Ch. 2 - Molecular RepresentationsWorksheetSee all chapters
All Chapters
Ch. 1 - A Review of General Chemistry
Ch. 2 - Molecular Representations
Ch. 3 - Acids and Bases
Ch. 4 - Alkanes and Cycloalkanes
Ch. 5 - Chirality
Ch. 6 - Thermodynamics and Kinetics
Ch. 7 - Substitution Reactions
Ch. 8 - Elimination Reactions
Ch. 9 - Alkenes and Alkynes
Ch. 10 - Addition Reactions
Ch. 11 - Radical Reactions
Ch. 12 - Alcohols, Ethers, Epoxides and Thiols
Ch. 13 - Alcohols and Carbonyl Compounds
Ch. 14 - Synthetic Techniques
Ch. 15 - Analytical Techniques: IR, NMR, Mass Spect
Ch. 16 - Conjugated Systems
Ch. 17 - Aromaticity
Ch. 18 - Reactions of Aromatics: EAS and Beyond
Ch. 19 - Aldehydes and Ketones: Nucleophilic Addition
Ch. 20 - Carboxylic Acid Derivatives: NAS
Ch. 21 - Enolate Chemistry: Reactions at the Alpha-Carbon
Ch. 22 - Condensation Chemistry
Ch. 23 - Amines
Ch. 24 - Carbohydrates
Ch. 25 - Phenols
Ch. 26 - Amino Acids, Peptides, and Proteins

We can group millions of different molecules into families of similar functionality.

Concept #1: Why we need functional groups. 

Hydrocarbons

Concept #2: Recognizing different types of hydrocarbons. 

  • All carbon groups regardless of size can be symbolized using an –R group.
  • When an alkane is attached to a greater carbon chain, it is given a –yl suffix
    • An alkane turns into an alkyl group.  

Concept #3: How to assign degrees to carbons and hydrogens. 

  • Carbons are given a “degree” based on how many other carbons they are attached to.
    • Degrees are expressed as primary, secondary, tertiary and quaternary (1o, 2o, 3o, 4o)
    • Hydrogens possess the SAME degree as the carbon they are attached to 

Example #1: Determine the degree of the indicated carbons and hydrogens. 

Alkyl Halides

Concept #4: Recognizing alkyl halides. 

  • Condensed Structure = -RX
  • The degree of the alkyl halide is determined the same exact way as hydrogen. 

Example #2: Use your knowledge of hydrogen degrees to assign degrees to the following alkyl halides. 

Functional Groups without Carbonyls

Carbonyls are C=O bonds within a molecule. First we’ll learn about common functional groups that don’t contain these.  

Concept #5: How to recognize alcohols, amines and ethers.  

  • Alcohol Condensed Structure = -ROH
  • Amine Condensed Structure = -NH3, RNH2, R2NH, R3N
  • Ether Condensed Structure = ROR

These three functional groups completely change when they have a carbonyl next to them!

Functional Groups with Carbonyls

Concept #6: How to recognize carboxylic acids, amides and esters.  

  • Carboxylic Acid Condensed Structure = -COOH
  • Amide Condensed Structure = -CONH2
  • Ester Condensed Structure = -COOR

As you see, these functional groups are similar to the other ones, but have different names due to the adjacent carbonyl. 

Adding Carbonyls to Hydrocarbons

Concept #7: The difference between aldehydes and ketones. 

Concept #8: How to write the condensed structures for aldehydes and ketones. 

  • Ketone Condensed Structure = -COR
  • AldehydeCondensed Structure = -CHO

These condensed structures aren’t very obvious. So just apply them to memory!

Nitriles

Concept #9: How to recognize nitriles. 

  • Nitrile Condensed Structure = -CN
Aromatic Hydrocarbons

Concept #10: The difference between phenyl and benzyl groups.  

Example #3: Identify all the functional groups in the following compound. Show degrees where applicable.

Other Carbonyl Compounds

Concept #11: Recognizing acyl chlorides and anhydrides.

Concept #12: Recognizing sulfur compounds

Since sulfur is directly under oxygen in the periodic table, it makes analogous structures. These have different names depending on whether the sulfur is terminal (like alcohol) or internal (like ether). 

