Chemistry- Alkanes and Alkenes

The regale of appellative tangleds allows chemists to communicate phase angleulae in talking to rather than in chemical symbols. There ar, however, a few rules active naming compounds which need to be cognize in roll to create verbally a traffic pattern in word form or transform a compound in word form into chemical symbols. bonce compounds If the compound is ionic, thus the name of the cation (usually admixture) comes set-back, followed by the compound name of the anion.To find the compound name of an anion, replace the expiry of the portions name with ide. name of cation + name of anion, affix ide E. g. NaCl atomic round 11, the cation, first-year, followed by chlorine swapd with the affix ide = atomic subroutine 11 chloride If the anion is polyatomic and restricts atomic number 8, then the affix is ate. name of cation + name of polyatomic type O anion, affix ate E. g. Na2CO3 sodium, the cation, first, followed by a polyatomic meeting containing d egree centigrade and oxygen to form cytosine paperate = sodium atomic number 6ate no(prenominal)eE. g. MgO magnesium, the cation, first, followed by oxygen changed with the suffix ide beca routine oxygen is the resole ion and non part of a polyatomic crowd = magnesium oxide some(a) measure if the compound contains henry, the word enthalpy shortens to bi such(prenominal)(prenominal) as with NaHCO3, which is known as sodium total heat speed of lightate or sodium bi speed of light copyate. Hydrogen compounds If the compound contains total heat and a surface, the metal comes first, followed by the word hydride, to de n wizard the enthalpy compvirtuosont. etal + hydride E. g. NaH sodium, the metal, first, followed by atomic number 1 changed with the suffix ide = sodium hydride If the compound contains total heat and a non-metal and does non contain piddle ( piddle), then the hydrogen comes first, followed by the divisors name replaced with the ide suffix. hydrogen + no n-metal, suffix ide E. g. HF hydrogen first, followed by fluorine changed with the suffix ide = hydrogen fluoride If the hydrogen non-metal compound dissolves in piss, it tarts with the hydro affix, followed by the elements name replaced with an ic suffix, followed by red-hot. hydro(name of element, suffix ic) window pane E. g. HCl hydro, then chlorine with an ic suffix, then acid = hydrochloric acid Oxygen compounds When naming ionic compounds that contain oxygen the elemental rule is corresponding. If the compound contains hydrogen and an oxygen anion (oxyanion) and does not contain pissing, then hydrogen comes first, followed by the element name with the suffix ate. hydrogen + element, suffix ate E. g.HCO3 hydrogen followed by atomic number 6 paper with the suffix ate = hydrogen degree Celsiusate The ate rule is employ for the to the highest degree communal or the only compound made with an oxyanion. rough compounds, however, form to a greater extent than one type o f compound with oxygen and the sum up of oxygen allow affect the prefixes and suffixes habituate. This occurs for all oxyanions, with or without hydrogen involved. Table 1. 1 appointment more than one type of oxygen compound Oxygen direct Prefix Element Suffix A microscopical oxygen hypo- -ite Some oxygen -ite More oxygen -ate A disseminate of oxygen per- -ateE. g. chlorine forms four antithetic oxyanions named ClO = hypochlorite ClO2 = chlorite ClO3 = chlorate ClO4 = perchlorate The oxygen level corresponds with the relative amounts in different compounds and not necessarily the specific numbers of oxygen atoms. If an element forms incisively cardinal types of oxyanion compounds, then the suffixes ite and ate pull up stakes suffice. If the hydrogen oxyanion compound is dissolved in piddle, it forms an acid using similar rules, only the ite suffix changes to ous and the ate suffix changes to ic, followed by the word acid.Table 1. 