Preparation of alkanes alkanes are referred to as the saturated hydrocarbons, that is, hydrocarbons having all carbon atoms bonded to other carbon atoms or hydrogen atoms with sigma bonds only. Unsaturated hydrocarbons alkenes and alkynes react with h 2 in the presence of finely divided catalysts such as platinum, palladium or nickel to form alkanes. Alkanes, alkenes, and alkynes back to previous page accredited. General methods of preparation of alkenes is the topic which has a potential of fetching a question in iit jee and jee mainadvanced examination very frequently.
Alkanes that have carbons that are bonded to more than 2 carbons these are skeletal isomers example butane. Chapter 2 alkanes key concepts nomenclature for unbranched alkanes dispersion london forces constitutional isomers nomenclature for. Alkanes and cycloalkanes 11 million organic compounds which are classified into families according to structure and reactivity functional group fg. To me it appears like a primeval tropical forest full of the most remarkable things, a dreadful endless jungle into. This reaction is known as wurtz reaction and used for the preparation of symmetrical alkanes. This is a simple process using first halogenation of the alkene bond to form the dihaloalkane, and next, using the double elimination process to protonate the alkane and from the 2 \\pi\ bonds this first process is gone over in much greater detail in the page on halogenation of an alkene.
They are used as starting materials in the syntheses of alcohols, plastics, laquers, detergents, and fuels. A bottle full of an alkane can sit forever without decomposing or reacting with airborne chemicals. Saturated hydrocarbons can also combine any of the linear, cyclic e. Substitution reactions of alkanes reaction of alkanes with bromine chlorine in uv light in the presence of uv light alkanes react with chlorine to form a mixture of products with the halogens substituting hydrogen atoms.
However, ignoring financial considerations, alkanes can be prepared from alkanes. A branched chain alkane or branched alkane is an alkane which has alkyl groups bonded to its central carbon chain. Elimination reactions alkenes olefins are hydrocarbons that contain a carboncarbon double bond and are said to be unsaturated. This section deals with wurtz reaction,frankland reaction. In my textbook, it says that alkanes are generally the least reactive of the three, alkenes are slightly more reactive, and alkynes are even more reactive. Official iupac naming recommendations are not always followed in practice, and the common or trivial name may be used. Preparations alkenes are generally prepared through.
Alkanes and cycloalkanes chapter 2 2 structure hydrocarbon. Sheets e involves some reading for information and only has a limited amount of. Alkanes are hydrocarbons that have only carboncarbon. Alkanes answers to problems 1 c and d are the same. A systematic method of naming organic chemical compounds as recommended by the international union of pure and applied chemistry iupac. Please give the iupac name for the following structures. Each of the different sheets allows for a different level of support and challenge sheet a is totally blank. Alkanes lab complete the worksheet as you build models of the different alkanes. The product is the symmetrical alkane containing twice the number of carbon atoms present in the alkyl halide. In the laboratory heat the flask, with a bunsen burner or electric mantle this causes vapours of all the components in the mixture to be produced. In other words, an alkane consists of hydrogen and carbon atoms arranged in a tree structure in which all the carboncarbon bonds are single. Learn the iupac system for naming alkanes and cycloalkanes. Pdf organic chemistry made easy for senior secondary schools.
Alkanes 2 organic chemistry nowadays almost drives me mad. Constitutional isomers exhibit different physical properties, for example, melting and boiling points. May 04, 2018 substitution reactions of alkanes reaction of alkanes with bromine chlorine in uv light in the presence of uv light alkanes react with chlorine to form a mixture of products with the halogens substituting hydrogen atoms. This is a collection of separate pdf documents that help learners summarise information about the alkanes. Preparations include the dehydration of alcohols, the dehydrohalogenation of alkyl halides, and the dehalogenation of alkanes. However, alkanes have single bonds, alkenes have double bonds, and alkynes have triple bonds. C at room temperature some alkanes are liquids, some solids and some gases done clear. Preparation of alkanes from unsaturated hydrocarbons. Naming alkanes with alkyl groups video khan academy.
Much of this fraction is utilized as jet engine fuels or is cracked to. Alkenes find many diverse applications in industry. For alkenes, alkynes and aromatic hydrocarbons, spring models can be constructed. In organic chemistry, an alkane, or paraffin a historical name that also has other meanings, is an acyclic saturated hydrocarbon. Thermal cracking involves heating alkanes to a high temperature, producing small alkanes such as ethene. Hydrocarbons are molecules composed of only hydrogen and carbon.
Alkanes when we combine the two high bond enthalpy and being nonpolar this makes alkanes quite unreactive alkanes dont react with acidsbases or oxidizing agents this is a useful trait and alkanes are used as lubricating agents and the backbone of polymers but when the do react look out. The alkanes range in complexity from the simplest case of methane. However, ignoring financial considerations, alkanes can be prepared from the following compounds. Alkanes, part 2, preparation of alkanes ismail mortada. This content is ed under the following conditions, you are granted permission for individual, educational, research and noncommercial reproduction, distribution, display and performance of this work in any format. Caserio 1977 basic principles of organic chemistry, second edition. If two structures just differ in the way the atoms are shown on the page, but not in the arrangement of the bonds, the molecules are the. The physical state of alkanes depends upon the intermolecular forces of attraction present between molecules which in turn, depend upon the surface area of the molecules. Alkanes chemistry, class 11, hydrocarbons class notes. In organic chemistry, an alkane, or paraffin is an acyclic saturated hydrocarbon. C at room temperature some alkanes are liquids, some solids and. Paraffin wax, which is made of very large alkanes, is used in home canning because it is not affected by the food being canned.
