Unit 13: Organic Chemistry

Organic Chemistry Organic chemistry is the study of carbon containing compounds Carbon is unique because it almost always forms four bonds

Hydrocarbons The simplest organic compounds, containing only hydrogen and carbon, are called hydrocarbons Hydrocarbons that have only single bonds are called saturated hydrocarbons

Alkanes An alkane is a saturated hydrocarbon with no double or triple bonds Each bond is with another carbon atom or a hydrogen atom Straight-chain alkanes have all the carbons bonded in one long chain All alkanes have the formula CnH(2n + 2) Examples: CH4, C4H10 To name straight-chain alkanes, use the prefixes in Table P and add -ane

Practice Problem Draw the structural formula for each straight-chain alkane below and then name them C2H? C5H? C7H?

Alkanes Alkanes are ______________ molecules that will not dissolve in water The melting point and boiling point of alkanes increase with the size of the molecule due to increasing _______________________ forces Alkanes combust easily with oxygen and are a common component in fuels

Practice Problem Match the alkane on the left with its correct boiling point on the right CH4 174°C C5H12 -162°C C10H22 36°C

Alkanes Branched-chain alkanes have carbons attached to the central parent chain Compounds that have the same molecular formula but different structural formulas are called isomers

How to name branched-chain alkanes Count the carbons in the parent chain (the longest chain) and use the corresponding alkane name Number the carbons in the parent chain starting with the one closest to the branch chain Name each branch with a –yl ending and place it before the name of the parent chain Use the number of the carbon to which it’s attached to indicate the branch’s position (if necessary)

Practice Problem Name the molecule below

Practice Problem Name the molecule below

Practice Problem Name the molecule below

Practice Problem Name the molecule below

Aim: How do we name and draw structures for alkenes and alkynes?? Do Now: Draw the structural formulas for two isomers of C4H10 Homework 13.1: Worksheet entitled, “Naming Hydrocarbons”

Group-Pair Share Problem Give the structural formula, condensed structural formula, and molecular formula for 4-propyloctane

Group Pair Share Problem Give the structural formula, condensed structural formula, and molecular formula for 2-methylhexane

Group Pair Share Problems Draw all isomers of pentane Draw all isomers of hexane

Alkenes and Alkynes Hydrocarbons that contain double and triple bonds are called unsaturated hydrocarbons Compounds with double bonds between carbons are called alkenes Alkenes have the formula CnH2n Alkynes are compounds with triple bonds between carbons Alkynes have the formula CnH(2n – 2)

Label the following compounds as alkanes, alkenes, or alkynes Practice Problem Label the following compounds as alkanes, alkenes, or alkynes C3H4 C8H18 C6H12

How to name alkenes and alkynes Count the carbons in the parent chain and use the corresponding alkane name Change the ending to –ene or -yne 2. Number the carbons in the parent chain starting with the one closest to the double or triple bond 3. Use the number of the carbon where the bond starts to indicate the bond’s position

Name the compound below: Practice Problem Name the compound below:

Name the compound below Practice Problem Name the compound below

Group-Pair Share Problem Name the compounds below:

Aim: How do we name and draw structures for alkenes and alkynes? Do Now: Copy general rules for naming hydrocarbons. Homework 13.1: Worksheet entitled, “Naming Hydrocarbons” Quiz: TOMORROW!! (On drawing hydrocarbon structures)

Group-Pair Share Problems Give the structural formula, condensed structural formula, and molecular formula for 3-octene Give the structural formula, condensed structural formula, and molecular formula for 1-butyne

Branched Unsaturated Hydrocarbons With unsaturated hydrocarbons that have attached groups, the longest chain containing the double (or triple) bond is considered the parent chain.