2 Naming more than one type of hydr ogen oxyanion acid Oxygen level Prefix Element Suffix bliste resile A little oxygen hypo- -ous Some oxygen -ous More oxygen -ic A lot of oxygen per- -ic E. g. The above example with chlorine and oxygen plus hydrogen HClO = hypochlorous acid HClO2 = chlorous acid HClO3 = chloric acid HClO4 = perchloric acid covalent compounds If a compound contains two non-metals in a covalent stupefy certificate, then * the least disconfirming element is named first if the compound contains hydrogen, hydrogen is named first * the number of atoms of each element is indicated by a prefix * if the first element only has one atom the prefix is not utilize * the name of the element has the suffix ide least damaging + number prefix, most electronegative element, suffix ide The prefixes economic consumptiond to number the atoms come from Grecian and ar as follows 1 = mono- or mon- 2 = di- 3 = tri- 4 = tetra- 5 = penta- 6 = hexa- 7 = hepta- 8 = octa- 9 = nona- 10 = deca- E. g.CO snow, the least electronegative atom, first, followed by the prefix mon to indicate one atom of oxygen, the most electronegative atom, with the suffix ide = one C monoxide CO2 light speed, the least electronegative atom, first, followed by the prefix di to indicate two atoms of oxygen, the most electronegative atom, with the suffix ide = carbon dioxide weewee the prefix di to indicate two atoms of hydrogen, which has naming antecedency, followed by mon to indicate one atom of oxygen = dihydrogen monoxide Common name There ar a number of common name calling that chemists like to white plague instead of the halal scientific names. rough common names and formulae be wellspring-known. It is recommended that common names and formulae be written down as they argon en look atered so they can be memorised later. present ar a few examples Common name puritanical name Chemical formula water dihydrogen monoxide H2O baking club soda sodium hydrogen carbonate NaHCO3 table salt sodium c hloride NaCl limestone calcium carbonate CaCO3 quartz silicon dioxide SiO2 satisfy animation 1. What is an acid? antediluvian patriarch civilisations had already determine acid as a influence-ta bunko nerve that corrode metal, scarce confirmation about the exact nature of acid eluded chemists until the twentieth century.Early in the 20th century, a number of chemists developed specific chemical definitions for the term acid, although some(prenominal) of these definitions refer to subatomic processes, termination into much greater depth than required here. The simplest, most geast northeastral definition is that an acid is a substance that contains hydrogen and which can release hydrogen cations (H+) during a reaction. The speciality of an acid depends on its ability to release hydrogen ions pisseder acids release hydrogen ions more pronto. Some of the holdingerties of acid ar that they * answer in water to form excess hydrogen ions Are highly reactive and impart cor rode most metals * Conduct electricity * Have a sour judge (strong acids be dangerous and should not be taste sensation-tested) * Produce a stinging sensation (as above, strong acids should not be glide byled) There atomic number 18 some common edible acids such as citric acid, which is name in fruits like oranges, lemons and limes, acetic acid, found in vinegar, carbonic acid, which is the fizz in soft drinks and dairy harvest-tides, which contain lactic acid. Examples of other acids embroil sulfuric acid, present in batteries and hydrochloric acid, which breaks down food in your stomach. promise see 1.Acids like vinegar are applyd to preserve food beca riding habit many organisms cannot live in an acidulous environment. Similarly, fermentation of food can in like manner produce an acidic environment for preservation purposes vinegar is an acetic acid formed from grapes, lactic acid comes from fermentation of milk. What is a base? Bases are substances with the opposi te properties to acids, that is, a base is a substance that accepts hydrogen ions in a reaction. Strong bases will accept more hydrogen ions than faint nerveed ones. Alkalis are soluble bases that contain hydroxide ions (OH-). Some properties of bases include that they Dissolve in water to absorb excess hydrogen ions * Neutralise the force-out of acid * Denature (change the molecular structure) of proteins * Have a bitter taste (strong bases are dangerous and should not be taste-tested) * Feel soapy (as above, strong bases should not be handled) Basic substances in e veryday utilize include sodium hydrogen carbonate, to a fault known as sodium bicarbonate, used in baking to assist bread rise, sodium carbonate, used to find soap, and magnesium hydroxide, commonly used in indigestion remedies. Because of an ability to denature proteins, fundamental substances break down grease and make good cleaners.Considering that the piece body is made up of proteins, this makes bases more d angerous for humans than acids. miniature of terms