Branching of the chain in alkanes dramatically increases the diversity of conceivable structures. Alkanes from carbon and hydrogen alkanes are carbon compounds that contain only single bonds. Alkene nomenclature please read and understand prefixparentsuffix suffix for alkenes. By reduction of alkyl halides rx haloalkanes rx when heated with reducing agents like. Lastly, we will briefly look at how to prepare alkynes from alkenes.
Heres what you need to know about the branched alkanes. Learn vocabulary, terms, and more with flashcards, games, and other study tools. Some other methods for preparation of alkanes are discussed below. If two molecules can only be interconverted by breaking a bond and then reforming it somewhere else in the molecule, they are structural isomers. For making models of alkanes, you can use toothpicks for bonds and plasticine balls for atoms. How to name branched chain alkanes schoolworkhelper. The vapour of the substance with the lower boiling point reaches the top of the fractionating column first. It involves the chemical reaction between alkyl halides usually bromides and iodides and metallic sodium in the presence of dry ether. Organic chemistry university of california riverside.
Alkane names are based on the number of carbon atoms in the longest continuous chain in the compound. Alkane names, formulas, properties memorize sections. Alkanes and alkenes see online here the hydrocarbons are organic compounds classi. Determination of the % fe in an unknown by titration. Pristane is found in shark liver oil and also in sperm whale, lobster. Structures with identical molecular formulas but with different connectivities of atoms are called constitutional isomers. Pristane is found in shark liver oil and also in sperm whale, lobster, zooplankton, etc. The simplest alkanes are hydrocarbons compounds that contain only carbon and hydrogen. Catalytic cracking involves heating higher boiling point petroleum fractions in the presence of a silicabased catalyst, making shorter alkanes which can be used in petrol. Alkanes are rarely prepared from other types of compounds because of economic reasons. Organic chemistry science at yorkdale with jessica. The branched alkanes make better gasoline than their con tinuouschain isomers because they give less knock in highcompression gasoline engines. The alkanes summary flipped learning teaching resources.
This is because the cc bond and the ch bond are relatively strong. General methods of preparation of alkanes wurtz reaction. In addition to carbon dioxide, water and heat a variety of. To me it appears like a primeval tropical forest full of the most remarkable things, a dreadful endless jungle into which one does not dare enter, for there seems to be no way out. Alkanes are attracted to each other by weak intermolecular forced called dispersion forces also called london forces alkanes are relatively nonpolar, but can develop instantaneous dipoles that attract each other as the surface area of molecules increases, the dispersion forces become larger in order for a molecule to go from being a liquid. A saturated hydrocarbon whose carbons are arranged in an open chain. Preparation of alkanes from carboxylic acids, alkyl halides. If the carbons are in a row, the alkane is a straightchain alkane nalkane. For alkanes with four or more carbons, the carbons can be connected in more than one way. Alkanes are less dense than water and swim on top of water 2. Check the price hire a writer get help this chain is used as the parent structure. Cracking is the process of breaking larger alkanes into smaller alkanes. Learn the important physical and chemical properties of the alkanes. Module 3 alkanes and alkyl halides lecture 4 alkanes nptel.
Alkanes when we combine the two high bond enthalpy and being nonpolar this makes alkanes quite unreactive alkanes dont react with acidsbases or oxidizing agents this is a useful trait and alkanes are used as lubricating agents and the backbone of polymers but when the do react. Preparations include the dehydration of alcohols, the dehydrohalogenation of alkyl halides, and. Alkane names, formulas, properties memorize sections 3. Note that the alkanes with even number of carbon atoms can easily be prepared by this method. Ants and cockroaches have nundecane which is a pheromone in their bodies 11. Hydrocarbons are used mainly as fuels, solvents and lubricants.
Introduction of a halogen into a molecule chlorination, bromination general reaction. How do i identify, define and draw alkanes and alkane isomers. Naming alkanes, cycloalkanes, and bicyclic compounds. In addition to carbon dioxide, water and heat a variety of products are possible. The rotator phase is stable over a temperature interval of as much as 19c in a 79. Alkanes, hydrocarbons, class 11 the acyclic saturated hydrocarbons. It is postulated that when ants sting, the alkanes help the formic acid spread through the victims contact point 12.
Fgs behave similarly in every molecule they are part of. General methods of preparation of alkenes askiitians. In general, alkanes do not react with many reagents. The names of alkanes containing up to twelve carbon atoms per chain are as follows. Determination of an equilibrium constant using spectroscopy potassium permanganate alkanes, alkenes, and alkynes. The process is best suited for preparation of completely. Pdf on may 27, 2017, adebayo bamidele olanrewaju and others published organic. B all alkanes have a lower density than water done clear.
Ace your next assignment with help from a professional writer. Branched alkanes contain only carbon and hydrogen c and h. Find the longest continuous chain of carbons in the molecule. Number core chain from an end nearest a substituent 3.