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Acetic acid, CH 3 CO 2 H, constitutes 3–6% vinegar. Cider vinegar is produced by allowing apple juice to ferment without oxygen present. Yeast cells present in the juice carry out the fermentation reactions. The fermentation reactions change the sugar present in the juice to ethanol, then to acetic acid. Pure acetic acid has a penetrating odor and produces painful burns. It is an excellent solvent for many organic and some inorganic compounds, and it is essential in the production of cellulose acetate, a component of many synthetic fibers such as rayon.

The distinctive and attractive odors and flavors of many flowers, perfumes, and ripe fruits are due to the presence of one or more esters ( [link] ). Among the most important of the natural esters are fats (such as lard, tallow, and butter) and oils (such as linseed, cottonseed, and olive oils), which are esters of the trihydroxyl alcohol glycerine, C 3 H 5 (OH) 3 , with large carboxylic acids, such as palmitic acid, CH 3 (CH 2 ) 14 CO 2 H, stearic acid, CH 3 (CH 2 ) 16 CO 2 H, and oleic acid, CH 3 ( C H 2 ) 7 CH = CH ( CH 2 ) 7 C O 2 H. Oleic acid is an unsaturated acid; it contains a C = C double bond. Palmitic and stearic acids are saturated acids that contain no double or triple bonds.

This is a photo of a bright red strawberry being held in a human hand.
Over 350 different volatile molecules (many members of the ester family) have been identified in strawberries. (credit: Rebecca Siegel)

Key concepts and summary

Functional groups related to the carbonyl group include the –CHO group of an aldehyde, the –CO– group of a ketone, the –CO 2 H group of a carboxylic acid, and the –CO 2 R group of an ester. The carbonyl group, a carbon-oxygen double bond, is the key structure in these classes of organic molecules: Aldehydes contain at least one hydrogen atom attached to the carbonyl carbon atom, ketones contain two carbon groups attached to the carbonyl carbon atom, carboxylic acids contain a hydroxyl group attached to the carbonyl carbon atom, and esters contain an oxygen atom attached to another carbon group connected to the carbonyl carbon atom. All of these compounds contain oxidized carbon atoms relative to the carbon atom of an alcohol group.

Chemistry end of chapter exercises

Order the following molecules from least to most oxidized, based on the marked carbon atom:
Structure a shows a C H subscript 3 group bonded up and to the right to a C H group which is bonded down and to the left to a C H subscript 3 group. Above the C H group is bonded an O H group. The C in the C H group is red. Structure b shows a C H subscript 3 group bonded up and to the right to a C H subscript 2 group which is bonded down and to the right to a C H subscript 3 group. The C in the C H subscript 2 group is red. Structure c shows a C H subscript 3 group bonded up and to the right to a red C atom. This C atom forms a double bond with an O atom above it. The C atom also forms a bond with a C H subscript 3 group down and to the right.

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Predict the products of oxidizing the molecules shown in this problem. In each case, identify the product that will result from the minimal increase in oxidation state for the highlighted carbon atom:

(a)
The left side of a reaction and arrow are shown. The arrow is labeled with an O in brackets. To the left of the arrow is a molecular structure. It shows a C H subscript 3 group which bonds up and to the right to a C H subscript 2 group. The C H subscript 2 group forms a bond down and to the left to a C atom. This C atom appears in red and forms a double bond with an O atom and a single bond with an H atom.

(b)
The left side of a reaction and arrow are shown. The arrow is labeled with an O in brackets. To the left of the arrow is a molecular structure. It shows a C H subscript 3 group bonded up and to the right to a C H subscript 2 group bonded down and to the right to a C H subscript 2 group which is bonded up and to the right to an O H group. The C in the second C H subscript 2 group is red.

(c)
The left side of a reaction and arrow are shown. The arrow is labeled with an O in brackets. To the left of the arrow is a molecular structure. It shows a C H subscript 3 group bonded up and to the right to a C H subscript 2 group which is bonded down and to the right to a C H group. The C in this C H group appears in red. The C in the C H group is bonded directly below it to a C H subscript 3 group. The C H group is bonded up and to the right to an O H group.