Before proceeding, it is important to clarify some terms used in experiments with acids and bases. Strong substances are either acids that readily lose hydrogen cations or bases that readily gain hydrogen ions weak substances less readily lose or gain hydrogen ions. For clarity, concentrated acids and bases are either pure or come dissolved in very little water, firearm dilute substances are dissolved in a lot of water.Therefore, strong and weak refer to the chemical reactivity of an acidic/ elemental substance while dilute and concentrate refer to the ratio of water into which the substance dissolves. Indicators It is overly important to learn about some of the slipway in which to test the speciality of acidic and canonical substances, since it is not permitted to taste or touch chemicals in a laboratory environment. Chemical substances are classified as acidic (containing acid), basic (containing base) or neutral (containing uncomplete acid nor base). Chemists hurl developed a number of methods to test the acidity or alkalinity of a substance using chemical index numbers.These indicators use the pH measure, with measurements from one to 14 based on the activity of hydrogen ions in the solution. Substances with a low pH are acidic. Substances with a reading of s nonetheless-spot are neutral while basic solutions will elicit a high reading. Developed by Danish scientist Soren Sorensen, the pH scale whitethorn put one across come from the German word potenz (meaning power or potency) and H, the chemical symbol for hydrogen. It is withal doable the term is derived from the Latin pondus hydrogenii, which translates to weight of hydrogen. See animation 1.Many plants are excellent indicators of pH as they need optimum acidity/alkalinity in the soil to grow. Hydrangeas produce white or meritless flowers in acidic soil or pink flowers in basic soil. Blue or red litmus paper, made from a fungous/bacte rial growth called lichen, turns red in acid or soft in a base just now will not change colour in a neutral solution. A celluloid indicator, bromothymol amobarbital sodium, starts blue and then changes yellow in acid. If placed in a basic or neutral substance it will remain blue. Another indicator would be needed to find out if the substance were neutral or basic.This demonst range that when using an indicator it is necessary to observe a change in colour to define whether a substance is acidic, basic or neutral. Most indicators attain only two colours. The universal indicator is an instrument that mixes several(prenominal) types of indicators and colours in order to show whether a substance is acidic, basic or neutral. Universal indicators have a colour scale that corresponds to the numbered pH scale. After testing, the colour of the paper is matched to a number on the scale for a more exact reading of acidity or alkalinity. See image 2. ReactionsSince acids and bases are more or less opposite substances, they escape to cancel each other out in a process called neutralisation. This reaction produces a salt and water. acid + base salt + water Neutralisation is commonly used in a number of remedies, such as the treatment of bites and stings. Bluebottles inject a basic substance when they sting, so a weak acid like vinegar (acetic acid) will knock off a bluebottle sting. Conversely, bee stings are slightly acidic, so a bee sting would be kill with a weak base, such as sodium bicarbonate. Seafood joins off an odour payable to the basic amines it contains.An acidic acid substance such as lemon juice is squeezed over it to neutralise the smell. bare(a) acid in the stomach causes indigestion, so it can be neutralised with a weak base called an antacid. An example of an equating using this format is when hydrochloric acid meets sodium hydroxide to form sodium chloride and water HCl + NaOH NaCl + H2O Adding an acid to a base does not necessarily mean that the product is automatically neutralised. The strength of each of the reactants must be matched so that all the ions released by the acid find a place with the base.A strong acid with a weak base will result in an acidic salt, a weak acid with a strong base will result in a basic salt, while acids and bases of the equivalent strength will neutralise completely. Both acidic and metallic substances are highly reactive, which is why acid reacts aggressively in the presence of metal, corroding the metal much faster than moisture and air. The