Unit Vocabulary: o Organic Acid o Alcohol. o Ester o Ether. o Amine o Aldehyde

Transcription

1 Unit Vocabulary: Addition rxn Esterification Polymer Alcohol Ether Polymerization Aldehyde Fermentation Primary Alkane Functional group Saponification Alkene Halide (halocarbon) Saturated hydrocarbon Alkyne Hydrocarbon Secondary Amide Isomer Substitution rxn Amine Ketone Tertiary Amino acid Monomer Unsaturated hydrocarbon Dehydration synthesis Organic acid Ester Organic chemistry Unit Objectives: 1. Identify organic compounds versus inorganic compounds based on structure, name, or characteristics of an unknown compound 2. Recognize the characteristics of organic compounds 3. Differentiate between aliphatic, aromatic, saturated, and unsaturated compounds Name organic compounds based on IUPAC rules, with the help of table P and Q 4. Draw organic compounds from a IUPAC name 5. Distinguish between alkynes, alkenes, and alkanes Name and identify isomers 6. Identify various functional groups of organic compounds using Table R: o Halide (halocarbon) o Organic Acid o Alcohol o Ester o Ether o Amine o Aldehyde o Amide o Ketone 7. Categorize various organic reactions properly including addition, substitution, polymerization, esterification, fermentation, saponification, and combustion. 1

2 I. Organic Chemistry: the study of compounds that contain CARBON II. Properties of Organic Compounds A. Mostly nonpolar B. Solubility: most are INSOLUBLE in water a. LIKE DISSOLVES LIKE C. Conductivity: a. mostly NON CONDUCTORS (s), (l), & (aq) states b. Only ORGANIC ACIDS IONIZE in solution = POOR CONDUCTORS D. Melting/boiling points: a. WEAK IMF s LOW MP s/bp s E. Reactivity Rate: III. Bonding a. REACT SLOWLY i. covalent molecules tend to have relatively HIGH # OF BONDS MORE STEPS in reaction rxn takes longer A. Carbon has 4 VALENCE ELECTRONS and can form 4 bonds C **carbon- always has 4 bonds around it (8 electrons) hydrogen- always has 1 bond around it (2 electrons) B. These 4 single bonds spread out evenly to create a TETRAHEDRAL molecule (like a tripod) degrees, 3-D (on paper, 2- D) 2

3 C. Carbon atoms SHARE ELECTRONS with other carbon atoms, forming COVALENT CHAINS, RINGS, and NETWORKS; Chains of carbon atoms can be open or closed, or even form three-dimensional networks. D. SATURATED HYDROCARBONS - all SINGLE BONDS between carbons (MAXIMUM number of HYDROGENS attached) a. When 1 pair of electrons is shared between two carbon atoms the bond is called a single covalent bond. E. UNSATURATED HYDROCARBONS - at least one MULTIPLE BOND in carbon chain a. If carbon atoms share two pairs of electrons the bond is called a double covalent bond. b. Carbons can even share three pairs of electrons. This bond is called a triple covalent bond. 3

4 IV. Types Of Chemical Formulas A. Molecular Formula: shows the # OF ATOMS of each ELEMENT in a compound; least informative formula B. Structural Formula: shows the # OF ATOMS of each ELEMENT AND the ARRANGEMENT of the ATOMS; most informative formula C. Condensed Formula = COMBINATION of both STRUCTURAL and MOLECULAR formulas; each carbon is written with its constituent hydrogens followed by the proper subscript Methane Ethane Molecular Formula Structural Formula Condensed Formula Ball-and-Stick Model Space-Filling Model 4

5 V. HOMOLOGOUS SERIES of Hydrocarbons: A. a group of RELATED COMPOUNDS in which each member differs from the one before it by ONE CARBON UNIT B. Three Groups: a. Alkanes: i. hydrocarbons with single covalent bonds ii. general formula= iii. example: iv. follows IUPAC naming rules-name ends in- v. shows isomerism starting with member of the series b. Alkenes: i. hydrocarbons with double covalent bonds ii. if you have 2 double bonds, it is called a iii. general formula= iv. example: v. follows IUPAC naming rules-name ends in- vi. shows isomerism starting with member of the series c. Alkynes: i. hydrocarbons with triple covalent bonds ii. general formula= iii. example: 5

6 iv. follows IUPAC naming rules-name ends in- v. shows isomerism starting with member of the series VI. Structural Formula: A. Straight Chains: also referred to as n-alkanes ( normal alkanes); n-alkenes, n-alkynes example: B. Branched: not a straight continuous chain; organic molecule that has smaller branches coming off a longer continuous chain example: VII. Nomenclature (IUPAC Naming): A. Straight Chains of Hydrocarbons a. prefixes (Table P)-dependent on the number of C's b. suffixes (Table Q)-dependent on the types of bonds 6

