Welcome to the Organic Compounds Database. This 2483 compound database has been compiled by Harold M. Bell at Virginia Tech. Fill in the form below with as much. C hem gu id e – q u e s tio n s NAMING ORGANIC COMPOUNDS: 1 Important: These questions cover all the compounds on this page. If you are doing this sensibly.
Organic Chemistry: Structure and Nomenclature of Hydrocarbons. When you drive up to the pump at some gas stations you are faced with a variety of. You can buy . As you filled the tank, you might wonder, . Once again, you are faced with. ![]() You could buy aspirin, which has been used for almost a. Or Tylenol, which contains acetaminophen. Or a more modern pain- killer. While you are deciding which drug to buy, you might wonder, . While you're eating, a friend stops. For more than 2. 00 years, chemists have divided materials into two. Those isolated from plants and animals were classified as organic. At one time, chemists. The first step in the decline of the vital force theory occurred in 1. Friederich Wohler synthesized urea from inorganic starting materials. Wohler was trying to. NH4. OCN) from silver cyanate (Ag. OCN) and ammonium. ![]() NH4. Cl). What he expected is described by the following equation. Ag. OCN(aq) + NH4. Cl(aq) Ag. Cl(s) + NH4. OCN(aq). The product he isolated from this reaction had none of the properties of cyanate. It was a white, crystalline material that was identical to urea, H2. NCONH2. which could be isolated from urine. Neither Wohler nor his contemporaries claimed that his results disproved the vital. But his results set in motion a series of experiments that led to the. This. inevitably led to the disappearance of . If the difference between organic and inorganic compounds isn't the presence of some. Most compounds extracted from living organisms contain. It is therefore tempting to identify organic chemistry as the chemistry of carbon. Even though organic chemistry focuses on compounds that contain carbon and hydrogen. The special role of carbon in the chemistry of the elements is. The Physical Properties of Carbon Electronic configuration 1s. Electronegativity 2. Covalent radius 0. Carbon has four valence electrons 2s. The. electronegativity of carbon is too small for carbon to gain electrons from most elements. C4- ions, and too large for carbon to lose electrons to form C4+. Carbon therefore forms covalent bonds with a large number of other elements. Because they are relatively small, carbon atoms can come close enough together to form. C=C double bonds or even CC. Carbon also forms strong double and triple bonds to nitrogen and oxygen. It. can even form double bonds to elements such as phosphorus or sulfur that do not form. Several years ago, the unmanned Viking spacecraft carried out experiments designed to. Mars. These experiments were based on the assumption that. Several factors make carbon. No other element can provide the variety of combinations and permutations necessary for. Compounds that contain only carbon and hydrogen are known as hydrocarbons. The simplest alkane is methane: CH4. The Lewis structure of methane can be. Methane is an example of a general rule that carbon is tetravalent; it. To minimize the repulsion. CH. bonds, the geometry around the carbon atom is tetrahedral, as shown in the figure below. The alkane that contains three carbon atoms is known as propane, which has the formula. C3. H8 and the following skeleton structure. The four- carbon alkane is butane, with the formula C4. H1. 0. The names, formulas, and physical properties for a variety of alkanes with the generic. Cn. H2n+2 are given in the table below. The. boiling points of the alkanes gradually increase with the molecular weight of these. At room temperature, the lighter alkanes are gases; the midweight alkanes are. The Saturated Hydrocarbons, or Alkanes Name. Molecular. Formula. Melting. Point (o. C)Boiling. Point (o. C)Stateat 2. 5o. Cmethane CH4- 1. C2. H6- 1. 83. 3 - 8. C3. H8- 1. 89. 7 - 4. C4. H1. 0- 1. 38. C5. H1. 2- 1. 29. C6. H1. 4- 9. 56. C7. H1. 6- 9. 0. 6 9. C8. H1. 8- 5. 6. 8 1. C9. H2. 0- 5. 1 1. C1. 0H2. 2- 2. 9. C1. 1H2. 4- 2. 4. C1. 2H2. 6- 9. 6. C2. 0H4. 23. 6. 8 3. C3. 0H6. 26. 5. 8. The alkanes in the table above are all straight- chain hydrocarbons, in. Thus, for every n carbon atoms there must be 2n + 2 hydrogen. Cn. H2n+2. Because two points define a line, the carbon skeleton of the ethane molecule is linear. Because the bond angle in a tetrahedron is 1. The smallest hydrocarbon in which a branch can occur has four carbon atoms. Compounds with the same formula and different structures are known as. Greek isos, . When it was first discovered, the branched isomer with the formula C4. H1. 0. was therefore given the name isobutane. Isobutane. The best way to understand the difference between the structures of butane and. Butane and isobutane are called constitutional isomers because they. One contains two CH3 groups and two CH2. CH3 groups and one CH group. There are three constitutional isomers of pentane, C5. H1. 