combination of an acid and a metal produces a metallic salt and hydrogen swash in an equation represented like this acid + metal metallic salt + hydrogen The hydrogen ions are easily lost and replaced by the metallic ions, forming a metallic salt.The hydrogen then forms molecules with itself, resulting in hydrogen gas. An example of this is sulphuric acid and magnesium producing magnesium sulphate salt and hydrogen gas H2SO4 + Mg MgSO4 + H2 No Fla sh, No Problem Highlight to reveal names Formula Names N2F6 Dinitrogen Hexafluoride CO2 hundred Dioxide SiF4 Silicon Tetrafluoride CBr4 Carbon Tetrabromide NCl3 due north Trichloride P2S3 Diphosphorous Trisulfide CO Carbon Monoxide NO2 Nitrogen Dioxide SF2 Sulfur Difluoride PF5 Phosphorous Pentafluoride SO2 Sulfur Dioxide NO Nitrogen Monoxide CCl4 carbon tetrachlorideP2O5 diphosphorus pentoxide Rules 1. The first element is named first, using the elements name. 2. Second element is named as an Anion (suffix -ide) 3. Prefixes are used to denote the number of atoms 4. Mono is not used to name the first element Note when the attachment of the Greek prefix places two vowels adjacent to one another, the a (or the o) at the end of the Greek prefix is usually dropped e. g. , nonaoxide would be written as nonoxide, and monooxide would be written as monoxide. The i at the end of the prefixes di- and tri- are never dropped. Prefix number indicated mono- 1 di- 2 tri- 3 tetra- 4 pent a- 5 hexa- 6 hepta- 7 octa- 8 nona- 9 deca- 10 Carbon Allotropes by siebo last modified April 20, 2007 1154 The allotropes of carbon are the different molecular configurations (allotropes) that pure carbon can take. Following is a list of the allotropes of carbon, ordered by notability, and extent of industrial use. Diamond primary(prenominal) phrase Diamond Diamond is one of the best known allotropes of carbon, whose asperity and high dispersion of light make it useful for industrial applications and jewelry.Diamond is the hardest known natural mineral, making it an excellent abrasive and also means a diamond holds its polish extremely well and retains luster. The market for industrial-grade diamonds operates much other than from its gem-grade counterpart. Industrial diamonds are valued mostly for their hardness and heat conductivity, making many of the gemological characteristics of diamond, including clarity and color, mostly irrelevant. This helps explain why 80% of ex ploit diamonds (equal to about 100 million carats or 20,000 kg annually), unsuitable for use as gemstones and known as bort, are destined for industrial use.In addition to mined diamonds, synthetic diamonds found industrial applications almost immediately subsequently their invention in the 1950s another 400 million carats (80,000 kg) of synthetic diamonds are produced annually for industrial usen premature four times the mass of natural diamonds mined over the comparable period. The dominant industrial use of diamond is in cutting, class perioding, grinding, and polishing. Most uses of diamonds in these technologies do not require commodious diamonds in fact, most diamonds that are gem-quality except for their beautiful size, can find an industrial use.Diamonds are embedded in drill tips or saw blades, or ground into a powder for use in grinding and polishing applications. Specialized applications include use in laboratories as containment for high pressure experiments (see diamond anvil), high-performance bearings, and limited use in specialized windows. With the continuing advances world made in the yield ofsynthetic diamond, future applications are beginning to become feasible. Garnering much excitement is the workable use of diamond as asemiconductor suitable to build microchips from, or the use of diamond as a heat sink in electronics.Significant interrogation efforts in Japan, Europe, and the United Statesare under way to capitalize on the emf offered by diamonds unequaled temporal properties, combined with increased quality and total of supply starting to become available from synthetic diamond manufacturers. each(prenominal) carbon atom in diamond is covalently cling certificateed to four othercarbons in a tetrahedron. These tetrahedrons together form a 3-dimensional network of puckered six-membered rings of atoms. This horse barn network of covalent bonds and the tierce dimensional arrangement of bonds that diamond is so strong. Gra phite of import obligate Graphite Graphite (named