(a)
A molecular structure is shown with a C H subscript 3 group bonded up and to the right to a C H subscript 2 group which is bonded down and to the left to a C atom. This C atom appears in red. The C atom forms a double bond with an O atom up and to the right. The C atom also forms a single bond with an O H group directly below it. ;
(b)
A molecular structure is shown with a C H subscript 3 group bonded up and to the right to a C H subscript 2 group which is bonded down and to the left to a C group. This C atom appears in red. The C atom forms a double bond with an O atom up and to the right. Directly below the C atom is a single bond to an H atom. ;
(c)
A molecular structure is shown with a C H subscript 3 group which is bonded up and to the right to a C H subscript 2 group. The C H subscript 2 group is bonded down and to the left to an C atom. This C atom appears in red. The C atom forms a double bond with an O atom up and to the right. The C atom also forms a single bond to a C H subscript 3 group which appears directly below it.

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Predict the products of reducing the following molecules. In each case, identify the product that will result from the minimal decrease in oxidation state for the highlighted carbon atom:

(a)
The left side of a reaction and arrow are shown. The arrow is labeled with an R in brackets. To the left of the arrow is a molecular structure that shows a central, red C atom. This C atom is bonded to a C H subscript 3 group, and H atom, and an O atom. It forms a double bond with the O atom.

(b)
The left side of a reaction and arrow are shown. The arrow is labeled with an R in brackets. To the left of the arrow is a molecular structure that shows a central, red C atom. This C atom is bonded to 2 C H subscript 3 groups, and it forms a double bond with an O atom.

(c)
The left side of a reaction and arrow are shown. The arrow is labeled with an R in brackets. To the left of the arrow is a molecular structure which shows a central, red C atom which is bonded to a C H subscript 3 group, and O H group, and forms a double bond with an O atom.

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Explain why it is not possible to prepare a ketone that contains only two carbon atoms.

A ketone contains a group bonded to two additional carbon atoms; thus, a minimum of three carbon atoms are needed.

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How does hybridization of the substituted carbon atom change when an alcohol is converted into an aldehyde? An aldehyde to a carboxylic acid?

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Fatty acids are carboxylic acids that have long hydrocarbon chains attached to a carboxylate group. How does a saturated fatty acid differ from an unsaturated fatty acid? How are they similar?

Since they are both carboxylic acids, they each contain the –COOH functional group and its characteristics. The difference is the hydrocarbon chain in a saturated fatty acid contains no double or triple bonds, whereas the hydrocarbon chain in an unsaturated fatty acid contains one or more multiple bonds.

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Write a condensed structural formula, such as CH 3 CH 3 , and describe the molecular geometry at each carbon atom.

(a) propene

(b) 1-butanol

(c) ethyl propyl ether

(d) cis -4-bromo-2-heptene

(e) 2,2,3-trimethylhexane

(f) formaldehyde

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Write a condensed structural formula, such as CH 3 CH 3 , and describe the molecular geometry at each carbon atom.

(a) 2-propanol

(b) acetone

(c) dimethyl ether

(d) acetic acid

(e) 3-methyl-1-hexene

(a) CH 3 CH(OH)CH 3 : all carbons are tetrahedral; (b) CH 3 C O CH 3 : the end carbons are tetrahedral and the central carbon is trigonal planar; (c) CH 3 OCH 3 : all are tetrahedral; (d) CH 3 COOH: the methyl carbon is tetrahedral and the acid carbon is trigonal planar; (e) CH 3 CH 2 CH 2 CH(CH 3 )CHCH 2 : all are tetrahedral except the right-most two carbons, which are trigonal planar

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The foul odor of rancid butter is caused by butyric acid, CH 3 CH 2 CH 2 CO 2 H.

(a) Draw the Lewis structure and determine the oxidation number and hybridization for each carbon atom in the molecule.

(b) The esters formed from butyric acid are pleasant-smelling compounds found in fruits and used in perfumes. Draw the Lewis structure for the ester formed from the reaction of butyric acid with 2-propanol.

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Write the two-resonance structures for the acetate ion.

A structure shows in brackets a C atom with H atoms bonded above, below, and to the left, and a C atom bonded to the right. This second C atom has an O atom double bonded above and to the right and a second O atom single bonded below and to the right. Outside the brackets to the right appears a superscript minus sign. This is followed by a double headed arrow. To the right of this arrow in brackets is a C atom with H atoms bonded above, below, and to the left, and a C atom bonded to the right. This second C atom has an O atom single bonded above and to the right and a second O atom double bonded below and to the right. Outside the brackets to the right appears a superscript minus symbol. Double bonded O atoms have two pairs of electron dots and single bonded O atoms have 3 pairs of electron dots.
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Write two complete, balanced equations for each of the following reactions, one using condensed formulas and one using Lewis structures:

(a) ethanol reacts with propionic acid

(b) benzoic acid, C 6 H 5 CO 2 H, is added to a solution of sodium hydroxide

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Write two complete balanced equations for each of the following reactions, one using condensed formulas and one using Lewis structures.

