PPT-Chapter 4: Alkenes and Alkynes

Unsaturated Hydrocarbons Unsaturated hydrocarbon contains one or more carboncarbon double or triple bonds alkene contains a carboncarbon double bond and has the general formula C n. And 57375en 57375ere Were None meets the standard for Range of Reading and Level of Text Complexity for grade 8 Its structure pacing and universal appeal make it an appropriate reading choice for reluctant readers 57375e book also o57373ers students 1 Chemical Tests for Alkanes, Alkenes, and Aromatic Compounds Introduction There are four types of hydrocarbons : alkanes, alkenes, alkynes, and aromatic compounds, each type with different chemical Objectives. Rules. Unsaturated. Alkenes. I certainly learnt to call ethylene . ethene. and propylene . propene. (see slide 1). Molecular formula. Alkanes. C. n. H. 2n+2. Alkenes. C. n. H. 2n. Alkynes?. Orbitals. Natural gas?. Fig. 11.1. Aliphatic Hydrocarbon Structure Comparison. Bonding and Geometry. of Two-Carbon Molecules . 11.1 Structure and Physical. . Properties. The relative stabilities of related alkenes can be determined by measuring their heats of combustion.. The thermodynamic stability of the butenes increases in the order: 1-butene < cis-2-butene < trans-2-butene.. In a reaction catalyzed by mercuric ion, water can be added to alkynes to give enols, which then tautomerize to give ketones.. Hydration follows Markovnikov’s rule—terminal alkynes give methyl ketones:. Preparation of alkenes. Preparation of alkenes continued. Dehydration of alcohols. The H and OH are removed from adjacent carbons.. E.g. ethanol may be heated with . sulphuric. acid to create . ethene. Hydrocarbons . Essential idea. Structure, bonding and chemical reactions involving functional group inter-conversions are key strands in organic chemistry.. Learning outcomes . Understand:. Alkanes. have low reactivity and undergo free-radical substitution reactions.. Addition Reactions. Addition is the opposite of elimination.. Here are some of the many addition reactions that will be considered.. Addition . Reactions. Addition of Halogens. to Alkenes. +. . X. 2. 11-1. Alkenes are characterized by the presence of a double bond.. The general formula of an alkene is C. n. H. 2n. , the same as for a cycloalkane.. Common nomenclature for alkenes replaces the corresponding alkane suffix –ane with -ylene. . 11-2. The double bond consists of sigma and pi components.. Ethene is planar. It contains two trigonal carbon atoms having bond angles close to 120. o. . . The hybridization of the carbon atoms is best described as sp. . H—. O. H. C. C. +. O. H. C. C. H. Acid-Catalyzed Hydration of Alkenes. reaction is acid catalyzed; typical hydration medium is 50% H. 2. SO. 4. -50% H. 2. O. Follows Markovnikov's Rule. H. ydrohalogenation. Newehy. Chemistry Department, College of Science, King Saud University. http://fac.ksu.edu.sa/melnewehy. Unsaturated Hydrocarbons. Alkynes. - . Alkynes. are . ydrocarbons. . that contain a . carbon–carbon . Division of Material. Alkenes and Alkynes are very versatile molecules in Organic Chemistry. As a result, there is a lot of information we need for them. . To make it manageable, the information is divided into two chapters..