7 B. Branched Hydrocarbons a. the root name is that of the longest continuous chain of C atoms (aka: main chain) b. any branches off the main chain are called substituents c. the main chain is numbered so that the substituents receive the lowest possible numbers i. each substituent receives a name and a number to locate it 1. prefix corresponds to number of carbons (Table P) 2. suffix-always "-yl" ii. substituents are listed in alphabetical order iii. when more than one of the same substituent is present use the appropriate prefix (di=two, tri=three) d. Unsaturated Hydrocarbons i. the double or triple bond must be included in the main chain. ii. when numbering with substituents, the bond gets the lowest possible number. Example 1: Example 2: 7

8 VIII. Drawing Structural Formulas of Hydrocarbons: Alkanes: Example: Pentane 1. Determine the number of carbons and draw that many in a row 2. Because the molecule name ends in ane you know that there are only single bonds. Connect all of the carbons with a single line. 3. Each carbon atom must have 4 bonds connected to it. Add enough hydrogens so that each carbon has 4 total bonds connected to it. 4. Use the molecular formula to make sure that you have the correct number of hydrogens. Draw the structural formula for propane: Alkenes: 1. Determine the number of carbons and draw Example: 3-Pentene that many in a row connected by a single line. 2. Because the molecule name ends in ene you know that there is a double bond. The name of the molecule will tell you where that bond is located. For example, 2-butene will tell you that there are 4 carbons and the double bond is located after the second one. Add another line for the double bond. 3. Each carbon atom must have 4 bonds connected to it. Add enough hydrogens so that each carbon has 4 total bonds connected to it. 4. Use the molecular formula to make sure that you have the correct number of hydrogens. 8

9 Draw the structural formula for 4-hexene: Alkynes 1. follow the same rules as alkenes, except there is a triple bond, not a double bond. Draw the structural formula for 2-butyne: IX.Isomers As the number of carbon atoms increases, the number of possible isomers increases. The letter n before the name of a hydrocarbon signifies that it is the normal, or straight chain isomer. Branched isomers must have different names. Naming Isomers: The rules for naming organic compounds are governed by the International Union of Pure and Applied Chemistry (IUPAC). 9

10 Procedure: 1. Find the longest continuous chain of carbons and use its name as the base. (Example: 4 carbons = butane) 2. Count the number of carbons in the side branch and assign a prefix based on the name of the corresponding alkane. (Example: 1 carbon = methane = methyl) Alkane Alkyl Group C - C - C - C C C - C - C - C C -butane C - C - C - C C methylbutane Methane Ethane Propane Methyl Ethyl Propyl C 1 - C 2 - C 3 - C 4 C 2-methylbutane 3. If necessary, the location of the side branch (alkyl group) is shown by assigning numbers to the carbons in the longest chain. Numbering should begin at the end that has the side chain attached to the lowest number possible. (Example: 2-methylbutane, not 3-methyl butane) 4. If more than 1 side branch is attached commas are used to separate the numbers in the name and prefixes are used to denote more than one of the same group, such as 2,2-dimethylbutane: 10

11 X. Functional Groups Table R Organic compounds in which one or more hydrogen atoms of a hydrocarbon are replaced by other elements Halocarbons (Halides) - Organic compounds in which one or more hydrogen atoms are replaced by a halogen (Group 17 element) - Naming Same as hydrocarbons, but add a prefix to signify which halogen is attached. Example: - 5 carbons, singly bonded = - Bromine is present on the st and th carbons. - There are Bromines. - Well, the first half would be named 1, 4 dibromo - The final name is Name the following halocarbons: a. b. 11

12 Alcohols - Organic compounds in which one or more hydrogen atoms are replaced by an -OH group. (No more than one OH can be attached to a carbon) - They are not bases! (Do not form -OH ions in aqueous solution!) - Naming Same as hydrocarbons, but drop the e ending and add ol (For example: methanol, 2,2-dimethylbutanol...) Primary alcohols - One OH group is attached to a carbon on the end of a chain. - Represented by R-OH, where R is a hydrocarbon chain of any length Typical example = methanol = CH 3 OH 1 carbon -OH Name the following alcohols: a. CH 3 CH 2 OH b. CH 3 CH 2 CH 2 OH Secondary Alcohols: - One OH group is attached to a secondary carbon atom. (A carbon attached to 2 other carbons) 12