  • Thiol Condensed Structure = -RSH
  • Sulfide Condensed Structure = RSR

 

Alright, now who's ready for some Practice Questions? Let's see if you can name all of the functional groups in the following 3 questions. 

 

If you get stuck, just pause the video and scroll up! 

Practice: PRACTICE: The following molecule contains several functional groups. Of the choices given, select the most appropriate answer (not all functional groups may be listed). 

Practice: PRACTICE: Identifying functional groups. Select the most appropriate answer. 

REMEMBER the A-TEAM gets degrees!

 

That is Alcohols, Alkyl Halides and Amines. 

Also, don't forget about Amides, they are part of the A-team as well. :)

Practice: PRACTICE: Identifying functional groups. Select the most appropriate answer. 

Congratulations, you made it to the end! Now let's move on to the next topic. 

Additional Problems
Identify all of the functional groups in Crixivan, an important drug in the treatment of AIDS.
For each of the molecules below write the name of the major functional group present on the line below each structure.
Identify ALL of the functional groups in the following molecule. Assign degree of functional group when appropriate.
Cyclic compounds of the general type shown here are called lactones. What functional group does a lactone contain?
Identify ALL of the functional groups in the following molecule. Assign degree of functional group when appropriate.
Circle the only alkene:
Which structure(s) contain(s) a tertiary amine?
Which structure contain(s) a tertiary alcohol?
Provide a LINE DRAWING that exemplifies each of the following functional groups below. Draw a real molecule, not just the generic formula using the letter “R”, and your molecule must contain exactly 5 carbons.  
Provide a LINE DRAWING that exemplifies each of the following functional groups below. Draw a real molecule, not just the generic formula using the letter “R”, and your molecule must contain exactly 5 carbons.
Draw a specific example of the Functional Group for each of the names listed below. You can use a methyl group in place of R for your example.
In the structure shown below, the functional groups in the triangle, rectangle, pentagon and circle (in this same order) are a) amine, ketone-ether, ether, amide b) amide, ester, ether, ketone-amine c) amine, ester, ether, amide d) amine, ester, ether, ketone-amine
Which of these molecules contains  amide, ketone, ether, and ester functional groups?
For each of the molecules below write the name of the major functional group present on the line below each structure. (SPELLING COUNTS)
Identify the functional groups in the following molecule: a. ketone, aromatic, 1° alcohol, ester b. aldehyde, 3° alcohol, aromatic, ketone c. ester, aromatic, 1° alcohol, 1° alcohol d. ketone, 1° alcohol, ether, aromatic e. aldehyde, ester, aromatic, 1° alcohol
Circle and label FOUR (4) different functional groups in the following molecule.
“Amoxicillin is an antibiotic useful for the treatment of a number of bacterial infections. It is the first line of treatment for middle ear infections.” (Wikipedia, 9/4/2015). CIRCLE and LABEL FOUR (4) different functional groups in the molecule.
Look at the entire structure of Nasonex. How many methyl groups are present in Nasonex? A. 0 B. 6 C. 2 D. 3 E. 4 F. 5 G. 6 H. 7 I. 8 J. None of these
Look at the entire structure of Lamisil. How many methylene groups are present in the structure of this molecule?   A. 0      E. 4      I. 8 B. 1      F. 5      J. None of these C. 2      G. 6 D. 3      H. 7
For the structure given below circle all tertiary carbons and star all primary carbons.
What functional group(s) are in the molecule below? a) Amide b) Ether c) Ketone d) Aldehyde e) Ester
Label the circled groups with the numbers that correspond to the following:  1 = Strained 7 membered ring system. 2 = Amide 3 = Ether 4 = sp2 hybridized carbon 5 = Carboxylic acid
Categorize the following functional groups (use primary, secondary, tertiary descriptions when appropriate).   
Capsaicin, found in peppers, has the following structure. What is the molecular formula for capsaicin? Identify the functional groups.
The structure of L-DOPA, the precursor to the neurotransmitters dopamine, norepinephrine, and adrenaline, is below. MARK all the FAMILIES to which this molecule belongs because of its functional groups. A. Alkane B. Alkene C. Arene D. Alcohol  E. Ether F. Amine  G. Ketone H. Carboxylic acid  I. Ester  J. Amide
For the following functional groups either (a) provide the name with correct spelling or (b) draw a molecule in skeletal form containing that functional group in the space provided.
