VII. Organic Organic Chemistry deals with carbon molecules attached to hydrogen and other elements. Properties of Organic Compounds Low melting points and boiling points. Longer chains have higher melting and boiling points Nonpolar (vdw forces) React Slowly Poor conductors of heat & electricity except for organic acids J Deutsch 2003 8 It can form up to 4 covalent bonds with other carbon atoms and make single double or triple bonds with itself. Hydrocarbons Compounds containing only carbon & hydrogen Saturated hydrocarbon Hydrocarbon containing only single carbon-carbon bonds Unsaturated hydrocarbon Hydrocarbon containing at least 1 double or triple carbon-carbon bond Homologous Series A group of related compounds in which each member differs from the one before it by the same additional unit. Properties vary in a predictable way. Table Q gives the general formula and examples (name and structure) of the homologous series of hydrocarbons. J Deutsch 2003 14 Table P gives the prefix used to name the first 10 hydrocarbons in an homologous series. J Deutsch 2003 15 Alkanes saturated hydrocarbons. All single bonds general formula CnH2n+2. end in “ane” Regents Question: 01/03 #25 In saturated hydrocarbons, carbon atoms are bonded to each other by (1) single covalent bonds, only (2) double covalent bonds, only (3) alternating single and double covalent bonds (4) alternating double and triple covalent bonds J Deutsch 2003 17 Alkenes Unsaturated Hydrocarbon Contain one double bond CnH2n End in “ene” # in front may give location of double bond. Alkynes Unsaturated hydrocarbon Contain one triple bond CnH2n-2 End in “yne” # in front gives location of triple bond. In a multiple covalent bond, more than one pair of electrons are shared between two atoms. Alkenes have one double bond H H C C H Ethene C2H4 H Alkynes have one triple bond H J Deutsch 2003 C C H Ethyne C2H2 20 Chains of carbons can form rings Use a prefix cyclo when a ring is formed To make a ring, two Hydrogen atoms are removed Cyclopentane is a 5 carbon ring with all single bonds. J Deutsch 2003 21 The prefix of the name tells you how many carbons in the chain.The suffix tells you the type of hydrocarbon. J Deutsch 2003 Example Number of Carbons Prefix 1 Meth 2 Eth 3 Prop 4 But 5 Pent Alkane CnH2n+2 Methane CH4 Ethane C2H6 Propane C3H8 Butane C4H10 Pentane C5H12 Alkene CnH2n Ethene C2H4 Propene C3H6 Butene C4H8 Pentene C5H10 Alkyne CnH2n-2 Ethyne C2H2 Propyne C3H4 Butyne C4H6 Pentyne C5H8 22 Regents Question: 06/03 #24 Which element has atoms that can form single, double, and triple covalent bonds with other atoms of the same element? (1) hydrogen (2) oxygen (3) fluorine (4) carbon J Deutsch 2003 23 Regents Question: 06/03 #21 Which hydrocarbon is saturated? (1) propene (2) ethyne (3) butene (4) heptane Alkanes are saturated hydrocarbons. J Deutsch 2003 24 A structural formula show the way the atoms are arranged. Methane Ethane H H C H J Deutsch 2003 H H H H C C H H Each line represents a covalent bond - a shared pair of electrons. H 25 A structural formulas show the way the atoms are arranged. propene H H H C C H ethyne H J Deutsch 2003 C The double bonds makes this hydrocarbon an alkene C H C H The triple bonds makes this hydrocarbon an alkyne H 26 Carbon always has 4 bonds. Hydrogen always has 1 bond Oxygen always has 2 bonds Nitrogen always has 3 bonds C or H J Deutsch 2003 O C or or O C N 27 The 4 single bonds of a carbon atom are directed to … the corners of a regular tetrahedron. Chemical or Molecular Formulas Tell the kind & number of atoms in a molecule. Regents Question: 01/03 #13 The empirical formula of a compound is CH2 Which molecular formula is correctly paired with a structural formula for this compound? J Deutsch 