Compounds of CarbonCompounds of Carbon

Chapter 9Chapter 9

CarbonCarbon

Over seven million compounds containing Over seven million compounds containing carbon are known. carbon are known.

Think of all the things you know that contain Think of all the things you know that contain carbon, what are they??carbon, what are they??

Carbons electronic structure is 1sCarbons electronic structure is 1s222s2s222p2p22

It is found in period 2, group 14 of the periodic It is found in period 2, group 14 of the periodic tabletable

It has four outer shell electrons and it can form It has four outer shell electrons and it can form covalent bonds with these electrons.covalent bonds with these electrons.

Bonding in carbon compoundsBonding in carbon compounds

Carbon forms strong covalent bonds with Carbon forms strong covalent bonds with hydrogen atoms, and nearly all organic hydrogen atoms, and nearly all organic molecules contain hydrogen bonded to carbon. molecules contain hydrogen bonded to carbon.

Carbon also forms strong covalent bonds with Carbon also forms strong covalent bonds with other carbon atoms, forming long chains and other carbon atoms, forming long chains and rings.rings.

It can form single, double or triple bonds.It can form single, double or triple bonds. It can also form covalent bonds with other It can also form covalent bonds with other

atoms.atoms.

Bonding in carbon compoundsBonding in carbon compounds

When four single bonds are formed around a When four single bonds are formed around a carbon atom, the pairs of electrons in each carbon atom, the pairs of electrons in each bond act as a charge cloud.bond act as a charge cloud.

These charge clouds repel each other so that These charge clouds repel each other so that they spread out as far as possible. they spread out as far as possible.

This arrangement is called a tetrahedral This arrangement is called a tetrahedral distribution. distribution.

Homologous seriesHomologous series

Homologous series just means a family of Homologous series just means a family of certain molecules.certain molecules.

Alkanes and alkenes are both forms of these Alkanes and alkenes are both forms of these homologous series.homologous series.

AlkanesAlkanes

Saturated hydrocarbons as every Saturated hydrocarbons as every carbon has a hydrogen attached.carbon has a hydrogen attached.

Molecular formula CMolecular formula CnnHH2n+22n+2

The molecules can be written by a The molecules can be written by a structural formula, as shown right or structural formula, as shown right or a semi-structural formula.a semi-structural formula.

CHCH33CHCH22CHCH22CHCH33 or CH or CH33(CH(CH22)CH)CH33

Cyclic MoleculesCyclic Molecules A chain or carbon atoms can also be bent round to form a ring. A chain or carbon atoms can also be bent round to form a ring.

Benzene is a bit different, three of the four outer shell Benzene is a bit different, three of the four outer shell electrons form normal covalent bonds but the fourth electron electrons form normal covalent bonds but the fourth electron is shared (delocalised) around the six-membered ring.is shared (delocalised) around the six-membered ring.

Compounds like this are called arenes.Compounds like this are called arenes.

OR

IsomersIsomers Isomers are the same Isomers are the same

molecular formula but molecular formula but different structural formula. different structural formula.

Structural isomers can have Structural isomers can have different chemical and different chemical and physical properties.physical properties.

Butane and bigger all have Butane and bigger all have structural isomers.structural isomers.

There are 75 structural isomers There are 75 structural isomers for decane.for decane.

What are the three for pentane, What are the three for pentane, what are they??what are they??

Naming alkanesNaming alkanes Remember from last year. Alkanes are named in a Remember from last year. Alkanes are named in a

certain way. certain way. The first part of the name indicates the number of The first part of the name indicates the number of

carbon atoms and the last part ends in ane. carbon atoms and the last part ends in ane. The fragment of alkane that forms a side chain is The fragment of alkane that forms a side chain is

called an alkyl group.called an alkyl group.

Naming AlkanesNaming Alkanes

Systematic names for alkanes are made up Systematic names for alkanes are made up of:of:

The name of the longest alkane hydrocarbon The name of the longest alkane hydrocarbon chainchain

The name and number of any alkyl side chainThe name and number of any alkyl side chain The position of the side chain on the main carbon The position of the side chain on the main carbon

chain.chain. The longest unbranched carbon chain is The longest unbranched carbon chain is

chosen as the stem for naming the moleculechosen as the stem for naming the molecule

Time to test youTime to test you Name theseName these

AlkenesAlkenes

Hydrocarbons with double covalent bonds are called Hydrocarbons with double covalent bonds are called alkenes. alkenes.

Their names end in ene.Their names end in ene. Alkenes are unsaturated hydrocarbons as the double Alkenes are unsaturated hydrocarbons as the double

bonds prevent the carbons from bonding with the bonds prevent the carbons from bonding with the maximum number of hydrogens.maximum number of hydrogens.

The formula is CThe formula is CnnHH2n2n.. For butene and higher the double bond can be located For butene and higher the double bond can be located

in various positions in the carbon chainin various positions in the carbon chain

Naming alkenesNaming alkenes

Look at the longest carbon chain that contains Look at the longest carbon chain that contains the double bond.the double bond.

The position of the double bond is indicated by The position of the double bond is indicated by the number of the first carbon atom involved the number of the first carbon atom involved in the double bond.in the double bond.

