1 Additional Structures to Accompany Exp. 16 Introduction to Models Goals: Draw formulas for alkanes from their three-dimensional models. Write the names of alkanes from their structural formulas. Construct models of isomers of alkanes. Write structural formulas for designation of functional groups. Introduction: The saturated hydrocarbon represents a group of organic compounds composed of carbon and hydrogen. Alkanes and cycloalkanes are called saturated hydrocarbons because their carbon atoms are connected by only single bonds. In each type of alkane each carbon must have four valence electrons and must always have four single bonds. To learn more about the three dimensional structure of organic compounds, it is helpful to build models using ball and stick model kit. In the kit are wooden (or plastic) spheres which represent the typical elements in organic compounds. Each wooden atom has the correct number of holes drilled for bonds that attach to other atoms. Table 16A.1 Elements and Bonds Represented in the Organic Model Kit Color Element Number of Bonds Black Carbon 4 Yellow or White Hydrogen 1 Red Red 2 Green Halogen (F, Cl, Br, or I) 1 Blue Nitrogen 3 Silver Hexavalent (not used) 6 Longer bonds or springs C, N, O Multiple (double or triple) Shorter bonds or sticks Any Single bonds 1. First we will build methane, CH4. We will also show the three ways to draw this structure. A) 3-dimensional B) Complete Structural formula C) Condensed structural formula 2 Table 16A.2 Complete the table by drawing the first 10 Alkanes: Name Condensed Complete Draw at least one formula structural isomer AND Formula name it Methane CH4 Name: _________ Ethane CH3CH3 Name: _________ Propane Name: _________ Butane Name: _________ Pentane Name: _________ Hexane Name: _________ Heptane Name: _________ Octane Name: _________ Nonane Name: _________ Decane Name: _________ 3 Table 16A.3 Fill in the table and find the functional groups: Condensed formula Full Structural Formula Organic Family (functional group) CH3-OH CH3-CH2-CH3 CH2=CH2 CH3-O-CH3 O CH3-C—OH CH3-NH2 O CH3-C-CH3 O CH3-N-CH3 CH3-CH2-CH=CH-CH3 CH3-CH2-NH-CH2-CH3 CH3-CH2-O-CH3 CH3CH2CH2COOH 4 Additional Structures to Accompany Lab 18 Structures of Alkanes Goals: To determine names and shapes of halogenated organic compounds To determine the name and shape of cycloalkanes To determine the name and shape of branched alkanes Table 18A.1 Complete the table for the haloalkane Name Complete Structural Condensed structural formula formula Chloromethane 1,2-dibromoethane 2-iodopropane Table 18A.2 Complete the table by creating four isomers of dichloropropane Name Complete structural formula Condensed structural formula 5 Table 18A.3 Complete the table by creating the cycloalkane with the appropriate number of carbons. Number of C Name Condensed Geometric atoms structure Formula 3 4 6 8 Table 18A.4 Complete the table Name Condensed Structure ethyne 2-methyl-2pentene phenol Complete Structural Formula Geometric formula (if applicable) 6 ADDITIONAL STRUCTURES FOR ALCOHOLS AND PHENOLS LAB 19 Goals: Determine chemical and physical properties of alcohols and phenols Classify an alcohol as primary, secondary, or tertiary Name and build models of various alcohols Introduction: Alcohols are organic compounds that contain the hydroxyl group (-OH). The simplest alcohol is methanol. Ethanol is found in alcoholic beverages and preservatives and is used as a solvent. Isopropanol or 2-propanol is used as a disinfectant and is found in perfumes. The abbreviations for alcohols may be MeOH for methanol or EtOH for ethanol. What would be the abbreviation for n-propanol? Table 19A.1 Fill in the table for the simple alcohols listed. Name Condensed Structure Methanol Complete Structure Ethanol Isopropanol or 2-propanol A benzene ring with a hydroxyl group is known as phenol. Concentrated solutions of phenol are caustic and cause burns. It is a weak acid that is soluble in water. However, derivatives of phenol, such as thymol, are used as antiseptics and are sometimes found in cough drops. Table 19A.2 Fill in the table for these aromatic alcohols Name Condensed Structure Phenol Complete Structure Thymol (2-isopropyl-5methylphenol) Thiols and Diols: A thiol contains an –SH group. The name is given the alkane chain name then thiol is after it as one word. Ex. CH3CH2SH is ethanethiol Diols contain TWO –OH groups. We will not be naming diols, but you should know what they are and how to recognize this functional group. 