2. The. first is . A branched isomer is also possible, which was originally named isopentane. When a more. highly branched isomer was discovered, it was named neopentane (the new isomer of. Ball- and- stick models of the three isomers of pentane are shown in the figure below. There are two constitutional isomers with the formula C4. H1. 0. three isomers of C5. H1. 2, and five isomers of C6. H1. 4. There. are over 4 billion isomers for C3. H6. 2, for example. If the carbon chain that forms the backbone of a straight- chain hydrocarbon is long. Cycloalkanes. therefore have two less hydrogen atoms than the parent alkane and a generic formula of Cn. H2n. The angle between adjacent CC bonds is only 6. Cyclopropane is therefore susceptible to chemical reactions that can open up the. Any attempt to force the four carbons that form a cyclobutane ring into a plane of. CC bonds would be 9. One of the four carbon atoms in the cyclobutane ring is therefore displaced from the. The angle between adjacent CC bonds in. Cyclopentane is not a planar molecule, as shown in the figure. By the time we get to the six- membered ring in cyclohexane, a puckered structure can be. One of these carbon atoms is tilted up, out of the. As one looks at the structure of the ethane molecule, it is easy to fall into the trap. Nothing could be further from the. At room temperature, the average velocity of an ethane molecule is about 5. Boeing 7. 47. At the same time, the CH and CC bonds are vibrating. There is another way in which the ethane molecule can move. The CH3 groups. at either end of the molecule can rotate with respect to each around the CC bond. When this happens, the molecule passes. The highest energy conformation corresponds to a structure in which the hydrogen. The lowest energy conformation is a structure in which the hydrogen atoms are. The difference between the eclipsed and staggered conformations of ethane are best. CC bond, as shown in the figure below. The difference between the energies of these conformations is relatively. J/mol. But it is large enough that rotation around the CC bond is not smooth. Although the frequency. The different conformations of a molecule are often described in terms of Newman. These line drawings show the six substituents on the CC bond as if the structure of the molecule was. CC bond in a ball- and- stick model of the. Newman projections for the different staggered conformations of butane are shown. Because of the ease of rotation around CC bonds, there are several conformations of some of the cycloalkanes. Cyclohexane, for example, forms both the. The difference between the energies of the chair conformation, in which the hydrogen. J/mol. As a result, even though the rate at which these two conformations interchange is. Common names such as pentane, isopentane, and neopentane are sufficient to. C5. H1. 2. They. become less useful, however, as the size of the hydrocarbon chain increases. The International Union of Pure and Applied Chemistry (IUPAC) has developed a. Name the. compound as a derivative of the alkane with this number of carbon atoms. The following. compound, for example, is a derivative of pentane because the longest chain contains five. Name the substituents on the chain. Substituents derived from alkanes are named by. This compound contains a methyl (CH3- ). Number the chain starting at the end nearest the first substituent and specify the. Use the lowest possible numbers. This. compound, for example, is 2- methylpentane, not 4- methylpentane. Use the prefixes di- , tri- , and tetra- to describe. Arrange the names of the substituents in alphabetical order. Carbon not only forms the strong CC. C=C double bonds. Compounds that. contain C=C double bonds were once known as olefins (literally, . The simplest alkene has. C2. H4 and the following Lewis structure. The relationship between alkanes and alkenes can be understood by. We start by breaking the bond in an H2. We do the same. thing to one of the bonds between the carbon atoms in an alkene. We then allow the. CH bond. Thus, in theory, we can transform an alkene into the parent alkane by adding an H2. C=C double bond. In practice, this reaction only occurs at high. Because an alkene can be thought of as a derivative of an alkane from which an H2. C=C double bond is Cn. H2n. They were once named by adding the. The IUPAC nomenclature for alkenes names these compounds as derivatives of the parent. The presence of the C=C double bond is indicated by changing the - ane. The location of the C=C double bond in the skeleton structure of the compound is. C=C bond starts. The names of substituents are then added as prefixes to the name of the alkene. Compounds that contain CC triple bonds are called alkynes. These compounds have four. Cn. H2n- 2. The simplest alkyne has the formula C2. H2. and is known by the common name acetylene. The IUPAC nomenclature for alkynes names these compounds as derivatives of the parent. In addition to compounds that contain one double bond (alkenes) or one triple. Organic Chemistry: Structure and Nomenclature of Hydrocarbons. Structure and Nomenclature of.
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