Unit 10: Organic Chemistry What is a hydrocarbon?

What is an organic compound? Organic Compounds are a special category of covalent compounds. This is because C can make 4 bonds, which means that the basic shape for most organic compounds is a tetrahedron. This also means that carbon can bond in many different ways with the same elements. H H H H (ex) H – C – C – O – H and H – C – O – C – H H H H H Both have a molecular formula of: However, they are different compounds because they have different structures. This means that they have different properties. This is called an isomer. C2H6O

Structural Formula CH3 CH2 CH2 O CH3 C4H10O This means that we CANNOT just write the molecular formula for an organic compound because we still will not know what compound it is. We have to be able to indicate the structure. Structural Formula: To show an organic compound, we can either draw a structural formula H H H H (ex) H – C – C – C – O – C – H OR we can write a condensed structural formula that still shows the order of the elements in the compound without actually drawing the bonds. (ex) What would the molecular formula be? CH3 CH2 CH2 O CH3 C4H10O

Properties of Hydrocarbons Another name for an organic compound that only contains C and H is a hydrocarbon. Hydrocarbons have specific properties. Hydrocarbons are generally… Nonpolar and therefore insoluble in water (remember “like dissolves like” and water is polar) Nonpolar molecules form LDF’s as IMF’s which are weak. (Remember London Dispersion Forces – LDF, get stronger with larger molecules) (ex) Which would most likely be a gas? CH4 or C8H18 Weak IMF’s mean that hydrocarbons generally have low melting points and boiling points.

Families of hydrocarbons Any group of hydrocarbons that have the same basic structure are called a homologous series or an organic family.  Look at Table Q. Carbon can make single bonds (1 shared pair of electrons). H H H (ex) H – C – C – C – H Hydrocarbons with all single bonds are called alkanes and have a general formula of CnH2n+2.

Families cont’d Carbon can make double bonds (2 shared pair of electrons). H (ex) H – C= C – C – H H H H Hydrocarbons with a double bond are called alkenes and have a general formula of CnH2n. Carbon can make triple bonds (3 shared pair of electrons). Hydrocarbons with a triple bond are called alkynes and have a general formula of CnH2n-2.

Families cont’d Carbon can make a ring structure. (ex) Hydrocarbons with a ring structure and alternating single and double bonds are called aromatics and have a general formula of CnHn. (while any straight chain of hydrocarbons is called aliphatic.) Carbon can make a network structure. Some hydrocarbons with a network structure are Nanotubes Buckminster fullerene (bucky balls) Diamonds Graphite

Saturated vs Unsaturated Hydrocarbons hydrocarbons with all single bonds (the carbon is saturated with H) Unsaturated hydrocarbons: hydrocarbons with double or triple bonds (the carbon could hold more H than it is holding)

Naming Hydrocarbons On Table P find the parent name by counting the number of carbon atoms in the longest straight chain. Put -ane on the end if it’s an alkane. Put -ene on the end if it’s an alkene. Put -yne on the end if it’s an alkyne. If there is a double or triple bond, we want to know where it is in the chain of carbons…so we put a number to indicate which carbon the double or triple bond is on (We want the lowest number possible). H H H (ex) H – C – C =C – C – C – H H H H H H

Branched Hydrocarbons A branched hydrocarbon contains an alkyl group which is a branch of carbon(s) coming off of a main chain of carbon atoms. (ex) – C – C – C – – C – Alkyl groups always show up as a prefix to the name of the parent chain  One carbon branch is called a methyl group Two carbon branch is called a ethyl group Three carbon branch is called a propyl group Don’t forget to indicate where on the hydrocarbon the alkyl group is by giving it a number! (Lowest number possible) (ex) 2-methylpropane

More Branched Hydrocarbons If there are 2 or more of the same alkyl groups use di, tri etc. (ex) – C – C – C – C – C – C – – C – – C – If there are 2 different alkyl groups, they must be put into ABC order. (ex) – C – C – C – C – C – C – C – – C –

Isomers Two compounds with the same molecular formula (# of C, H, and O atoms) but different structure. As the compound gets bigger, there are more possible arrangements for the atoms and therefore more possible isomers Butane has 2 isomers. Octane has 18 isomers. Decane has 75 isomers.

