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Organic Nomenclature and Simple Reactions

  1. Nov 30, 2005 #1
    Hello. Can someone please check my work and help me with these problems. I'm sorry it is so long.

    Predict and balance the following organic equation.

    --------------------------------------------------------

    1. Ethanol (ethyl alcohol) is burned completely in air

    C2H5OH + 3O2 > 2CO2 + 3H2O
    --------------------------------------------------------

    2. Propane gas is heated with chlorine gas

    C3H8 + Cl2 > C3H7Cl + HCl

    --------------------------------------------------------

    3. Ethanol (ethyl alcohol) and methanoic acid (formic acid) are mixed and warmed

    C2H5OH + CH3OH > CO2 + H2O
    If this is correct then how do I balance it?
    --------------------------------------------------------

    4. Ethene gas is bubbled through a solution of bromine

    C2H4 + Br2 > C2H4Br2
    --------------------------------------------------------

    5. Hydrogen gas is added to 2-pentene

    H2 + C5H10 > C5H12
    --------------------------------------------------------

    6. Octane is burned in oxygen

    2C8H18 + 25 O2 > 16CO2 + 18H2O
    --------------------------------------------------------

    7. 2-butene is combined with hydrogen gas in the presence of a nickel catalyst

    C4H10 + H2 +Ni > ???

    --------------------------------------------------------

    8. Ethanoic acid is combined with propanol

    C2H5OH + C3H7OH > CO2 + H2O
    If this is correct then how do I balance it?
    --------------------------------------------------------

    9. An excess of chlorine gas is added to pure ethyne (acetylene) gas

    Cl2 + C2H2 > C2H2Cl2
    --------------------------------------------------------

    10. A limited amount of liquid bromine is added to an excess of benzene (C6H6)

    Br2 + C6H6 > C6H4Br2 + H2
    --------------------------------------------------------
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

    Name the following hydrocarbon compounds.

    1. (CH3)2CHCl

    dimethyl?? How do I name it with the Cl ??
    --------------------------------------------------------

    2. CH3C(CH3)2CH2C(CH3)2CH2CH2CH3

    2,4 dimethylheptane
    --------------------------------------------------------

    3. CH3C(CH3)2CH - - C(CH3)CH2CH3

    2,4 dimethylpentane
    --------------------------------------------------------

    4. CH3C --- CCH3

    1,2 dimethylethane
    --------------------------------------------------------

    Thanks
     
  2. jcsd
  3. Dec 4, 2005 #2

    siddharth

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    That's right.
    There can be more than 1 product here. This looks like the halogenation reaction. You will have to carry this out in the presence of sunlight
    --------------------------------------------------------
    No, this is not correct. Formic acid is HCOOH. CH3OH is methanol
    --------------------------------------------------------
    This is correct.

    --------------------------------------------------------
    Will there be a reaction? I think you would require a presence of a catalyst to notice any reaction.
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    Products are right. I have not checked if it's balanced
    --------------------------------------------------------
    Refer question 5

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    This is wrong. Ethanoic acid is CH3COOH. C2H5OH is Ethanol.
    --------------------------------------------------------
    Not completly correct.
    You are adding an excess of Chlorine gas. Will the reaction stop here?

    --------------------------------------------------------
    This is wrong. Benzene is aromatic. It will undergo substitution reactions rather than addition reactions.


    The longest Carbon chain is 3 carbons long. So it will be a substitited propane rather than dimethyl methane. I'll do this one and see if you can do the rest. The IUPAC name will be 2-Chloro Propane.
    --------------------------------------------------------
    This is not correct. How many methyl groups are attached? 2 on the second carbon and 2 on the fourth carbon.
    --------------------------------------------------------
    This is wrong.
    Look at the longest Carbon chain. Besides, there is a double bond. So it should be an alkene
    --------------------------------------------------------
    There should be a triple bond right? So it's an alkyne not an alkane.
     
    Last edited: Dec 4, 2005
  4. Dec 4, 2005 #3

    GCT

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    if it's an aqueous solution you'll need to reconsider

    for number 9, you might also want to consider this

    http://jchemed.chem.wisc.edu/JCESoft/CCA/CCA3/MAIN/CLACET/PAGE1.HTM
     
  5. Dec 5, 2005 #4

    siddharth

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  6. Dec 8, 2005 #5

    GCT

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    well I remembered that alkynes don't undergo electrophilic additions as well as the alkenes, the exact reason I do not recall at the moment. There are methods of addition (whether electrophilic or nucleophilic) but I remember that it involves some sort of metal catalyst. There are some important reactions with ethyne (such as the possibility of carbon carbon bond formation) but I wasn't familiar with it just reacting with a bromine molecule (I can't remember at the moment but a particular halogenated ethane or ethene isomer predominates between interconversions of isomers and is a byproduct of a laundry detergent or some other industrial chemical....that is before they stopped using it-that is tetra-chloroethane may be formed to a certain extent).
     
  7. Dec 10, 2005 #6

    siddharth

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    When I learnt this a couple of years ago in high school, I was taught that the addition of halogens to alkenes and alkynes is by the halonium ion intermediate (ie, the cyclic intermediate with the Br+ and the 2 carbons).

    That is, in the first step the attacking species is Br+ which forms this cyclic halonium. Then, in the second step the Br- reacts with the halide ion to give the addition product.

    So, I guess the reason why alkynes don't undergo electrophilic addition with halogens as well as alkenes is beacuse the intermediate formed with the alkynes is more strained and less stable than the intermediate formed from the alkenes.

    In all my exams to date, I have been writing that the final product when excess halogens react with alkynes is the tetrahalo alkane. It was a suprise when you showed that it wasn't true for ethyne
     
    Last edited: Dec 10, 2005
  8. Nov 6, 2006 #7
    Hey
    i noticed you has the reaction for Propane + chloride = C3H7Cl + Hydrochloric acid

    what is the name of C3H7Cl using the IUPAC system for naming
     
  9. Nov 6, 2006 #8
    I belive you would refer to that one as either 1 or 2- chloro-propane depending upon the substitution location.
     
  10. Mar 25, 2007 #9
    hey, thanks for the anwers

    #3 should be C2H5OH plus CHOOH yield C2H5OOCH plus H2O, i think. Also, (CH3)2CHCl is 1-chloro-1-dimethylmethane. I'm not sure if you need the 1 though.
     
  11. Mar 26, 2007 #10

    chemisttree

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    This is possible if acetylene is introduced into a chlorine atmosphere in an uncontrolled (thermally) manner. The reaction is exothermic enought to decompose the initially-formed dichloroethene to carbon black. Under controlled conditions, the dichloro or tetrachloro product can form. Addition of X2 across the triple and double bonds is achieved under lower temperature conditions by performing the reaction under dilution with cooling and with metal catalysts (copper, manganese, etc...).
     
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