(a) 1-butanol reacts with acetic acid

(b) propionic acid is poured onto solid calcium carbonate

(a) CH 3 CH 2 CH 2 CH 2 OH + CH 3 C ( O ) OH CH 3 C ( O ) OCH 2 CH 2 CH 2 CH 3 + H 2 O:
A reaction is shown. The first molecular structure shows a C atom bonded to three H atoms and another C atom. This second C atom is bonded to two H atoms and a third C atom. This third C atom is bonded to two H atoms and a fourth C atom. This C atom is bonded to two H atoms and an O atom. The O atom is bonded to an H atom. The O atom has two pairs of electrons dots. There is a plus sign. The next molecular structure shows a C atom bonded to three H atoms and another C atom. This C atom forms a double bond with an O atom and a single bond with another O atom. The O atom forms a bond with an H atom. Both O atoms have two pairs of electron dots. There is a reaction arrow that points right. The next molecular structure shows a C atom bonded to three H atoms and another C atom. This second C atom forms a double bond with an O atom and a single bond with another O atom. This second O atom is bonded to a C atom which is bonded to two H atoms and another C atom. This C atom is bonded to two H atoms and another C. This C atom is bonded to two H atoms and another C atom. The C atom is bonded to three H atoms. The O atoms have two pairs of electron dots. There is a plus sign. The final molecular structure shows an O atom bonded to two H atoms. The O atom has two pairs of electron dots. ;
(b) 2 CH 3 CH 2 COOH + CaCO 3 ( CH 3 CH 2 COO ) 2 Ca + CO 2 + H 2 O:
A reaction is shown. There is a 2 in front of the first molecular structure. This first structure shows a C atom bonded to three H atoms and another C atom. This second C atom is bonded to two H atoms and a third C atom. This third C atom forms a double bond with an O atom and a single bond with another O atom. This second O atom forms a single bond with an H atom. Both O atoms have two pairs of electron dots. There is a plus sign and C a superscript 2 plus sign. Beside the C a superscript 2 plus sign is a set of brackets. Inside the brackets is a central C atom bonded to three O atoms. Two O atoms have three pairs of electron dots, and one O atom has two pairs of electron dots. A 2 minus sign appears as a superscript to the brackets. There is an arrow pointing right. There is a 2 and a set of brackets. Inside the brackets is a C atom bonded to three H atoms and another C atom. This C atom is bonded to two H atoms and a third C atom. This C atom is bonded to two O atoms. One O atom has two pairs of electron dots, and one O atom has three pairs of electron dots. Outside the brackets a minus sign appears as a superscript. C a superscript 2+ also appears beside the brackets. There is a plus sign. The next molecular structure shows a C atom that forms two sets of double bonds with two O atoms. Each O atom has two pairs of electron dots. There is a plus sign. The final molecular structure shows an O atom bonded to two H atoms. The O atom has two pairs of electron dots.

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Yields in organic reactions are sometimes low. What is the percent yield of a process that produces 13.0 g of ethyl acetate from 10.0 g of CH 3 CO 2 H?

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Alcohols A, B, and C all have the composition C 4 H 10 O. Molecules of alcohol A contain a branched carbon chain and can be oxidized to an aldehyde; molecules of alcohol B contain a linear carbon chain and can be oxidized to a ketone; and molecules of alcohol C can be oxidized to neither an aldehyde nor a ketone. Write the Lewis structures of these molecules.