13 Tertiary Alcohol: - One OH is attached to a tertiary carbon atom. (A carbon attached to 3 other carbons) * Alcohols can also be classified by the number of hydroxyl groups attached to the carbon chain. Dihydroxy (2 OH s) and Trihidroxy (3 - OH s) Alcohols contain 2 and 3 hydroxyl groups, just as their names state. Draw the following molecules: 1. 2-chloro, 2-propanol 2. 2-fluoro, 1,2-butanediol 13

14 The Carbonyl Group One of the most functional groups in chemistry, which consists of a carbon atom connected to an oxygen atom by a double bond. Organic Acids A family of organic compounds containing the functional group COOH. Organic acids are formed by: 1. Dropping the final e of the alkane member. 2. Replace the e with - oic. 3. Then add the word acid. Example: Methane Methanoic Acid Ethane Ethanoic Acid Name this acid: 14

15 Aldehydes - The carbon of the carbonyl group is bonded to at least one hydrogen atom. - Named by adding the suffix -al to the name of the parent hydrocarbon. Name this aldehyde: Ketones - Has no hydrogen atoms directly attached to the carbonyl group - Named by adding the suffix -one to the name of the parent hydrocarbon. Name this ketone: 15

16 Esters - Made from an organic acid and an alcohol, resulting in: - Naming use the names of the component alcohol and acid and add the suffix -oate. - Have strong aromas; responsible for the odors of many foods and flavorings Example: = Methylpropanoate Ethers ether - General formula R 1 O R 2 where each R represents a carbon chain - Commonly named by naming the two branches first and adding the word Example: = diethyl ether Name this ether: Amines - Formed when 1 or more hydrogens in ammonia (NH 3 ) are replaced by an alkyl group - Named by changing the e ending of the alkane name to amine and adding a number to show the location of the amine group 16

17 Example: = dimethylamine Name this amine: Amides - Basically organic acids where the OH is replaced by an amine group - Named by changing the e ending of the alkane name to amide and adding a number to show the location of the amine group Example: = ethanamide Name this amide: 17

18 XI.Organic Reactions- COMBUSTION - When saturated hydrocarbons (like methane) react with oxygen at a high temperature they produce carbon dioxide and water complete combustion CH 4 + 2O 2 CO 2 + 2H 2 O - If there is insufficient oxygen, carbon monoxide is produced incomplete combustion. 2CH 4 + 3O 2 2CO + 4H 2 O Write the balanced reaction for the complete combustion of propane: SUBSTITUTION REACTION - The replacement of one kind of atom or group by another kind of atom or group. - An example of this occurs in saturated hydrocarbons where a hydrogen is replaced. - If the hydrogen is replaced by a halogen (F,Cl, Br, I, At) halogenation is said to have occurred. Name these compounds: 18

19 ADDITION REACTION - The adding of one or more atoms or groups at a double or triple bond. - The double or triple bond is changed to a single (saturated) bond or double bond. - If hydrogen is added, the process is referred to as hydrogenation. This reaction is done on unsaturated hydrocarbons, such as vegetable oils, to make the oils solidify at room temperature: saturated fats tend to be solid at higher temperatures than unsaturated fats. Name these compounds: ESTERIFICATION - Organic acids (COOH) react with alcohol s to produce an ester plus water. - The process is reversible and slow: Esterification = acid + alcohol ester + water - Esterification is also referred to as a hydrolysis (adding water) and is considered to be a dehydration reaction (removing water) or condensation (water product). Name these compounds: + + water 19

20 SAPONIFICATION - The hydrolysis of an ester such as fat with an inorganic base to produce an alcohol and a soap. FERMENTATION - Chemical process where molecules are broken down. - For example, zymase, an enzyme (which act as catalysts) from yeast, breaks down glucose to form ethanol (the alcohol we drink) and carbon dioxide (carbonation.) POLYMERIZATION - A polymer is a large molecule composed of many repeating units called monomers. - In polymerization, a number of smaller monomers join to form a larger polymer. - Natural polymers: proteins, cellulose, starch - Synthetic polymers: polyethylene, nylon and polyester. 20

21 CONDENSATION POLYMERIZATION - Monomers are joined by a dehydration reaction of two alcohols whereby water is released and an ester linkage is formed. - This will continue to grow as additional monomers attach to the dimer. - Polyester is formed this way. ADDITION POLYMERIZATION - Joining of unsaturated monomers to form long chains - The double or triple bonds are reduced to single or double bonds just like we learned earlier in addition reactions. - The letter n is used to denote that the monomer unit repeats. 21