3 Isomers of pentane (ex) pentane

Are the following isomers of each other? – C – Isomers Practice Are the following isomers of each other? – C – (ex) – C – C – C – C – C – C – – C – C – C – C – C –

Isomers? – C – C – C – (ex3) – C – (ex2) – C – C – C – – C –

What is a Functional Group? An atom or group of atoms bonded to a hydrocarbon that gives it specific properties. IUPAC means International Union for Pure and Applied Chemistry. ** Most of the time, we will only deal with one functional group at a time. Therefore, we will be naming by changing the suffix of the name to indicate the functional group. However if there are multiple functional groups on the parent chain, the most important functional group is the suffix and least important of the functional groups are named as prefix.

IUPAC Naming Prefix- Parent-Infix-Suffix (ex 2-chloropropanol Parent: Tells the number of carbon atoms in the longest chain. Tells whether the parent chain is an alkane, alkene, or alkyne. Tells what the most important functional group is (with the lowest #) Tells the remaining functional groups on the parent chain in ABC order.

IUPAC Naming **All prefixes have to be put in ABC order. ** The number always goes before the functional group it refers to. ** Name the parent chain and then take the “e” off and add the suffix of the functional group.

Functional Groups Amide: Used in plastic, rubber, paper, and acrylic paints Name ends in -amide H H H O (ex) H – C – C – C – C – N – H H H H H O (ex) CH3CH2CH2CH2CNH2 (ex) Why don’t we have to write #’s for amides?

Functional Groups Aldehyde: Used for preservation. Aldehydes are responsible for the fresh taste of most foods. Name ends in -al H O (ex) H – C – C – H H O (ex) CH3CH2CH2CH2CH (ex) Why don’t we have to write #’s for aldehydes?

Functional Groups Ketone: Produced by our bodies as we burn fat. Used by our bodies as a source of energy when we don’t have food. Used as a solvent. Name ends in -one H H H O H (ex) H – C – C – C – C – C – H H H H H H O H (ex) H – C – C – C – H H H O (ex) CH3CH2CCH2CH2CH3 (ex) Why is ethanone not possible?

Functional Groups Alcohol: Used in producing organic acids and for fuel. Name ends in -ol H H H H Primary alcohol: (ex) H – C – C – C – C – O – H H H H H OH Secondary alcohol: (ex) – C – C – C – OH Tertiary alcohol: CH3 OH (ex) – C – C – C – C – C – C – An alcohol group attached to a carbon that is bonded to only one other carbon An alcohol group attached to a carbon that is bonded to two other carbons An alcohol group attached to a carbon that is bonded to three other carbons

Functional Groups Organic Acid: Used in flavorings, food and candy to get a sour taste. Used to make buffers and neutralize bases. Name ends in –oic acid (ex) CH3CH2COOH O (ex) – C – C – OH (ex) – C – OH

Functional Groups Ester: Used in food flavorings. It is the chemical that is responsible for the smell of flowers and fruits and perfumes. Esters are also in TNT. Name the alcohol end (single bonded O) as an alkyl group. Name the organic acid end and change the ending to -oate. O (ex) CH3CH2C – O – CH2CH2CH3 (ex) -C– C – C – O – CCH3

It is the functional group in amino acids. It is in caffeine. Functional Groups Amine: It is the functional group in amino acids. It is in caffeine. Name ends in -amine (ex) CH3CH2NH2 (ex) – C – C – C – N –

Functional Groups Ether: Used to be used as an anesthetic. Name both ends like an alkyl group and put in ABC order. Name ends in -ether. (ex) CH3OCH2CH3 **Table R is wrong. (ex) CH3CH2OCH2CH3

Functional Groups Halide: Used in refrigerants and produced by car exhaust. CFC (chlorofluorocarbons) are chemicals that break down the ozone. Name begins in chloro, fluoro, bromo, iodo. H H H H (ex) H – C – C – C – C – H H H Cl H Cl (ex) – C – C – C = C I Cl F (ex) – C – C – C – C – C – C – C – I F

Organic Reactions Because organic compounds have a different structure than other types of molecular compounds, they undergo different types of reactions. There are 7 general types of organic reactions. **Don’t forget to balance after writing the products of any reaction.