2003 30 Regents Question: 08/02 #42 Which structural formula is incorrect? Carbon always has four bonds. J Deutsch 2003 31 Naming hydrocarbons with alkyl groups: Find the longest continuous chain of carbons. This is the backbone. Find the name of the backbone. Find the name of the alkyl group (or groups) attached to the backbone. Name the alkyl group and then the name of the backbone. Use a number to indicate which carbon the alkyl group is attached to if necessary. J Deutsch 2003 32 Chains of carbons can be branched A carbon group connected to a chain is called an alkyl group. To name the alkyl group, use the prefix for the number of carbons and add yl. -CH3 -C2H5 J Deutsch 2003 H H H C H H C H Methyl H C H Ethyl 33 Find the name of this hydrocarbon. H H H H H C H H H H C C C C C C H 1 6 2 5 3 4 4 3 5 26 1 H H H H H H Find the longest chain 3- methyl hexane Find the alkyl group Counting from each direction find the carbon where the alkyl group is attached (the lower number) J Deutsch 2003 34 The longest chain does not have to be drawn straight. H H C H H C H H H H H H C C C C C H H H H H H 3-methylhexane J Deutsch 2003 35 Isomers of organic compounds have the same molecular formula but different structures and properties. (3.1ii) Pentane C5H12 H H H H H H C C C C C H H H H H Methylbutane C5H12 H H H H H H C C C C H H H H H C H H J Deutsch 2003 36 Isomers # of possible isomers as # of C atoms Regents Question: 08/02 #55 Given the structural formula for butane: Draw the structural formula for an isomer of butane. H H H H C C C H H H H C H H J Deutsch 2003 38 Regents Question: 06/03 #25 Which compound is an isomer of pentane? (1) butane (2) propane (3) methyl butane (4) methyl propane J Deutsch 2003 39 Regents Question: 01/03 #18 Which compound has an isomer? J Deutsch 2003 40 Regents Question: 06/02 #19 Which formula is an isomer of butane? J Deutsch 2003 41 J Deutsch 2003 Organic acids, alcohols, esters, aldehydes, ketones, ethers, halides, amines, amides, and amino acids are categories of organic molecules that differ in their structures. Functional groups impart distinctive physical and chemical properties to organic compounds. (3.1hh) 42 Reference Table R lists all the functional groups. J Deutsch 2003 43 Reference Table R Cont’d. J Deutsch 2003 44 Naming Alcohols (-OH) Alcohols have the hydroxyl group -OH The prefix is the number of carbons in the longest chain – Name the alkane and drop the letter e The suffix is ol If there are more than 2 carbons in the chain, use a number to indicate which carbon the –OH group is attached to. (Number from the direction that gives the smallest number) 1-propanol H J Deutsch 2003 H H OH C C C H H H 2-propanol H H H OH H C C C H H H H 45 Regents Question: 08/02 #20 Which compound is an alcohol? (1) propanal (2) ethyne (3) butane (4) methanol J Deutsch 2003 46 Naming Ethers (-O-) Ethers have an Oxygen in the chain of carbons Name the alkyl groups on either side of the O that is in the chain If both alkyl groups are the same it is named once with the prefix DI in front of it. Methyl ethyl ether H J Deutsch 2003 H H C C H H Dimethyl ether H O C H H H H H C O C H H H 47 Naming Aldehydes (-CHO) Aldehydes have a double bonded Oxygen on the last carbon in the chain. Name the alkane, drop the e and add __al propanal H J Deutsch 2003 H H O C C C H H methanal O H H C H 48 Naming Ketones (-CO-) Ketones have a double bonded Oxygen on a carbon in the middle of the chain. (Not the last carbon) Name the alkane, drop the e and add __one If there are more than 4 carbons in the chain, use a number to indicate the location of the =O butanone H J Deutsch 2003 3-pentanone H H O H C C C C H H H H H H H O H H C C C C C H H H H H 49 Naming Organic Acids (-COOH) Acids have