The numbering should start at the end nearest The numbering should start at the end nearest to the double bond. to the double bond.

The rules for naming any side chains are the The rules for naming any side chains are the same for alkanes.same for alkanes.

Naming AlkenesNaming Alkenes

Over to youOver to you

Page 137Page 137 Question 2, 3 and 6Question 2, 3 and 6

Functional GroupsFunctional Groups

So far we have looked only at compounds So far we have looked only at compounds containing hydrogen and carbon.containing hydrogen and carbon.

Carbon can also form bonds with other atoms Carbon can also form bonds with other atoms or groups of atoms. These are called functional or groups of atoms. These are called functional groups.groups.

A functional group is an atom or a group of A functional group is an atom or a group of atoms that gives a characteristic set of atoms that gives a characteristic set of chemical properties to a molecule containing chemical properties to a molecule containing that group.that group.

Functional groupsFunctional groups

Many compounds can be produced Many compounds can be produced by substituting a hydrogen atom in by substituting a hydrogen atom in an alkane with different functional an alkane with different functional groups.groups.

-C-C- and –C-H bonds are strong -C-C- and –C-H bonds are strong and relatively unreactive, but when a and relatively unreactive, but when a functional group is added it can functional group is added it can completely change the properties of completely change the properties of the carbon chain.the carbon chain.

ChloroalkanesChloroalkanes

It is possible to replace a hydrogen atom in an alkane It is possible to replace a hydrogen atom in an alkane with chlorine atoms to form a chloroalkane. with chlorine atoms to form a chloroalkane.

The systematic name for a chloroalkane starts with The systematic name for a chloroalkane starts with chloro followed by the name of the alkane from chloro followed by the name of the alkane from which it is derived.which it is derived.

For compounds with more than 3 carbons it is For compounds with more than 3 carbons it is possible to place a chlorine atom at the end or in the possible to place a chlorine atom at the end or in the middle of the chain so we use numbers to indicate the middle of the chain so we use numbers to indicate the position of the chlorine. position of the chlorine.

Lets look at page 138.Lets look at page 138.

AlkanolsAlkanols

Alkanols are more commonly called alcohols. Alkanols are more commonly called alcohols. They have the functional group R-OHThey have the functional group R-OH The hydroxy group has been substituted for one The hydroxy group has been substituted for one

hydrogen in an alkane.hydrogen in an alkane. Hydrogen bonds involving the polar head of the –OH Hydrogen bonds involving the polar head of the –OH

group influence the properties of alcohols. group influence the properties of alcohols. Compared to alkanes, alcohols are more soluble in Compared to alkanes, alcohols are more soluble in

water and have higher boiling points.water and have higher boiling points.

AlcoholsAlcohols

Alcohols are named by dopping the ‘e’ at the end of Alcohols are named by dopping the ‘e’ at the end of the alkane and replacing it with an ‘ol.’the alkane and replacing it with an ‘ol.’

Ethane becomes ethanol.Ethane becomes ethanol. For propanol and higher it is important to number the For propanol and higher it is important to number the

carbon chain and give the number where the alcohol carbon chain and give the number where the alcohol group is located. group is located.

Draw Propan-1-ol and propan-2-ol.Draw Propan-1-ol and propan-2-ol. Can you name this structure?Can you name this structure?

Carboxylic acidsCarboxylic acids

Contain the carboxy functional group Contain the carboxy functional group R-COOHR-COOH

Bonds with the COOH functional group are Bonds with the COOH functional group are polarised, resulting in the formation of polarised, resulting in the formation of hydrogen bonds between molecules. hydrogen bonds between molecules.

Low molecular carboxylic acids are soluble in Low molecular carboxylic acids are soluble in water.water.

Naming Carboxylic acidsNaming Carboxylic acids

The stem of the systematic name of carboxylic The stem of the systematic name of carboxylic acids is determined from the number of carbon acids is determined from the number of carbon atoms in the longest chain that contains the atoms in the longest chain that contains the COOH functional group.COOH functional group.

Add “oic acid” at the end of the name.Add “oic acid” at the end of the name. Ethane becomes ethanoic acidEthane becomes ethanoic acid

AminesAmines

Organic compounds that contain the –NHOrganic compounds that contain the –NH22 functional functional group are called aminesgroup are called amines

Around the nitrogen atom there are three pairs on Around the nitrogen atom there are three pairs on electrons involved in bond formation and one lone electrons involved in bond formation and one lone pair of electrons.pair of electrons.

The bonds around the nitrogen atom are polar due to The bonds around the nitrogen atom are polar due to the high electronegativity of nitrogen.the high electronegativity of nitrogen.

The smaller amines are very soluble in water but The smaller amines are very soluble in water but solubility decreases as the size of the alkyl group gets solubility decreases as the size of the alkyl group gets larger.larger.

AminesAmines

The amines are named by adding amino to the The amines are named by adding amino to the name of the alkanename of the alkane

Amino acids are basic building blocks for Amino acids are basic building blocks for proteins. They contain the amine and the proteins. They contain the amine and the carboxylic acid functional groups. carboxylic acid functional groups.

Name these structures???Name these structures???

Your TurnYour Turn

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