Occur when a hydrocarbon and O2 react. Complete Combustion Combustion reaction: Occur when a hydrocarbon and O2 react. Complete combustion: Occurs when there is more than enough O2 present. Products are always CO2 and H2O. (ex) C6H14 + O2  (ex) CH4 + O2 

Incomplete Combustion Occur when there is NOT enough O2 present, and therefore the products that are made contain less O2. Products are CO and H2O or C and H2O. (ex) C6H14 + O2  CO + H2O (ex) C4H10 + O2  C + H2O

Substitution Reactions Occur when we have a saturated hydrocarbon (alkane) plus a halogen. Products are a halocarbon and an acid from group 17. (ex) – C – + F – F  (ex) CH3CH3 + Br2 

Addition Reactions Addition reaction: Occur when we have an unsaturated hydrocarbon (alkene or alkyne) plus a halogen. Product is 1 halocarbon. (ex) – C – C – C = C – + Br – Br  (ex) CH2CH2 + I2 

Fermentation Reactions Occur when we have a sugar (CnH2nOn) plus an enzyme or yeast (ends in -ase). Products are ethanol and CO2. (ex) C11H22O11 (ex) C6H12O6 zymase yeast

Esterification Reactions Esterification (making esters) reaction: Occur when we have an organic acid plus an alcohol. Occurs by dehydration synthesis. Products are an ester and H2O. O (ex) – C – C – C – OH + HO– C – C –  (ex) – C – OH + HO – C – C – C – C – 

Saponification Saponification (making soap) reaction: Occur when we have a fat plus a strong base. Products are glycerol ( 1, 2, 3- propantriol) and 3 soap molecules (which is a metal bonded to a fatty acid). O (ex) – C – O – C – C20H41 – C – O – C – C20H41 + 3KOH  – C – O – C – C20H41

Polymerization Polymerization (making polymers) reaction: Polymer: any organic substance with repeating units Monomer: basic organic unit of any polymer Occurs when monomers bond together in a long chain to make a polymer. Addition polymerization: Occurs when you have an unsaturated hydrocarbon. The double or triple bond is broken and used to bond the monomers together in a long chain. Product is a polymer. (ex) n(CH2 = CH2) 

Condensation Polymerization Occurs when you have a monomer with 2 functional groups. Occurs by dehydration synthesis. Product is a polymer. (ex) HO – C – C – OH + HO – C – C – OH 

Proteins and Amino Acids polymers of amino acids. Amino Acids: Have 2 functional groups: amine and organic acid. O (ex) NH2 – CH – C – OH R α carbon Amine group Organic acid side chain (determines the amino acid)

Amino Acids There are about 20 amino acids in the human body. The difference between these amino acids is the R group. Here are some examples. O O (ex) NH2 – CH – C – OH (ex) NH2 – CH – C – OH CH3 CH2 – ALA (alanine) O (ex) NH2 – CH – C – OH CH2 – SH TRY (tryptophan) CYS (cystein) O O (ex) NH2 – CH – C – OH (ex) NH2 – CH – C – OH CH2CHCH3 CH2 – CH3 LEU (leucine) PHE (phenylalanine) NH

Making Proteins **Due to the fact that amino acids have 2 functional groups, they polymerize using condensation polymerization. H O H O (ex) H – N – CH – C – OH + H – N – CH – C – OH  R R Called a dipeptide

Types of Polymers Natural polymers: hair, cellulose (wood), cotton, DNA, proteins, starch, silk Synthetic Polymers: nylon, polyester, plastics