7 Classification of Alcohols: In a primary (10) alcohol, the carbon atom attached to the – OH group is bonded to one other carbon atom. In a secondary (20) alcohol, it is attached to two carbon atoms and in a tertiary (30) alcohol to three carbon atoms. Table 19A.3 Fill in the table describing if the alcohol is primary, secondary, or tertiary. Name Condensed Complete 10, 20, or 30 structure structure Ethanol t-butyl alcohol (2methyl-2-propanol 1methylcyclopentanol 3-pentanol Cyclohexanol Table 19A.4 Fill in the missing information in the table below. Name Condensed Complete formula formula 3,4 di-methylhexane 2,2,4trimethylhexane 3-ethyl2,4,5trimethylhexane 1-ethyl-3-methyl-5propylcyclohexane 4-chloro-4,5dimethyl-2-hexene Functional group or Organic family 8 ETHERS Ethers contain an oxygen atom that is attached by a single bond to two carbon groups that are alkyls or aromatic rings. Ethers have a bent structure like water and alcohols. Most ethers are named by their common names. The IUPAC names are used only when the ether is more complex. Step 1 Step 2 Step 3 For simple ethers, use the common name. Write the name of each alkyl or aryl (aromatic) group attached to the oxygen atom in alphabetical order followed by the word ether. For more complex ethers, use IUPAC naming. Use the alkane name of the larger alkyl group as the main chain. Name the oxygen and smaller alkyl group as a substituent called an alkoxy (alkyl + oxygen) group. Number the main chain beginning at the end nearest the alkoxy group and give the location of the alkoxy group on the main chain. Ex. CH3-O-CH3 = dimethyl ether (common name) Ex. -O – CH3 methoxycyclobutane (IUPAC) or cyclobutyl methyl ether (common) 19A.5 Fill in the table for the following ethers Common name IUPAC name Condensed Structure Methoxymethane Diphenyl ether Ethoxyethane 2-methoxybutane Ethyl propyl ether Complete Structure 9 Additional Structures for Lab 20 Aldehydes and Ketones Goals: Write functional groups of aldehydes and ketones Determine chemical and physical properties of aldehydes and ketones Name and create models of aldehydes and ketones Introduction: Structures of some Aldehydes and Ketones: Aldehydes and ketones contain the carbonyl group. In an aldehyde, the carbonyl group has a hydrogen attached; the aldehyde functional group occurs at the end of the carbon chain. In a ketone, the carbonyl group is located between two of the carbon atoms within the chain. Write the generic form of aldehydes: ________________________________ Write the generic form of ketones: __________________________________ Properties of Aldehydes and Ketones: Many aldehydes and ketones have sharp odors. If you have taken biology class, you may have noticed the odor of FormalinTM, which is a solution of formaldehyde. When you remove fingernail polish, you may notice the strong odor of acetone, the simplest ketone, which is used as a solvent. Aromatic aldehydes have a variety of odors. Benzaldehyde, the simples aromatic aldehyde, has an odor of almonds. Table 20A.1 Fill in the missing information in the table Name Condensed Formula Formaldehyde IUPAC name: ________ Acetaldehyde IUPAC name: ________ Acetone IUPAC name: _________ Butanone IUPAC name: _________ Cyclohexanone Complete structural formula 10 Benedict’s test is used to distinguish aldehydes from ketones. When in contact with an aldehyde the oxidiation occurs because the Cu2+ bluish ion contained in Benedict’s solution becomes a reddish Cu+ (reduced). The copper cation is reduced whereas the aldehyde is oxidized. Ketones cannot oxidize so the copper ion remains blue. Table 20A.2 Fill in the following table Name Condensed Formula Complete Structural Formula Functional Group CH3CH2CCH 3-methylcyclohexene Trans-2-pentene m-ethyltoluene 2,2,5trimethylcyclohexanol CH3CH2CH2SH Begin working on the structures in your lab practical review. Try to do as many as you can without looking up the structures.