grade12 OrganicChemistry

ORGANIC CHEMISTRY Homologous Naming Reactions of Reactions of The study of compounds containing carbon except Objectives Introduction Series Compounds Alkanes Alkanes Alkenes Alkenes carbonates, the allotropes and oxides of carbon.

ORGANIC CHEMISTRY Homologous Naming Reactions of Reactions of Objectives Introduction Alkanes Alkenes Series Compounds Alkanes Alkenes After you have completed the viewing of this tutorial, you will be able to: • Recall that carbon forms branched and unbranched chains and ring compounds • Illustrate that carbon atoms can form single bonds, double bonds and triple bonds • List the general characteristics of a homologous series • Write general and molecular formulae for members of a given homologous series • Write formulae to represent simple organic compounds • Describe the reactions of alkanes and alkenes • Write equations for the reactions of alkanes and alkenes.

ORGANIC CHEMISTRY Homologous Naming Reactions of Reactions of Objectives Introduction Alkanes Alkenes Series Compounds Alkanes Alkenes 1. It has 4 electrons in its outer shell 2. It can bond to 4 other atoms. 3. It can form single, double and triple bonds. C-C C=C C C SINGLE BOND DOUBLE BOND TRIPLE BOND

ORGANIC CHEMISTRY Homologous Naming Reactions of Reactions of Objectives Introduction Alkanes Alkenes Series Compounds Alkanes Alkenes It can form long chains with other carbon atoms: C C C C C C C C Straight C Branched C C C C C Ring

ORGANIC CHEMISTRY Homologous Naming Reactions of Reactions of Objectives Introduction Alkanes Alkenes Series Compounds Alkanes Alkenes • Covalent bonds are usually formed in organic compounds. • Show the bonding present in methane, CH4. FEEDBACK

ORGANIC CHEMISTRY Homologous Naming Reactions of Reactions of Objectives Introduction Alkanes Alkenes Series Compounds Alkanes Alkenes H X H X C X H X H

ORGANIC CHEMISTRY Homologous Naming Reactions of Reactions of Objectives Introduction Alkanes Alkenes Series Compounds Alkanes Alkenes Organic compounds are grouped into families called homologous series. • Members can be represented by the same general molecular formula. • Members display similar chemical properties. • There is a gradual change in physical properties as the carbon chain increases. • The relative molecular mass increases by 14 as the carbon chain increases by one.

ORGANIC CHEMISTRY Homologous Naming Reactions of Reactions of Objectives Introduction Alkanes Alkenes Series Compounds Alkanes Alkenes HOMOLOGOUS SERIES GENERAL MOLECULAR FORMULA Alkanes CnH2n+2 Alkenes CnH2n Alcohols CnH2n+1OH Carboxylic Acids (Alkanoic Acids) CnH2n+1COOH

ORGANIC CHEMISTRY Homologous Naming Reactions of Reactions of Objectives Introduction Alkanes Alkenes Series Compounds Alkanes Alkenes 1. Find and name the longest continuous carbon chain. 2. Identify and name any group(s) attached to this chain. 3. Number the chain consecutively, starting at the end nearer to a substituent group. 4. Indicate the position of each substituent group by an appropriate number. 5. If there are more than one substituent then list them in alphabetical order. Note. Use the prefixes di, tri, tetra etc., to designate several groups of the same kind. These prefixes are not considered when putting substituents in alphabetical order.

ORGANIC CHEMISTRY Homologous Naming Reactions of Reactions of Objectives Introduction Alkanes Alkenes Series Compounds Alkanes Alkenes H H H H H H C C C C C H X • Find and name the longest continuous carbon chain. H H H H • Identify and name any group(s) attached to this chain. H C H • Number the chain consecutively, starting at the end nearer to a substituent group. H • Indicate the position of each substituent group by an appropriate number. • If there are more than one substituent then list them in Name of compound: alphabetical order. Use the prefixes di, tri, tetra etc., to designate several groups of the same kind. (These prefixes are not considered when putting substituents in alphabetical order.) CHECK

ORGANIC CHEMISTRY Homologous Naming Reactions of Reactions of Objectives Introduction Alkanes Alkenes Series Compounds Alkanes Alkenes H H H H H H C C C C C H X • Find and name the longest continuous carbon chain. H H H H • Identify and name any group(s) attached to this chain. H C H • Number the chain consecutively, starting at the end nearer to a substituent group. H • Indicate the position of each substituent group by an appropriate number. • If there are more than one substituent then list them in Name of compound: 2-methyl pentane alphabetical order. Use the prefixes di, tri, tetra etc., to designate several groups of the same kind. (These prefixes are not considered when putting substituents in alphabetical order.)

