Alkenes Unsaturated hydrocarbons that

Alkenes Unsaturated hydrocarbons that contain a carbon-carbon double bond. 

Alkenes (olefins) are unsaturated hydrocarbons that contain carbon-carbon double bonds. A double bond consists of a cr bond and a tt bond. A tt bond is weaker than a a bond, and this makes tt bonds more reactive than cr bonds. Thus, it bond is considered to be a functional group. Alkenes form a homologous series with general molecular formula C H2 . The simplest members of the series are ethene (C2H4), propene (CsHg), butene (C4Hg) and pentene (CsHjo)-... 

In contrast to alkanes, which have only single bonds, alkenes and alkynes have multiple bonds Alkenes are hydrocarbons that contain a carbon-carbon double bond, and alkynes are hydrocarbons that contain a carbon-carbon triple bond. Both groups of compounds are unsaturated, meaning that they have fewer hydrogens per carbon than the related alkanes. Ethylene (H2C = CH2), for example, has the formula C2H4, whereas ethane (CH3CH3) has the formula C2H6. 

O aikene an unsaturated hydrocarbon that contains at least one double bond between two of the carbon atoms in the chain the simplest aikene is ethene, CjH4 O homologous series a family of organic compounds with similar chemical properties as they contain the same functional group alkenes, alcohols, for instance O isomers molecules with the same molecular formula but different stnictural formulae O substitution reaction a reaction in which one or more hydrogen atoms in a hydrocarbon are replaced by atoms of another element... 

Carbon is tetravalent (forming four bonds) and can form single bonds, double bonds, and triple bonds. As seen in Table 12.1, the four types of hydrocarbons are alkanes (single bonds), alkenes (double bonds), alkynes (triple bonds), and aromatic. Aromatics are unsaturated hydrocarbons that have cyclic structures. A common and representative compound for aromatic is benzene. 

Alkenes are hydrocarbons that contain one or more carbon-carbon double bonds. Because they contain fewer hydrogens than alkanes with the same number of carbons, alkenes are often referred to as unsaturated. 

Unsaturated hydrocarbons that contain one or more double covalent bonds between carbon atoms in a chain are called alkenes. Because an alkene must have a double bond between carbon atoms, there is no 1-carbon alkene. The simplest alkene has two carbon atoms double-bonded to each other. The remaining four electrons— two from each carbon atom—are shared with four hydrogen atoms to give the molecule ethene (C2H4). 

Alkenes are unsaturated hydrocarbons that contain a carbondouble bond, i.e., two adjacent carbon atoms are joined by two bonds. Alkenes have the general formula C H2 , where n is an integer greater than 1. The simplest member of the alkene family is C2H4 (lUPAC name ethene common name ethylene)... 

Alkenes are unsaturated hydrocarbons that contain at least one C=C bond. The simplest alkene is CH2=CH2, called ethene (lUPAC) or ethylene, which plays important roles as a plant hormone in seed germination and fruit ripening. The next member of the series is CH3 — CH = CH2, called propene or propylene. Alkenes with four or more carbon atoms have several isomers. For example, the alkene C4H8 has the four structural isomers shown in A FIGURE 24.7. Notice both their structures and their names. 

An alkene is an unsaturated hydrocarbon that contains a carbon-carbon double bond. The general formula of an alkene is... 

The series of unsaturated hydrocarbons that contain just one double bond in the structural formula of each of its members is the analogous series known as the alkenes. Notice that the name of the analogous series is similar to the analogous series of saturated hydrocarbons known as... 

Alkenes are unsaturated hydrocarbons that contain carbon-carbon double bonds (C = C). 

Aliphatic framework molecules most common in organic acids include alkanes (saturated hydrocarbons) and alkenes (unsaturated hydrocarbons). These saturated and unsaturated aliphatic carboxylic acids may be acyclic (straight or branched chains) or alicyclic (aliphatic rings). Acyclic aliphatic monocarboxylic acids are also referred to as fatty acids (Table 1). The first five saturated acids (formic to valeric) of this type are sometimes referred to as short-chain, low-molecular-weight, or volatile fatty acids. Although a nomenclature for these acids has been established by the International Union of Pure and Applied Chemistry (lUPAC), the convention of using the trivial names for the first five saturated acids has remained. Similarly, trivial names are used for the aliphatic dicarboxylic acids (Table 2) that are saturated with two to four carbon atoms (C2-C4) and unsaturated with four carbon atoms (C4). Alicyclic carboxylic acids contain one or more saturated or partially unsaturated rings. These acids most commonly occur... 

It has been known for more than a century that hydrocarbons containing double bonds are more reactive than their counterparts that do not contain double bonds. Alkenes are, in general, more reactive than alkanes. We call electrons in double bonds 71 electrons and those in the much less reactive C—C or CH bonds Huckel theory, we assume that the chemistry of unsaturated hydrocarbons is so dominated by the chemistry of their double bonds that we may separate the Schroedinger equation yet again, into an equation for potential energy. We now have an equation of the same fomi as Eq. (6-8), but one in which the Hamiltonian for all elections is replaced by the Hamiltonian for Ji electrons only... 

Alkenes are unsaturated hydrocarbons and react with substances that add to the dou... 

Alkenes — Also known as olefins, and denoted as C H2 the compounds are unsaturated hydrocarbons with a single carbon-to-carbon double bond per molecule. The alkenes are very similar to the alkanes in boiling point, specific gravity, and other physical characteristics. Like alkanes, alkenes are at most only weakly polar. Alkenes are insoluble in water but quite soluble in nonpolar solvents like benzene. Because alkenes are mostly insoluble liquids that are lighter than water and flammable as well, water is not used to suppress fires involving these materials. Because of the double bond, alkenes are more reactive than alkanes. 

One may inquire whether the evidence that 77-allyl complexes yield desorbed olefins when formed from dienes and hydrogen, or from alkenes, is pertinent to the question concerning the course of the exchange of such complexes formed by the adsorption of saturated hydrocarbons. The composition of the surface must be different under the two circumstances in one there must be few sites not occupied by olefin or half-hydrogenated intermediates, while in the other (the exchange of saturated hydrocarbons) many sites must be vacant. Consequently, in the absence of an excess of any unsaturated hydrocarbon, there is no driving force for the desorption (or displacement) of the unsaturated intermediates which are formed on the surface and intermediates of any degree of unsaturation remain bonded to the surface and leave it only as saturated hydrocarbon. Yet the evidence obtained from the reactions of the unsaturated hydrocarbons must indicate the paths which may be traversed under either circumstance. 

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