by Abraham Gottlob Werner in 1789, from the Greek to pressure/write, for its use in pencils) is oneof the most common allotropes of carbon. distant diamond, black lead is a conductor, and can be used, for instance, as the material in the electrodes of an galvanic arc lamp. Graphite holds the distinction ofbeing the most stable form of strong carbon ever discovered. Graphite is able to conduct electricity due to the odd fourth electron in each carbon atom. This unpaired 4th electron forms delocalisedplanes above and below the planes of the carbon atoms.These electrons are drop out to move, so are able to conduct electricity. However, the electricity is only conducted inside the plane of the layers. Graphite powder is used as a dry out lubricant. Although it might be thought that this industrially important property is due entirely to the loose interlamellar coupling among sheets in the structure, in fact in a vacuum enviro nment (such as in technologies for use in space), graphite was found to be a very piteous lubricant. This fact lead to the discovery that graphites lubricity is due to adsorbed air and water between the layers, unlike other layered dry lubricants such as second disulfide.Recent studies suggest that an effect called superlubricity can also account for this effect. When a large number of crystallographic defects bind these planes together, graphite loses its lubrication properties and becomes what is known as pyrolytic carbon, a useful material in blood-contacting implants such as prosthetic heart valves. Natural and crystalline graphites are not often used in pure form as structural materials due to their shear-planes, brittleness and ill-matched mechanical properties.In its pure glassy (isotropic) synthetic forms, pyrolytic graphite and carbon fiber graphite is an extremely strong, heat-resistant (to 3000 C) material, used in reentry shields for missile nosecones, flatforward ro cket engines, high temperature reactors, brake shoes and electric motor brushes. Intumescent or expandable graphites are used in paint a picture seals, fitted around the allowance of a fire door. During a fire the graphite intumesces (expands and chars) to resist fire penetration and prevent the spread of fumes. A typical start enlargement temperature (SET) is between 150 and 300 degrees Celsius. unformed carbon Main article Amorphous carbon Amorphous carbon is the name used for carbon that does not have any crystalline structure. As with all glassy materials, some short-range order can be observed, but there is no long-range pattern of atomic positions. While entirely unformed carbon can be made, most of the material expound as amorphous actually contains crystallites of graphite 1 or diamond 2with varying amounts of amorphous carbon holding them together, making them technically polycrystalline or nanocrystalline materials.Commercial carbon also usually contains significant q uantities of other elements, which may form crystalline impurities. combust and soot are both informally called amorphous carbon. However, both are products of pyrolysis, which does not produce true amorphous carbon under common conditions. The coal industry divides coal up into various grades depending on the amount of carbon present in the sample compared to the amount ofimpurities. The highest grade, anthracite, is about 90 percentage carbon and 10% other elements. Bituminous coal is about 75-90 percent carbon, and lignite is the name for coal that is around 55 percent carbon.Fullerenes Main article Fullerene The fullerenes are recently-discovered allotropes of carbon named after the scientist and architect Richard Buckminster Fuller, but were discovered in 1985 by a team of scientists from Rice University and the University of Sussex, three of whom were awarded the 1996 Nobel Prize in Chemistry. They are molecules composed entirely of carbon, which take the form ofa hollow sp here, ellipsoid, or tube. Spherical fullerenes are sometimes called buckyballs, while rounded fullerenes are called buckytubes or nanotubes.As of the early twenty-first century, the chemical and physical properties of fullerenes are still under heavy study, in both pure and apply research labs. In April 2003, fullerenes were under study for potential medicinal use binding specific antibiotics to the structure to target resistant bacteria and even target certain cancer cells such as melanoma. Fullerenes are similar in structure