Chapter 20 Organic Chemistry Objective: Students will understand how to name the alkanes.

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Chapter 20Chapter 20

Organic Chemistry

Objective: Students will understand how to name the alkanes.

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What is ORGANIC Chemistry?What is ORGANIC Chemistry?

The study of carbon-containing compounds (typically chains of carbon atoms) and their properties.

Carbon atoms can link to other carbon atoms indefinitely.

HYDROCARBONSHYDROCARBONS

Compounds containing carbon and hydrogen only. There are several classes.

The first is ALKANES.

ALKANESALKANESAlkanes are the simplest of the hydrocarbons.

They only contain carbon-hydrogen bonds and carbon-carbon single bonds. The first ten are:

Their formulas are alwaysCxH2x+2 C6H14 is an example

TEN ALKANESTEN ALKANES

The names of the Alkanes always end in -ane

Figure 20.2: The Lewis structure of ethane.Figure 20.2: The Lewis structure of ethane.

Name the CompoundName the Compound

What is a branched-chained alkane?What is a branched-chained alkane?

Naming Branched Naming Branched Chained AlkanesChained Alkanes

of your text

and 642 of your text

of your text

Name the CompoundName the Compound

Name The CompoundName The Compound

Calculating the molar-mass Calculating the molar-mass Branched Chained AlkanesBranched Chained Alkanes

Calculating the molar mass of alkanes is easy.1. Determine the total number of carbons and

times that number by 12.2. Then determine the number of hydrogens.

( 2x the carbons + 2 more)3. Add the two together.

Calculating the molar-mass Calculating the molar-mass Branched Chained AlkanesBranched Chained Alkanes

Example:Find the molar-mass of 2,3-dimethylpentane.

There are 5 carbons in pentane and 1 carbon in each methyl so a total of 7.

That means there are a total of 16 hydrogen atoms.

12 x 7 + 16 = 84 + 16 = 100

Isotopes of ButaneIsotopes of Butane

Stop here for the 1Stop here for the 1stst Assignment Assignment

Start here for the 2Start here for the 2ndnd Assignment Assignment

For this day we will draw and name the isomers of Heptane.Then we will learn how to identify and name ALKENES and ALKYNESThere is a clicker quiz named “ALKENES AND ALKYNES”

ISOMERSISOMERS

In class assignmentDraw and name the nine isomers of Heptane C7H16

What is a BLEVE?What is a BLEVE?

An acronym for “boiling liquid escaping vapor explosion

VIDEO #1Video #2 The jet sound is a bleve!Video #3 Notice how the fire keeps its

shape? That’s because the fuel must mix with oxygen in just the right ratio

A closer look at this fireA closer look at this fire

PropanePropane

Properties of ALKANESProperties of ALKANES

AlkenesAlkenes

Alkenes are hydrocarbons with double bonds. They are unsaturated and often referred to as “olefins”

The name of alkenes end in –ene.Ethene, Propene Butene Pentene

Cis and TransCis and Trans

Double bonds on the carbons prevents the carbon atoms from rotating around each other.

Naming AlkenesNaming Alkenes

When naming alkenes give the lowest number to the double bond.

Then name the side chains

Name the compoundName the compound

Trans-3-heptene4-methyl-cis-2 pentene

ButadieneButadiene

Butadiene is butane with two double bondsC=C-C=C 2,3-butadiene

Cyclo-hydrocarbons Cyclo-hydrocarbons

Hydrocarbons that are in a ring are called cyclo-hydrocarbons

AlkynesAlkynes

Alkynes are hydrocarbons that have a triple bond. They are very reactive.

Video controlled explosion of ethyne.

Naming Aromatic Compounds Naming Aromatic Compounds BENZENEBENZENE

Objective: Students will understand the historical significance of Benzene, its structure and how to name compounds containing benzene.

Figure 20.8: Two Lewis structures for the benzene ring.Figure 20.8: Two Lewis structures for the benzene ring.

1.3.5-Cyclohexatriene.1.3.5-Cyclohexatriene.

Early usesEarly uses

In the 19th and early-20th centuries, benzene was used as an after-shave lotion because of its pleasant smell. Prior to the 1920s, benzene was used as an industrial solvent. To decaffeinate coffee

Later benzene was used to improve the anti-knock in gasoline.

Benzene is an AROMATIC CompoundBenzene is an AROMATIC Compound

The term 'aromatic' was assigned before the physical mechanism determining aromaticity was discovered, and was derived from the fact that many of the compounds have a sweet scent.

Benzene Benzene

Tylenol and AdvilTylenol and Advil

TolueneTolueneWhen a methyl group is attached to a benzene

ring, the whole structure is referred to as toluene.

This is the #1 Carbon

Naming Compounds Containing TolueneNaming Compounds Containing Toluene

toluene

2 chloro-toluene

2,3 dichloro-toluene

2,4,6-trinitrotoluene2,4,6-trinitrotoluene

Phenyl GroupsPhenyl Groups

Petroleum Petroleum This is a mixture of many compounds taken

out of the earth and separated into purer compounds by means of a distillation tower.

Figure 20.7: Benzene CFigure 20.7: Benzene C66HH66..

Figure 20.8: Shorthand notation for benzene rings.Figure 20.8: Shorthand notation for benzene rings.

Figure 20.10: Figure 20.10: Names of Names of

some some common common

monosubstitutmonosubstituted benzenes.ed benzenes.

Figure 20.5: Energy sources used in the United States.Figure 20.5: Energy sources used in the United States.

Figure 20.6: Ball-and-stick model of ethylene.Figure 20.6: Ball-and-stick model of ethylene.

Figure 20.13: Figure 20.13: Some carboxylic Some carboxylic

acids.acids.

Table 20.5Table 20.5

What is an Alcohol? What is an Alcohol?

Alcohols: Contain the hydroxyl functional group, –OH which replaces an –H in the alkane.

How to name AlcoholsHow to name Alcohols

Alcohols are named by replacing the “-e” ending of the alkane with a “-ol” ending.

• methane, CH4, gives methanol, CH3OH

• ethane, C2H6, gives ethanol, C2H5OH

• Propane, , gives 2-propanol,

Organic AcidsOrganic Acids

Organic Acids Contain the carboxyl Functional Group, –COOH

What is a Keytone?What is a Keytone?

Ketones: Have the carbonyl functional group bonded between two hydrocarbon units.

Naming KeytonesNaming Keytones

Ketones are named by replacing the -e ending of the alkane with the -one ending and prefixing the name with the number of the carbonyl carbon

Aldehydes Aldehydes

Figure 20.9: The bonding in the benzene ring is a combination of different Lewis structures.Figure 20.9: The bonding in the benzene ring is a combination of different Lewis structures.

Chapter 20 Organic Chemistry Objective: Students will understand how to name the alkanes.

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