This figure shows three molecular structures labeled compound A, compound B, and compound C. In A, a C atom is shown bonded the three H atoms and a second C atom. This C atom is bonded to one H atom. Up and to the right it is bonded to another C atom which is bonded to three H atoms. Down and to the left it is bonded to another C atom which is bonded to two H atoms and an O atom. The O atom is bonded to an H atom. The O atom has two pairs of electron dots. In B, a C atom is bonded to three H atoms and another C atom. This second C atom is bonded to an H atom and an O atom. The O atom has two pairs of electron dots and is bonded to an H atom. The second C atom is bonded to third C atom which is bonded to two H atoms. The third C atom is bonded to a fourth C atom which is bonded to three H atoms. In C, a C atom is bonded to three H atoms and another C atom. This C atom is bonded above to another C atom which is bonded to three H atoms, and below to a C atom which is bonded to three H atoms. It is also bonded to an O atom which is bonded to an H atom. The O atom has two pairs of electron dots.
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Questions & Answers

what is the periodic table all about
Godstime Reply
am new here looking forward on learning new stuff
Godstime
answer me please
Godstime
yeah
samuel
it's about predicting the different types of matter around us and organizing them in an elegant way
William
what is boyle law
Daniel Reply
the law states that at a constant absolute temperature the volume of a fixed of a gas is inversely proportional to the pressure of the gas...
Johnson
write short not on paper chromAtogphy
Ujunwa Reply
I am sorry, I don't understand the question. Are you referring to photospectometry, a machine that uses lightwaves to determine the chemical composition of a substance? Instead of the "coffee filter and solvent" method which is more crude, but simple enough to understand basic concepts.
Melissa
kkk
samuel
what is esterification?
Darey Reply
Esterification is the general name for a chemical reaction in which two reactants (typically an alcohol and an acid) form an ester(-COOR) as the reaction product....
Johnson
pls i dont know chemistry wat shall i do?
Chancha
Please...what do you mean by you don't know chemistry..can you explain further
Johnson
I am afraid you may end up injuring yourself working with these chemical processes with limited lab experience. Please be extremely careful. Research chem analysis, precedure and equipment.
Melissa
Kkk
samuel
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samuel
how we Learn full periodic table
muhammad Reply
how
Imran
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Angel Reply
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Michael
explain the atomic orbital
Masti Reply
2nacl➡️2na+cl2 2.58.5g 22.4l
suvarthavani Reply
what is neclear energy
Moyosoreoluwa Reply
nuclear energy is the energy released during nuclear fission or fusion.especially when used to generate electricity
Inusah
How many processes to break down CARBON DIOXIDE into carbon and oxygen
Prabhakar Reply
biology is my best subject
Oseni Reply
o really
Ajila
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Izadora
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Zeus
hi Guy
Charles
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daniel
hy
Kareem
How are you guys
daniel
fine and u
Kareem
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Izadora
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Kareem
Brazil
Izadora
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Kareem
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Izadora
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Hele
I'm from Nigeria, my name is Vincent. what is the relationship between volume an temperature?
Vincent
who is the father of chemistry?
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Vincent
fine
Kareem
the relationship between volume and temperature is. volume is directly proportional to temperature
Inusah
Antoine lavoisier
Ujunwa
good evening everyone my name is Maryann
Ujunwa
an acid is any substance which when dissolved in water produces hydrogen ion as its only positive ion
Ezemadu Reply
its just me or you guys also hate chemistry?
Izadora
I partially hate it
Oseni
there's some parts that I actually like to study
Izadora
sometimes
Izadora
tell me about it
Oseni
like radiation
Izadora
physics have this too
Izadora
good evening everyone my name is Maryann
Ujunwa
Why acid is sour in taste. Please don't say naturally because there are a scientific reason in all natural thing
Prabhakar Reply
since it has a negatively charge nitrogen ions
Elvis
sorry, positively hydrogen ions, which has a pH less than 7
Elvis
Corrct, as the H+ ion concentration increases acidity increases.
Aakash
because it's pH value is smaller than 7.
Raju
what is molecules
samuel
what is acid
Faree
How we make negative mass
Prabhakar Reply
How we make negative and positive matters
Prabhakar Reply
matters are neutral in general.
Rakesh
It becomes positive or negative when they either loss or gain electrones .
Rakesh
Have you any doubt regarding the first question that you had asked.
Rakesh
It also depends upon the nature of matter either it is metal or non metal.
Aakash
Basically matter never be a positive or negative. Matter can only be change into postive ion or negative ion.
Aakash
Bromine is a nonmetal liquid. Can you say that Bromine is negatively changed.
Rakesh
Because, Bromine here forming Covalent bond.
Rakesh
Isolated gaseous atom of bromine can be changed in negative charge atom.
Aakash
Practice Key Terms 5

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Source:  OpenStax, Chemistry. OpenStax CNX. May 20, 2015 Download for free at http://legacy.cnx.org/content/col11760/1.9
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