to graphite, which is composedof a sheet of linked hexagonal rings, but they contain pentagonal (or sometimes heptagonal) rings that prevent the sheet from being planar. Carbon nanotubes Main article Carbon nanotubeCarbon nanotubes are cylindrical carbon molecules with novel properties that make them potentially useful in a liberal variety of applications (e. g. , nano-electronics, optics, materials applications, etc. ). They exhibit extraordinary strength and unique electrical properties, and are efficient conductors of heat. Inorganic nanotubes have also been synthesized. A nanotube (also known as a buckytube) is a member of the fullerene structural family, which also includes buckyballs. Whereas buckyballs are spherical in shape, a nanotube is cylindrical, with at least one end typically capped with a hemisphere of the buckyball structure.Their name is derived from their size, since the diameter of a nanotube is on the order of a few nanometers(approximately 50,000 times smaller than the width of a human hair), while they can be up to several centimeters in length. There are two main types of nanotubes single-walled nanotubes (SWNTs) and multi-walled nanotubes (MWNTs). aggregated diamond nanorods Main article Aggregated diamond nanorods Aggregated diamond nanorods, or ADNRs, are an allotrope of carbon believed to be the least compressible material known to humankind, as measured by its sothermal bulk modulus aggregated diamond na norods have a modulus of 491 gigapascals (GPa), while a conventional diamondhas a modulus of 442 GPa. ADNRs are also 0. 3% denser than regular diamond. The ADNR material is also harder than type IIa diamond and ultrahard fullerite. Glassy carbon Main article Glassy carbon Glassy carbon is a class of non-graphitizing carbon which is widely used as an electrode material in electrochemistry, as well as for high temperature crucibles and as a component of some prosthetic devices.It was first produced by workers at the laboratories of The General Electric Company, UK, in the early 1960s, using cellulose as the starting material. A short time later, Japanese workers produced a similar material from phenolic resin. The preparation of glassy carbon involves subjecting the organic precursors to a series of heat treatments at temperatures up to 3000oC. Unlike many non-graphitizing carbons, they are impermeable to gases and are chemically extremely inert, particularly those which have been pr epared at very high temperatures.It has been demonstrated that the rates of oxidation of certain glassy carbons in oxygen, carbon dioxide or water vapour are lower than those of any other carbon. They are also highly resistant to attack by acids. Thus, while normal graphiteis cut down to a powder by a mixture of concentrated sulphuric and nitric acids at room temperature, glassy carbon is unaffected by such treatment, even after several months. Carbon nanofoam Main article Carbon nanofoam Carbon nanofoam is the fifth known allotrope of carbon discovered in 1997 by Andrei V.Rode and co-workers at the Australian National University in Canberra. It consists of a infrequency cluster-assembly of carbon atoms strung together in a loose cubic web. Each cluster is about 6 nanometers wide and consists of about 4000 carbon atoms linked in graphite-like sheets that are given negative curvature by the inclusion of heptagons among the regular hexagonal pattern. This is the opposite of what h appens in the outcome of buckminsterfullerenes, in which carbon sheets are given positive curvature by the inclusion of pentagons.The large-scale structure of carbon nanofoam is similar to that of an aerogel, but with 1% of the denseness of previously produced carbon aerogels only a few times the parsimony of air at sea level. Unlike carbon aerogels, carbon nanofoam is a poor electrical conductor. Lonsdaleite Main article Lonsdaleite Lonsdaleite is a hexagonal allotrope of the carbon allotrope diamond, believed to form when meteoric graphite falls to Earth. The great heat and pains of the impact transforms the graphite into diamond, but retains graphites hexagonal crystal lattice.Lonsdaleite was first identified from the Canyon Diablo meteorite at Barringer Crater (also known as Meteor Crater) in Arizona. It was first discovered in 1967. Lonsdaleite occurs as microscopic crystals associated with diamond in the Canyon Diablo meteorite Kenna meteorite, New Mexico and Allan Hills (ALH) 