Structural formulas for alkanes

Assign lUPAC names and draw structural formulas for alkanes. (Section 1.7)... 

Assign lUPAC names and draw structural formulas for alkanes. 

We can write structural formulas for alkanes in still another abbreviated form. The structural formula of pentane, for example, contains three CHg (methylene) groups in the middle of the chain. We can collect these groups together and write the structural formula as CH3(CH2)sCH3. Table 3.1 gives the names and molecular formulas of the first 20 alkanes. Note that the names of all these alkanes end in -ane. We will have more to say about naming alkanes in Section 3.3. 

Isobutane has the same molecular formula, C4HJ0, as w-butane, but a different structure. Molecules having the same molecular formula but different structures are called isomers. Isomers have different properties from each other and can be distinguished by inspecting their structural formulas. For alkanes, the number of possible isomers increases with the number of carbon atoms in the alkane. Pentane has 3 isomers, hexane has 5, octane has 18, and an alkane with 20 carbon atoms has 356,319. 

Drawing Expanded and Condensed Structural Formulas for Alkanes... 

The smaller alkanes from 1-4 carbon atoms are gases at room temperature and used as heating fuels. The alkanes with 5-8 carbon atoms are liquids at room temperature and found in fuels such as gasoline. The molecular formula gives the total number of each kind of atom, but does not indicate the arrangement of the atoms in the molecule. Table 17.2 shows the molecular, expanded, and condensed structural formulas for alkanes with one, two, and three carbon atoms. 

LEARHINB GOAL Write the IUPAC names and draw the condensed structural formulas for alkanes with substituents. 

Draw the condensed structural formula for alkanes or the skeletal formula for cycloalkanes for each of the following ... 

An n alkane of molecular formula C28H58 has been isolated from a certain fossil plant Write a condensed structural formula for this alkane J... 

In Problem 2 5 you were asked to write structural formulas for the five isomeric alkanes of molecular formula C6H14 In the next section you will see how the lUPAC rules generate a unique name for each isomer... 

Phytane is a naturally occurring alkane produced by the alga Spirogyra and is a constituent of petroleum The lUPAC name for phytane is 2 6 10 14 tetramethylhexadecane Write a structural formula for phytane... 

Draw two-dimensional structural formulas for all the isomeric alkanes of formula C5H12. 

Self-Test 18.4A Write the condensed structural formulas for the five isomeric alkanes of molecular formula C6H14. 

The empirical formula is C4Hy the molecular formula might be C jHlg, which matches the formula for alkanes (C H, +,). It is not likely an alkene or alkyne, because there is no reasonable Lewis structure for a compound having the empirical formula C4II9 and multiple bonds. 

Methane, CH4, has one carbon atom. The next two members of the alkane family are ethane, C2H6, and propane, C3H8. Molecules of these compounds contain chains of two carbon atoms and three carbon atoms, respectively. Alkanes with more than three carbon atoms have more than one isomer. There are two structural formulas for butane, C4H10, and three structural formulas for pentane, C5H12. 

The structural formula for butane shows all the carbons linked in a straight chain. In reality, the carbons actually line up in a zigzag fashion, so the term straight chain simply refers to a continuous arrangement of carbon atoms. Butane and alkanes that... 

Probidin 5.38 Deduce the structural formula for an optically active alkene, C H,2, which reacts with H. to form an optically inactive alkane, C(,H,4. M... 

Consider ethane, the alkane with two carbon atoms and six attached hydrogen atoms. If one of the hydrogen atoms is replaced by an OH group, the result is ethyl alcohol, or ethanol, the alcohol portion of alcoholic beverages. The OH is the alcohol group. The names of alcohols end in -ol. The structural formulas for ethane and ethyl alcohol are ... 

Following are structural formulas for each alkane or cycloalkane ... 

The simplest hydrocarbons, alkanes, have carbon atoms that are connected only by single bonds. Three examples include methane, ethane, and propane. The structural formulas for each of these alkanes are drawn as follows. 

If you examine the structural formulas for these three alkanes, you will notice that each member of the series differs from the one before by one carbon atom and two hydrogen atoms. This difference is more obvious when you compare the molecular formulas of each compound. The molecular formulas of the alkanes fit the general formula C H2 +2, where n represents the number of carbon atoms. If the alkane contains 30 carbon atoms, then its formula is C3oH62-... 

Draw a structural formula for the straight-chain hydrocarbon with the molecular formula C3H6. Is this an alkane, alkene, or alkyne ... 

If you said that all of these structures represent the same compound, you are correct. The diagram simply shows four ways of drawing a structural formula for 2-methylbutane. As you can see, the structural formula for a given hydrocarbon can be written in several ways. Before you continue reading, make sure that you understand why these structural formulas are all alike. You ll soon learn, however, that three distinctly different alkanes have the molecular formula C5H12. 

Write the structural formulas for the following branched alkanes. 

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