ORGANIC CHEMISTRY Homologous Naming Reactions of Reactions of Objectives Introduction Alkanes Alkenes Series Compounds Alkanes Alkenes H H C H H H H H H H X • Find and name the longest H C C C C C C C H continuous carbon chain. • Identify and name any group(s) attached to this chain. • Number the chain H H H H H H consecutively, starting at the end nearer to a substituent group. H C H • Indicate the position of each substituent group by an appropriate number. • If there are more than one H substituent then list them in alphabetical order. Use the prefixes di, tri, tetra Name of compound: etc., to designate several groups of the same kind. (These prefixes are not considered when putting substituents in alphabetical order.) CHECK

ORGANIC CHEMISTRY Homologous Naming Reactions of Reactions of Objectives Introduction Alkanes Alkenes Series Compounds Alkanes Alkenes H H C H H H H H H H X • Find and name the longest H C C C C C C C H continuous carbon chain. • Identify and name any group(s) attached to this chain. • Number the chain H H H H H H consecutively, starting at the end nearer to a substituent group. H C H • Indicate the position of each substituent group by an appropriate number. • If there are more than one H substituent then list them in alphabetical order. Use the prefixes di, tri, tetra etc., to designate several CHECK Name of compound: 2, 4-dimethyl heptane groups of the same kind. (These prefixes are not considered when putting substituents in alphabetical order.)

ORGANIC CHEMISTRY Homologous Naming Reactions of Reactions of Objectives Introduction Alkanes Alkenes Series Compounds Alkanes Alkenes General Molecular Formula for Alkanes: CnH2n+2 Molecular Name Relative Molecular State at room Formula Formula temperature CH4 Methane 16 gas C2H6 Ethane 30 gas C3H8 Propane 44 gas C4H10 Butane 58 gas C5H12 Pentane 72 liquid C6H14 Hexane 86 liquid C7H16 Heptane 100 liquid C8H18 Octane 114 liquid C9H20 Nonane 128 liquid C10H22 Decane 142 liquid

ORGANIC CHEMISTRY Homologous Naming Reactions of Reactions of Objectives Introduction Alkanes Alkenes Series Compounds Alkanes Alkenes Draw the structural formula of butane. FEEDBACK

ORGANIC CHEMISTRY Homologous Naming Reactions of Reactions of Objectives Introduction Alkanes Alkenes Series Compounds Alkanes Alkenes You should realize there are two ways of drawing the structural formula of butane: H H H H H H H H C C C C H H C C C H H H H H H H H C H H Continue

ORGANIC CHEMISTRY Homologous Naming Reactions of Reactions of Objectives Introduction Alkanes Alkenes Series Compounds Alkanes Alkenes Both structures have four carbon atoms and ten hydrogen atoms, i.e. they have the same molecular formula but different structural formula. They are called ISOMERS. H H H H H H H H C C C C H H C C C H H H H H H H H C H H Continue

ORGANIC CHEMISTRY Homologous Naming Reactions of Reactions of Objectives Introduction Alkanes Alkenes Series Compounds Alkanes Alkenes ISOMERS are compounds with the same molecular formula but different structural formula. Name the compounds below. H H H H H H H H C C C C H H C C C H H H H H H H H C H H Name of compound: Name of compound: CHECK

ORGANIC CHEMISTRY Homologous Naming Reactions of Reactions of Objectives Introduction Alkanes Alkenes Series Compounds Alkanes Alkenes ISOMERS are compounds with the same molecular formula but different structural formula. Name the compounds below. H H H H H H H H C C C C H H C C C H H H H H H H H C H H methylpropane or butane 2-methylpropane

ORGANIC CHEMISTRY Homologous Naming Reactions of Reactions of Objectives Introduction Alkanes Alkenes Series Compounds Alkanes Alkenes Combustion Halogenation Cracking Click on a reaction name to proceed.

ORGANIC CHEMISTRY Homologous Naming Reactions of Reactions of Objectives Introduction Alkanes Alkenes Series Compounds Alkanes Alkenes When an alkane burns in excess air, carbon dioxide and water are produced. ALKANE + EXCESS OXYGEN CARBON DIOXIDE + WATER Examples: CH4(g) + 2O2 (g) CO2 (g) + 2H2O (g) 2 C2H6 (g) + 7O2 (g) 4 CO2(g) + 6H2O(g) Combustion Halogenation Cracking

ORGANIC CHEMISTRY Homologous Naming Reactions of Reactions of Objectives Introduction Alkanes Alkenes Series Compounds Alkanes Alkenes Write balanced equations for the combustion of butane and pentane in excess air. FEEDBACK Combustion Halogenation Cracking

ORGANIC CHEMISTRY Homologous Naming Reactions of Reactions of Objectives Introduction Alkanes Alkenes Series Compounds Alkanes Alkenes Balanced equations for the combustion of butane and pentane in excess air: 2 C4H10(g) + 13O2 (g) 8CO2 (g) + 10H2O (g) Butane C5H12(g) + 8O2 (g) 5CO2(g) + 6H2O(g) Pentane What substances do you think can be produced if an alkane is burnt in a limited supply of air? Check your answers. Ask your teacher. Combustion Halogenation Cracking

ORGANIC CHEMISTRY Homologous Naming Reactions of Reactions of Objectives Introduction Alkanes Alkenes Series Compounds Alkanes Alkenes LIGHT has to be present for Halogenation to take place. The reaction takes place in a series of steps: SHOW ME CH4 (g) + Cl2 (g) CH3Cl (g) + HCl (g) CH3Cl (g) + Cl2 (g) CH2Cl2 (g) + HCl (g) CH2Cl2 (g) + Cl2 (g) CHCl3 (g) + HCl (g) CHCl3 (g) + Cl2 (g) CCl4 (g) + HCl (g) Try and name the products. Combustion Halogenation Cracking

