Pentanoic acid has 4 carbon atoms with 7 H's bonded to them and 1 carbon atom with a carboxyl ion bonded to it.
In the drawings below, I have left off all the single bonded H's to simplify the drawing.
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Go to this web site to see a carboxylic group or do a Google search for carboxylic group.
http://www.ch.ic.ac.uk/vchemlib/mol/glossary/carboxyl.gif
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A carboxyl ion is a carbon atom with one oxygen atom double bonded to it, and an O-H single bonded to it as shown below. It has a -1 charge as shown by the - mark to the left of the C. The - ark actually represents one unpaired electron desiring to find another atom with one unpaired electron.
…..H
…..!
….O
….!
...-C=O
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Isotope #1
Draw a row of 4 carbon atoms.
Attach a carboxyl ion to the #1 C atom of the 4 you drew.
Now the structure has 5 C atoms in a row.
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…...H
…...!
O=C-C-C-C-C
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Attaching a carboxyl ion to #4 C is the same as attaching a carboxyl ion to the #1 C atom. (depending on what side of the table you are sitting on, right becomes left)
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………….H
……….…!
C-C-C-C=O-H
Isotope #2
Attaching a carboxyl ion to the #2 C atom is the same as attaching a carboxyl ion to the #3 C atom.
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…....H
....….!
....…O
….....!
C-C-C-C
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…….H
…….!
……O
……!
C-C-C-C
Isotope #3
Draw a row of 3 carbon atoms, with 1carbon atom bonded below #2 C atom. Attach the carboxyl ion above the #2 C atom. I see 3 carbon atoms in a horizontal line or 3 carbon atoms in a vertical line. There are 4 carbon atoms attached to a central carbon atom. No matter where I attach the double bond O, single bond H, it is attached to one of these 4 carbon atoms.
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…H
….!
….C=O-H
….!
C-C-C
…!
...C
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There only 3 isotopes
Draw a line of 5 C's
…..2..3..4
-C-C-C-C-C-
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You might wonder why you can not attach a double bond O, single bond H to Carbon atoms #2, #3,or #4. Looking at the carboxyl ion below, how many bonds does the carbon have around it? I see 3 bonds. (double bond O (2), single bond H (1)) A carbon can only make 4 bonds. If you try to attach a carboxyl ion to Carbon atoms #2, #3, or #4, you still need 2 bonds to attach to the Carbon atoms on the left and right side of that carbon.
…..H
…..!
….O
….!
...-C=O
If you can get a molecular model you can build these isotopes and, determine how many different isotopes you can make.
Nonane has a total of 75 isomers, which includes straight chain isomers, branched chain isomers, and cyclic isomers.
There are two isomers for dibromopropane: 1,2-dibromopropane and 2,2-dibromopropane.
None, as it has 5 structural isomers in which none of are optically active.
There are 5 isomers of C6H12C12, namely n-hexane, 2-methylpentane, 3-methylpentane, 2,2-dimethylbutane, and cyclohexane.
The dehydration of cyclohexanol can form two isomers: cyclohexene and cyclohexadiene. These isomers result from different locations of the double bond formed during the dehydration process.
Three
Nonane has a total of 75 isomers, which includes straight chain isomers, branched chain isomers, and cyclic isomers.
Three isomers of C2HfClBr are possible.
C3H4O can have two isomers: propynal and cyclopropanone.
There are two isomers for dibromopropane: 1,2-dibromopropane and 2,2-dibromopropane.
There are a total of three structural isomers of C7H16 that have no secondary hydrogen atoms. These isomers are 2-methylhexane, 3-methylhexane, and 2,2-dimethylpentane.
Three
This compound (dibromomethane) has only one form. It does not form isomers .
None, as it has 5 structural isomers in which none of are optically active.
There are three isomers of C3H6I2: 1,1-diiodopropane, 1,2-diiodopropane, and 2,2-diiodopropane.
There are three isomers that can be constructed for C3H6I2. These include 1,1-diiodopropane, 1,2-diiodopropane, and 2-iodopropane.
There are three isomers of C2H2Br2: 1,1-dibromoethane, 1,2-dibromoethane, and vinyl bromide.