77283, Victoria Land, Antarctica meteorite. It has also been reported from the Tunguska impact site, Russia. Chaoite Main article Chaoite Chaoite is a mineral believed to have been formed in meteorite impacts.It has been described as slightly harder than graphite with a reflection colour of colorise to white. However, the existence of carbyne phases is disputed see the entry on chaoite for details. Variability of carbon The system of carbon allotropes spans an astounding range ofextremes, considering that they are all besides structural formations ofthe same element. between diamond and graphite * Diamond is hardest mineral known to man (10 on Mohs scale), but graphite is one of the softest (1 2 on Mohs scale). * Diamond is the ultimate abrasive, but graphite is a very good lubricant. Diamond is an excellent electrical insulator, but graphite is a conductor of electricity. * Diamond is usually trans leaven, but graphite is opaque. * Diamond crystallizes in the isometric sy stem but graphite crystallizes in the hexagonal system. Between amorphous carbon and nanotubes * Amorphous carbon is among the easiest materials to synthesize, but carbon nanotubes are extremely expensive to make. * Amorphous carbon is completely isotropic, but carbon nanotubes are among the most anisotropic materials ever produced. ALKENE NAMES expel names give the number of carbons in the longest continuous image.Alkene names are formed by dropping the ane and replacing it with eneThe following list gives samplesExample root = propane drop ane = prop alkene = prop + alkene ending = ene = propene No. of Carbons Root Name Formula CnH2n Structure 2 ethene C2H4 CH2=CH2 3 propene C3H6 CH2=CHCH3 4 1-butene C4H8 CH2=CHCH2CH3 5 1-pentene C5H10 CH2=CHCH2CH2CH3 Following is a list of alkane seriess cover their chemical formulas, their names, the number of isomers, and the melting and the boiling point. Please note that, except for the first four alkanes (n=1.. ), their chemical names can be derived from the number of C atoms by using Greek numerical prefixes denoting the number of carbons and the suffix -ane. Formula Name(s) No. of Isomers m. p. C b. p. C CH4 methane (natural gas) 1 -183 -162 C2H6 ethane 1 -172 -89 C3H8 propane dimethyl methane 1 -188 -42 C4H10 n-butane methylethyl methane 2 -138 0 C5H12 n-pentane 3 -130 36 C6H14 n-hexane 5 -95 69 C7H16 n-heptane 9 -91 98 C8H18 n-octane 18 -57 126 C9H20 n-nonane 35 -54 151 C10H22 n-decane 75 -30 174The simplest organic compounds are hydrocarbons. Hydrocarbons contain only two elements, hydrogen and carbon. A saturated hydrocarbon or alkane is a hydrocarbon in which all of the carbon-carbon bonds are single bonds. Each carbon atom forms four bonds and each hydrogen forms a single bond to a carbon. The bonding around each carbon atom is tetrahedral, so all bond angles are 109. 5. As a result, the carbon atoms in higher alkanes are arranged in zig-zag rather than running(a) patterns. Straight Chain Alkanes The ge neral formula for an alkane is CnH2n+2 where n is the number of carbon atoms in the molecule.There are two ways of opus a condensed structural formula. For example, butane may be written as CH3CH2CH2CH3 or CH3(CH2)2CH3. Rules for Naming Alkanes * The parent name of the molecule is determined by the number of carbons in the longest range. * In the case where two chains have the same number of carbons, the parent is the chain with the most substituents. * The carbons in the chain are numbered starting from the end nearest the first substituent. * In the case where there are substituents having the same number of carbons from both ends, numbering starts from the end nearest the next substituent. When more than one of a given substituent is present, a prefix is applied to indicate the number of substituents. Use di- for two, tri- for three, tetra- for four, etc. and use the number assigned to the carbon to indicate the position of each substituent. branch Alkanes * Branched substitue nts are numbered starting from the carbon of the substituent given over to the parent chain. From this carbon, count the number of carbons in the longest chain of the substituent. The substituent is named as an alkyl group based on the number of carbons in this chain. Numbering of the substituent chain starts from the carbon attached to the parent chain. * The entire name of the branched substituent is placed in parentheses, preceded by a number indicating which parent-chain carbon