Name the following: This vertex represents a carbon bonded to two hydrogen atoms Structural Formulas are sometimes represented by skeletal structures. A skeletal structure usually shows the carbon framework of a molecule only as lines representing bonds Carbon atoms are understood to be at each bond, along with enough hydrogen atoms so that each carbon makes four bonds

Hint: Start by filling in carbon and hydrogen atoms Name the following: Hint: Start by filling in carbon and hydrogen atoms

Aim: How are functional groups named? Do Now: Remove everything from your desk except for: Pen/pencil Reference table

Quiz # 10 Version A complete questions: 2, 4, 6 Version B complete questions: 3, 5, 7

Cycloalkanes Alkanes that are connected in a loop are called closed- chain alkanes or cycloalkanes They are named by using the prefix cyclo- and the name of the straight-chain alkane with the same number of carbons

Aromatic Hydrocarbons Benzene is a six carbon ring with alternating single and double bonds Compounds that contain benzene rings are called aromatic compounds Compounds without benzene rings are called aliphatic The hexagon represents the six carbon atoms and the circle represents the delocalized electrons

Draw C4H6 as a cycloalkene Practice Problem Draw C4H6 as a cycloalkene

The symbols R and R’ represent bonded atoms or groups of atoms Functional Groups Atoms other than hydrogen and carbon occur in organic molecules as functional groups The symbols R and R’ represent bonded atoms or groups of atoms

Halocarbons When any of the halogens (F, Cl, Br, or I) replaces a hydrogen, the compound is called an organic halide They are named by citing the location of the halogen and the type of halogen on the chain

They are not polar enough to dissolve in water Halocarbons Because of the high EN _________________ of halogens, organic halides are slightly polar They are not polar enough to dissolve in water The boiling points of halocarbons are slightly higher than the corresponding alkane

Name the compound shown below Practice Problem Name the compound shown below

Group-Pair Share Problem Draw the structure of 4-iodononane

Aim: How are functional groups named? Do Now: Draw the structures for: 3,3- dimethyl-1-butyne 3-ethyl-2,4,5-trimethyloctane

–OH is called a hydroxyl group (not to be confused with OH-!) Alcohols –OH is called a hydroxyl group (not to be confused with OH-!) When a hydroxyl group is attached to an organic molecule it is called an alcohol Alcohols are named by adding –ol to the parent chain and using a number to indicate the location

Alcohols with five carbons or less are completely soluble in water Alcohols have hydrogen bonding and are much more polar than their parent alkanes Alcohols with five carbons or less are completely soluble in water

Group-Pair Share Problem Draw the structural formula for 1-butanol

Name the compounds below: Practice Problem Name the compounds below:

Ethers An ether is an organic compound containing an oxygen atom bonded to two carbon atoms Ethers are named by listing the two groups attached before the word ether If the two groups attached are the same the ether is named by putting di- in front

Draw the structure of methylpropyl ether Practice Problem Draw the structure of methylpropyl ether

Name the compound below Practice Problem Name the compound below

Organic Joke Two hydrocarbons were in the cafeteria having lunch and talking. One hydrocarbon brings up “Methyl Ethyl” the school gossip. Methyl Ethyl had a reputation for causing problems between the hydrocarbons. The two hydrocarbons finished their lunches and started to head to their next class. One hydrocarbon turns to the other and says, “Yeah that Methyl Ethyl is a bad egg, I don’t like her.” The other hydrocarbon says, “Yeah, I don’t like Methyl Ethyl Ether”

Many functional groups are based around a carbonyl group: Carbonyl Compounds The arrangement in which an oxygen atom is double bonded to a carbon atom is called a carbonyl group Many functional groups are based around a carbonyl group: Aldehydes Ketones Carboxylic Acids Esters Amides

Aldehydes An aldehyde is an organic compound with a carbonyl group located on a terminal carbon Aldehydes are named by adding –al to the name of the parent chain Aldehydes are polar, but slightly less so than alcohols or amines

Draw the structure of propanal Practice Problem Draw the structure of propanal

Group-Pair Share Problem Name the compound below:

Ketones are slightly polar A ketone is a compound in which the carbonyl group is on a central carbon Ketones are named by adding –one to the parent chain and using a number to indicate the position of the oxygen Ketones are slightly polar

Name the compound below: Practice Problem Name the compound below:

Group Pair Share Problem Draw the structure of 2-hexanone

Aim: How are functional groups named? Do Now: Draw the structural formulas for: 3-heptanone 3,3-diethyl-2,5-dimethylnonane 1,1,1,2- tetrabromobutane

Carboxylic Acids Carboxylic acids, also called organic acids, have a carbonyl group bonded to a hydroxyl group (called a carboxyl group) They are named with the suffix –oic acid They are very polar, weak acids

Name the compound below: Practice Problem Name the compound below:

Group Pair Share Problem Draw the structure of propanoic acid

Esters A compound formed by replacing the hydrogen in a carboxyl group with a hydrocarbon is called an ester An ester is named by naming the hydrocarbon group followed by the name of the acid but changing –oic acid to – oate

Name the compound below Practice Problem Name the compound below

Group Pair Share Problem Draw the structure of methyl butanoate

Group Pair Share Questions Name the following compounds:

Amides are named by adding –amide to the parent chain When the hydroxyl group of a carboxylic acid is replaced with a nitrogen atom, the result is an amide Amides are named by adding –amide to the parent chain

Draw the structure of methanamide Practice Problem Draw the structure of methanamide

Name the compound below Practice Problem Name the compound below

Amines Amines contain nitrogen atoms bonded to carbon atoms They are named with the suffix –amine Amines are slightly less polar than alcohols They often have strong, offensive odors (like dead fish)

Group-Pair Share Problem Name the compound below

Draw the structure of ethanamine Practice Problem Draw the structure of ethanamine

Amino acids have an amine group and a carboxylic acid They can bond together in long chains to form proteins and are essential for all life

Substitution Reactions A substitution reaction is one in which one atom or group of atoms is replaced by another atom or group of atoms The most common organic substitution reaction is when a hydrogen is replaced by a halogen

Write a possible reaction between chlorine and propane Practice Problem Write a possible reaction between chlorine and propane

They are essentially the reverse of elimination reactions Addition Reactions Addition reactions are when a double or triple bond is broken by the addition of atoms to both sides of the bond They are essentially the reverse of elimination reactions

Write the following reaction: HCl is added to 2-hexene Practice Problem Write the following reaction: HCl is added to 2-hexene

Write the following reaction: I2 is added to propyne Practice Problem Write the following reaction: I2 is added to propyne

Group Pair Share Problem Explain why alkanes do not undergo addition reactions.

Esterification Reactions In an esterification reaction, an organic acid and an alcohol combine to form an ester and water

Practice Problem Write the reaction between ethanoic acid and 1-butanol and name the product

Write the reaction for the synthesis of methyl ethanoate Practice Problem Write the reaction for the synthesis of methyl ethanoate

The products are always CO2 and H2O Combustion Reactions In a combustion reaction, oxygen combines with hydrocarbons releasing energy in the form of heat and light The products are always CO2 and H2O

Write the reaction for the combustion of propane Practice Problem Write the reaction for the combustion of propane

Fermentation The process in which glucose is broken down into ethanol is known as fermentation Yeasts and some bacteria ferment glucose to produce ethanol, carbon dioxide, and energy

The product of the reaction, an organic salt, is soap Saponification The reaction of a triglyceride, which is a triple ester, with a base is called saponification The product of the reaction, an organic salt, is soap

Plastics, synthetic fibers, and rubber are all examples of polymers Polymerization Polymers consist of smaller molecules bonded together by a series of chemical reactions Plastics, synthetic fibers, and rubber are all examples of polymers The reaction in which small organic units, called monomers, are bonded together into a very large molecule is called a polymerization reaction

Polymerization

Polymerization

Group Pair Share Questions Classify the following compounds as an alcohol, carboxylic acid, aldehyde, ketone, ester, or ether.

Group Pair Share Questions Name or draw the following compounds:

Group Pair Share Questions Draw structural formulas for the following compounds: Butanoic acid 2,2-dichloro-1,1-difluoropropane 3,4-dimethylpentanal 2,3-butanediol