a double bonded Oxygen and an –OH on the last carbon in the chain. Name the acid, drop the e and add __oic acid This is OH and not HO…the Carbon is bonded to the O Propanoic acid H J Deutsch 2003 H H C C C H H Pentanoic acid O OH O H H H H HO C C C C C H H H H H 50 Regents Question: 06/03 #44 Given the formulas of four organic compounds: Which pair below contains an alcohol and an acid? J Deutsch 2003 (1) a and b (3) b and d (2) a and c (4) c and d 51 Naming Esters (-COOC-) Esters have a double bonded Oxygen and an –O– bonded to another carbon. Name the alkyl group that came from the alcohol. Name the acid but drop __ic acid and replace it with ate. Propanoic acid + pentanol Pentyl propanoate + water Propanoic acid H J Deutsch 2003 H H C C C H H 1-Pentanol O OH H H H H H HO C C C C C H H H H H H 52 Naming Halocarbons (-X) Halocarbons (or halides) have a halogen (F, Cl, Br, I) in place of a hydrogen Name the halogen first (fluoro, chloro, bromo, iodo) then name the alkane If there are more than 2 carbons in the chain, use a number to indicate which carbon the –X group is attached to. (Number from the direction that gives the smallest number) H J Deutsch 2003 1-chloropropane 2-bromobutane H H Cl H Br H H C C C C C C C H H H H H H H H H H 53 Naming Amines (-NH2) Amines have a nitrogen bonded to the carbon chain. The nitrogen may have two, one or no hydrogen atoms bonded to it. Name the alkane, drop the e and add __amine If there are more than two carbon atoms, use a number to indicate which carbon the N is attached to. ethanamine H J Deutsch 2003 H H C C NH2 H H 2-Pentanamine H NH2 H H H H C C C C C H H H H H H 54 Name the folowing: H H C O C H H H O C C OH H H C C C H H O H H H C C C H H H 3-hexanone J Deutsch 2003 H H C C C N H H H H 1-Propanamine H H H H H C C C C H H 2-butene H Ethanal H H Ethanoic acid H H H H H H OH H H H H C C C C C H H H H H H 2-pentanol 55 Examples of isomers: 1-butanol (C4H9OH) diethyl ether (C2H5OC2H5) 4 Carbon, 10 Hydrogen, 1 Oxygen propanal (C2H5CHO) 2-propanone (CH3COCH3) 3 Carbon, 6 Hydrogen, 1 Oxygen Isomers have the same chemical formulas but different structural formulas. J Deutsch 2003 56 Regents Question: 06/02 #17 Which compound is classified as a hydrocarbon? (1) Ethane (2) Ethanol (3) chloroethane (4) ethanoic acid J Deutsch 2003 57 Regents Question: 06/02 #48 Which pair of compounds are alcohols? J Deutsch 2003 58 Regents Question: 01/03 #49 Which type of organic compound is represented by the structural formula shown below? (1) aldehyde (2) alcohol (3) ether (4) ester J Deutsch 2003 59 Types of organic reactions include: addition, substitution, polymerization, esterification, fermentation, saponification, and combustion. (3.2c) J Deutsch 2003 60 Organic Reactions-Addition Addition – H2, Cl2, Br2, HCl, HBr is added to an unsaturated hydrocarbon. Both atoms are added to where the double (or triple) bond was located. – Key to look for – Unsaturated hydrocarbon reactant and one product. H H C H J Deutsch 2003 C + Cl2 H H Cl Cl C C H H H 61 Organic Reactions-Addition Cont’d Addition of hydrogen H2 Can be used to saturate and unsaturated hydrocarbon. It uses a catalyst such as platinum (Pt) H H C H J Deutsch 2003 C + H2 H H H C C H H Pt H H 62 Regents Question: 01/03 #26 Which formula correctly represents the product of an addition reaction between ethene and chlorine? (1) CH2Cl2 (2) CH3Cl (3) C2H4Cl2 (4) C2H3Cl J Deutsch 2003 63 Organic Reactions-Substitution Substitution – A halogen is reacted with a saturated hydrocarbon. One of the halogen atoms substitutes one of the hydrogen atoms. – Key to look for – Saturated hydrocarbon reactant and two product. H H J Deutsch 2003 H C C H H H + Cl2 UV H H Cl C C H + HCl H H 64 Organic Reactions-Polymerization