it joins. * Substituents are listed in alphabetical order. To alphabetize, push aside numerical (di-, tri-, tetra-) prefixes (e. g. , ethyl would come before dimethyl), but dont ignore dont ignore positional prefixes such as iso and tert (e. g. , triethyl comes before tertbutyl). Cyclic Alkanes * The parent name is determined by the number of carbons in the largest ring (e. g. , cycloalkane such as cyclohexane). In the case where the ring is attached to a chain containing additional carbons, the ring i s considered to be a substituent on the chain. A substituted ring that is a substituent on something else is named using the rules for branched alkanes. * When two rings are attached to each other, the larger ring is the parent and the smaller is a cycloalkyl substituent. * The carbons of the ring are numbered such that the substituents are given the lowest possible numbers. Straight Chain Alkanes Carbon Name Molecular Formula morphological Formula 1 Methane CH4 CH4 2 Ethane C2H6 CH3CH3 Propane C3H8 CH3CH2CH3 4 Butane C4H10 CH3CH2CH2CH3 5 Pentane C5H12 CH3CH2CH2CH2CH3 6 Hexane C6H14 CH3(CH2)4CH3 7 Heptane C7H16 CH3(CH2)5CH3 8 Octane C8H18 CH3(CH2)6CH3 9 Nonane C9H20 CH3(CH2)7CH3 10 Decane C10H22 CH3(CH2)8CH3 Alkenes contain carbon-carbon doubling bonds. They are also called unsaturated hydrocarbons. The molecular formular is CnH2n. This is the same molecular formula as a cycloalkane. Structure of Alkenes 1. The two carbon atoms of a parlay bond and the four atoms attached to them lie in a plane, with bond angles of approximately 120 . A mental image bond consists of one sigma bond formed by overlap of sp2 hybrid orbitals and one pi bond formed by overlap of parallel 2 P orbitals Here is a chart containing the systemic name for the first twenty straight chain alkenes. Name Molecular formula Ethene C2H4 Propene C3H6 butene C4H8 Pentene C5H10 Hexene C6H12 Heptene C7H14 Octene C8H16 Nonene C9H18 Decene C10H20 Undecene C11H22 Dodecene C12H24 Tridecene C13H26 Tetradecene C14H28 Pentadecene C15H30 Hexadecene C16H32 Heptadecene C17H34 Octadecene C18H36 Nonadecene C19H38Eicosene C20H40 Did you notice how there is no methene? Because it is impossible for a Carbon to have a double bond with nothing. The Basic Rules A. For straight chain alkenes, it is the same basic rules as nomenclature of alkanes except change the suffix to -ene. i. scram the Longest Carbon Chain that Contains the Carbon Carbon double bond. (If you have t wo ties for longest Carbon chain, and both chains contain a Carbon Carbon double bond, then look for most substituted chain. ) ii. ordain the lowest possible number to the Carbon Carbon double bond. 1.Do not need to number cycloalkenes because it is understood that the double bond is in the one position. 2. Alkenes that have the same molecular formula but the location of the doble bonds are different means they are constitutional isomers. 3. Functional Groups with higher priority iii. Add substituents and their position to the alkene as prefixes. Of course remember to give the lowest numbers possible. And remember to name them in alphabetical order when writting them. iv. Next is identifying stereoisomers. when there are only two non hydrogen attachments to the alkene then use cis and trans to name the molecule.In this diagram this is a cis conformation. It has both the substituents going upward. (This molecule would be called (cis) 5-chloro-3-heptene. ) Trans would look like this v. On the other hand if there are 3 or 4 non-hydrogen different atoms attached to the alkene then use the E, Z system. E (entgegen) means the higher priority groups are opposite one another relative to the double bond. Z (zusammen) means the higher priority groups are on the same side relative to the double bond. (You could think of Z as Zame Zide to help memorize it. ) In this example it is E-4-chloro-3-heptene.It is E because the Chlorine and the CH2CH3 are the two higher priorities and they are on opposite sides. vi. A hydroxyl group gets precedence over th double bond. Therefore alkenes containing alchol groups are called alkenols. And the prefix becomes enol. And this means that now the alcohol gets lowest priority over the alkene. vii. eventually remember that alkene substituents are called alkenyl. Suffix enyl. B. For common names i. mop up the -ane suffix and add -ylene. There are a couple of unique ones like ethenyls common name is vinyl and 2-propenyls common name is all yl.