsaturated Functional groups Length of chain

Types of Organic MoleculesSaturated Unsaturated

•Compounds which contain only single bonds•For example: alkanes

•Compounds which contain double or triple bonds•For example: alkenes, arenes

Aliphatics Arenes

•Compounds which do not contain a benzene ring; may be saturated or unsaturated•For example: alkanes, alkenes

•Compounds which contain a benzene ring; they are all unsaturated compounds•For example: benzene, phenol

14.1 – Types of Organics

Differ by a CH2

Can be represented by the same general formulaShow gradation in physical propertiesHave similar chemical properties

14.2 - Members of Homologous Series

14.2 - Members of Homologous Series…

… differ by a –CH2 group

14.2 - Members of Homologous Series…

… can be represented by the same general formula

Formula NameCH4OH Methan-1-olC2H5OH Ethan-1-olC3H7OH Propan-1-olC4H9OH Butan-1-olC5H11OH Pentan-1-olC6H13OH Hexan-1-olC7H15OH Heptan-1-olC8H17OH Octan-1-ol

14.2 - Members of Homologous Series…

… show gradation in physical propertiesAlkane Boiling Point

Methane, CH4 -164Ethane, C2H6 -89Propane, C3H8 -42Butane, C4H10 -0.5Pentane, C5H12 36Hexane, C6H14 69Heptane, C7H16 98Octane, C8H18 125

Since the series differ by one –CH2 they have successively longer carbon chains

Results in gradual trend of phy. Props Not always a linear growth Density and viscosity are other examples

14.2 - Members of Homologous Series…

… show similar chemical propertiesAs the have the same functional group

Ex.1 – the alcohols have a functional –OH group, which can be oxidized to form organic acidsEx. 2 – the –COOH functional group, present in the homologous series of the carboxylic acids, is responsible for the acidic properties of these compounds

14.3 – Organic FormulasEmperical formula Simplest whole number ratio Ethane CH3

Molecular formula Actual number of atoms Ethane C2H6

Structural Formula Full, condensed, steriochemical

14.3 - Emperical FormulaThe simplest whole number ratio of the atoms it contains. For example, the emperical formula of ethane, C2H6, is CH3. This formula can be derived from percentage composition data obtained from combustion analysis. It is, however, of rather limited use on it’s own, as it does not tell us the actual number of atoms in the molecule.

14.3 - Molecular FormulaActual number of atoms of each element present. For example, the molecular formula of ethane is C2H6. It is therefore a multiple of the emperical formula, and so can be deduced if we know both the emperical formula and the relative molecular mass Mr.

14.3 - Full Structural FormulaGraphic formula or displayed formula – shows every bonded atom. Usually 90o and 180o angles are used to show the bonds because this is the clearest 2-D representation, although it is not the true geometry of the molecule

14.3 - Condensed Structural Formula

Often omits bonds where they can be assumed, and groups atoms together. It contains the minimum information needed to describe the molecule non-ambiguously – in other words there is only one possible structure that could be described by its formula.

14.4 – IUPAC Nomenclature

Nomenclature for Organic Compounds: the IUPAC system International Union of Pure and Applied

Chemistry Rule 1: Identify the longest straight

chain of carbons Rule 2: Identify the functional group Rule 3: Identify the side chains or

substituent groups

14.4 - IUPAC Rule 1: Longest Chain

# C atoms in longest

Stem in IUPAC name

Example

1 meth- CH4 methane2 eth- C2H6 ethane3 prop- C3H8 propane4 but- C4H10 octane5 pent- C5H12 pentane6 hex- C6H14 hexaneNote: ‘straight chain’ does not mean just 180o angles or unbranched

chains of carbon atoms. Be careful, do not be confused by the way the molecule may appear on paper because of free rotation around the carbon-carbon single bonds. Example, all three below are the same….

15.4 - IUPAC Rule 2: Functional Group

The functional group is described by a specific ending (or suffix) to the name, that replaces the –ane ending of the name of the parent alkane. The suffixes used for some common functional groups are in the slides to follow. Those marked * will have slides with further information.

14.4 - Functional GroupsHomologous Series

Functional Group

Suffix in IUPAC name

Example of compound

Alkane -ane C3H8 propane

Alkene -ene CH3CH=CH2 propene

Alcohol -anol C3H7OH propanolHalogen -Cl -F -Br chloro, Fluoro,

bromochloromethane

14.4 - IUPAC Rule 3: Side Chains

Side Chain Prefix in IUPAC

Example of Compound

-CH3 methly- CH3CH(CH3)CH32-methylpropane

-C2H5 ethly- CH(C2H5)33-ethlypentane

-C3H7 proply- CH(C3H7)34-propylheptane

-F , -Cl , -Br , -I

fluoro- , chloro- , bromo- , iodo-

CCl4Tetrachloromethane

-NH2 amino- CH2(NH2)COOH2-aminoethanoic acid

14.5 - Structural IsomersDifferent arrangements of the same atoms make different moleculesMolecular formula shows the atoms that are present in a molecule, but gives no information on how they are arranged. Consider, for example, C4H10

Each isomer is a distinct compound, having unique physical and chemical properties.

14.5 - Structural Isomers of Alkenes

14.6 - Alkanes as FuelsRelease significant amounts of energy when they burn, highly exothermic, because large amount of energy released when forming.. Double bonds of CO2 Bonds in H2O

C3H8 + 5O2 3CO2 + 4H2O ΔH = -2200 kJ/mol

However, when O2 is limited…..2C3H8 + 7O2 6CO + 8H2O

when O2 is extremely limited…..C3H8 + 2O2 3C + 4H2O

These are examples of the incomplete combustion of fossilfuels which makes them an environmental concern