Polymerization – joining many small molecules together to form a large molecule – A single unit is called a monomer – Many monomers are bonded together to form a polymer – Polymers can be natural or artificial Natural Polymers Protein Rubber Cellulose J Deutsch 2003 Artificial Polymers Polyester Nylon Styrofoam 65 Regents Question: 06/02 #49 The process of joining many small molecules into larger molecules is called (1) neutralization (2) polymerization (3) Saponification (4) substitution J Deutsch 2003 66 Regents Question: 06/03 #45 Which type of reaction is represented by the equation below? Note: n and n are very large numbers equal to about 2000. J Deutsch 2003 (1) Esterification (3) saponification (2) fermentation (4) polymerization 67 Organic Reactions-Esterification Esterification – making an ester by combining an alcohol with an organic acid H H J Deutsch 2003 H H C C H H H H C C H H OH + HO O H C C H H O O H C C H + H2O H 68 Making an ester by removing water from an acid and an alcohol Propanoic acid H 1-Pentanol H H O H H H H H C C C OH HO C C C C C H H H H H H H H Pentyl propanoate J Deutsch 2003 69 Name the ester: Methyl ethanoate H O H C H Ethanoate Acid C H O C H H Alcohol Methyl Determine which side was the alcohol and which side was the acid by drawing a line through the oxygen in the chain. The side with the double bonded O was the acid. Alcohol will make you yl if you ate the acid. J Deutsch 2003 70 Regents Question: 08/02 #56 Given the ester: ethyl butanoate a. Draw the structural formula for this ester. b. Determine the gram formula mass of this ester. C 6 x 12 = 72 H H H O H H H C C C H H H C O C H C H O 2 x 16 = 32 H H 12 x 1 = 12 Even if you got the structure wrong but you got the correct mass for the structure you drew, you got one point. J Deutsch 2003 116 g 71 Amides (-CON) are made by reacting an organic acid with ammonia or with an amine. H H O C C H N H H From ammonia (NH3) J Deutsch 2003 H H O C C H H N C H H H From amine (CH3NH2) 72 Naming Amides (-CON-) Amides have a double bonded Oxygen and a Nitrogen. Name the alkyl group that came from the amine. Name the acid but drop __oic acid and replace it with amide. Propanoic acid + 1-pentanamine Pentyl propanamide + water Propanoic acid H J Deutsch 2003 H H C C C H H 1-Pentanamine O OH H H H H H H2N C C C C C H H H H H H 73 Making an amide by removing water from an acid and an amine Propanoic acid H H H O C C C H H OH 1-Pentanamine H H H H H HN C C C C C H H H H H H H Pentyl propanamide J Deutsch 2003 74 Amino acids have both an amine group and an acid group. An amino acid is a compound that has an amine group on one side and an acid group on the other. HO O R C C N H H H R is the only part that changes in different amino acids. J Deutsch 2003 75 Proteins are polymers of amino Remove water HO O R O R C C N C C H H J Deutsch 2003 N H H H HO O R C C N H H H 76 Organic Reactions-Fermentation Fermentation – yeast and bacteria can make ethanol and carbon dioxide by breaking down sugar using an enzyme. C6H12O6 Enzyme 2C2H5OH + 2CO2 – The alcohol can be used to make beer and wine, – The carbon dioxide can be used to make bread rise or make the bubbles in beer and champagne. J Deutsch 2003 77 Organic Reactions-Saponification Saponification is a reaction in which a lipid (fat or oil) is used to make soap. J Deutsch 2003 78 Organic Reactions-Combustion Combustion – Burning – Combining with oxygen to produce carbon dioxide and water J Deutsch 2003 Burning Methane CH4 + 2O2 Burning Octane 2C8H18 +25O2 Burning Ehtanol C2H5OH + 3O2 CO2 + 2H2O 16CO2 + 18H2O 2CO2 + 3H2O 79 Regents Question: 08/02 #21 In which reaction is soap a product? (1) addition (2) substitution (3) Saponification (4) polymerization J Deutsch 2003 80