ORGANIC CHEMISTRY Homologous Naming Reactions of Reactions of Objectives Introduction Alkanes Alkenes Series Compounds Alkanes Alkenes Cracking is the process by which long hydrocarbon chains are broken into smaller, more useful hydrocarbons. e.g. C12H26 (l) C7H16 (l) + C5H10 (l) Note that the number of carbon atoms in the products adds up to the number of carbon atoms in the reactant. The same is true for the hydrogen atoms. Complete the equation of the reaction and name the products. C18H38 C10H22 + ________ FEEDBACK Combustion Halogenation Cracking

ORGANIC CHEMISTRY Homologous Naming Reactions of Reactions of Objectives Introduction Alkanes Alkenes Series Compounds Alkanes Alkenes C18H38 C10H22 + C8H16 decane octene Combustion Halogenation Cracking

ORGANIC CHEMISTRY Homologous Naming Reactions of Reactions of Objectives Introduction Alkanes Alkenes Series Compounds Alkanes Alkenes • Characterized by the presence of a C-C double bond (C=C) • General Molecular Formula: CnH2n Molecular Formula Name Relative Molecular Formula State at room temperature C2H4 Ethene 28 gas C3H6 Propene 42 gas C4H8 Butene 56 gas C5H10 Pentene 70 liquid C6H12 Hexene 84 liquid C7H14 Heptene 98 liquid C8H16 Octene 112 liquid C9H18 Nonene 126 liquid C10H20 Decene 140 liquid

ORGANIC CHEMISTRY Homologous Naming Reactions of Reactions of Objectives Introduction Alkanes Alkenes Series Compounds Alkanes Alkenes Note there are three isomers of butene:

ORGANIC CHEMISTRY Homologous Naming Reactions of Reactions of Objectives Introduction Alkanes Alkenes Series Compounds Alkanes Alkenes Alkenes undergo ADDITION reactions. Combustion Hydrogenation (Burning) (Reaction with Hydrogen) Hydration Halogenation (Reaction with water) (Reaction with a halogen) Click on a reaction name to proceed.

ORGANIC CHEMISTRY Homologous Naming Reactions of Reactions of Objectives Introduction Alkanes Alkenes Series Compounds Alkanes Alkenes Just as with alkanes, when alkenes burn in excess air, carbon dioxide and water are produced. ALKENE + EXCESS OXYGEN CARBON DIOXIDE + WATER e.g. C2H4 (g) + 3O2 (g) 2CO2 (g) + 2H2O (g) 2C3H6 (g) + 9O2 (g) 6CO2 (g) + 6H2O (g) Write balanced equations for the combustion of butene and pentene in excess air. Combustion Hydrogenation Hydration Halogenation (Burning) (Reaction with Hydrogen) (Reaction with water) (Reaction with a halogen)

ORGANIC CHEMISTRY Homologous Naming Reactions of Reactions of Objectives Introduction Alkanes Alkenes Series Compounds Alkanes Alkenes Alkenes react with hydrogen in the presence of a nickel catalyst at 150 oC to produce the corresponding alkane. H H H H Ni C C +H H 150 oC H C C H H H H H ethene ethane C2H4 (g) + H2 (g) Ni C2H6 (g) 150 oC Combustion Hydrogenation Hydration Halogenation (Burning) (Reaction with Hydrogen) (Reaction with water) (Reaction with a halogen)

ORGANIC CHEMISTRY Homologous Naming Reactions of Reactions of Objectives Introduction Alkanes Alkenes Series Compounds Alkanes Alkenes Alkenes react with water in the presence of phosphoric acid at 300 oC to produce the corresponding alcohol. H H H H H3PO4 C C + H OH H C C H 300 oC H H H OH ethene water H3PO4 ethanol C2H4 + H2O 300 oC C2H5OH Combustion Hydrogenation Hydration Halogenation (Burning) (Reaction with Hydrogen) (Reaction with water) (Reaction with a halogen)

ORGANIC CHEMISTRY Homologous Naming Reactions of Reactions of Objectives Introduction Alkanes Alkenes Series Compounds Alkanes Alkenes Alkenes react readily with halogens, even in the dark. H H H H + Br Br H C C H C C H H Br Br ethene Bromine 1,2-dibromoethane C2H4 (g) + Br2 (aq) C2H4 Br2 (l) This reaction is used to distinguish between saturated and unsaturated compounds. Combustion Hydrogenation Hydration Halogenation (Burning) (Reaction with Hydrogen) (Reaction with water) (Reaction with a halogen)

ORGANIC CHEMISTRY Homologous Naming Reactions of Reactions of Objectives Introduction Alkanes Alkenes Series Compounds Alkanes Alkenes Click on the link below and test yourself on alkanes and alkenes. http://www.gcsescience.com/q/qhyalk.html