Everolimus (Zortress) is a derivative of sirolimus and works similarly to sirolimus as an inhibitor of mammalian target of rapamycin (mTOR). It is currently used as an immunosuppressant to prevent rejection of organ transplants (kidney and liver) and treatment of renal cell cancer and other tumours. Identify ALL of the functional groups present in everolimus, indicating  degree of the functional group when appropriate. 
Consider the structure below and answer the following questions. 
Categorize the following functional groups (use primary, secondary, tertiary descriptors when appropriate). 
The alkane below has how many 1o, 2o, 3o, 4o degree carbons:
Classify each of the following compounds as an alkane, alkene, alkyne, alcohol, aldehyde, amine, and so forth.  
Classify each of the following compounds as an alkane, alkene, alkyne, alcohol, aldehyde, amine, and so forth.
Which structure contains a 3° alkyl halide?  
Classify each of the following compounds as an alkane, alkene, alkyne, alcohol, aldehyde, amine, and so forth.
Classify each of the following compounds as an alkane, alkene, alkyne, alcohol, aldehyde, amine, and so forth.  
Classify each of the following compounds as an alkane, alkene, alkyne, alcohol, aldehyde, amine, and so forth.
Classify each of the following compounds as an alkane, alkene, alkyne, alcohol, aldehyde, amine, and so forth.  
Identify all of the functional groups in each of the following compounds:
Identify all of the functional groups in each of the following compounds:  
Identify all of the functional groups in each of the following compounds:
Identify all of the functional groups in each of the following compounds:  
The following compound is an intermediate in the synthesis of a gelator, which is a compound capable of self-assembling to form a gel in an organic liquid (Soft Matter 2012, 8, 5486–5492).  (a) Identify each functional group in the molecule. 
Identify all of the functional groups in each of the following compounds:
Many compounds with desirable medicinal properties are isolated from natural sources and are thus referred to as natural products. However, a compound’s medicinal properties are often known before the structure of the compound has been determined. Below are examples of compounds where the first proposed structure was incorrect (Angew. Chem. Int. Ed. 2005, 44, 1012–1044). In each case, the corresponding correct structure is also shown. Identify all functional groups in each pair of compounds and then compare the similarities and differences between their molecular structures. 
Identify all of the functional groups in each of the following compounds:
Many compounds with desirable medicinal properties are isolated from natural sources and are thus referred to as natural products. However, a compound’s medicinal properties are often known before the structure of the compound has been determined. Below are examples of compounds where the first proposed structure was incorrect (Angew. Chem. Int. Ed. 2005, 44, 1012–1044). In each case, the corresponding correct structure is also shown. Identify all functional groups in each pair of compounds and then compare the similarities and differences between their molecular structures. 
Identify all of the functional groups in each of the following compounds:
There are four alkyl bromides with the formula C 4H9Br. Write their structural formulas and classify each as to whether it is a primary, secondary, or tertiary alkyl bromide.
Classify the following alcohols as primary, secondary, or tertiary:  
Classify the following alcohols as primary, secondary, or tertiary:
Classify the following alcohols as primary, secondary, or tertiary:  
Classify the following alcohols as primary, secondary, or tertiary:
Classify the following alcohols as primary, secondary, or tertiary:  
Classify the following amines as primary, secondary, or tertiary:
Classify the following amines as primary, secondary, or tertiary:  
Classify the following amines as primary, secondary, or tertiary:
Classify the following amines as primary, secondary, or tertiary:  
Classify the following amines as primary, secondary, or tertiary:
Classify the following amines as primary, secondary, or tertiary:  
Write structural formulas for each of the following: (c) A secondary alcohol with the formula C3H6O.
Write structural formulas for each of the following: (d) A tertiary alcohol with the formula C4H8O.
How many tertiary hydrogens atoms are present in the molecule shown below?  a. six b. three c. one d. four
The compound  zoapatanol  was isolated from the leaves of a Mexican plant. Classify each oxygen in zoapatanol according to the functional group to which it belongs. If an oxygen is part of an alcohol, classify the alcohol as primary, secondary, or tertiary. 
In the molecule  shown below, how many primary alcohols are present? A) none B) 1 C) 2 D) 3 E) 4
In the molecule shown below, how many benzene rings are present? A) none B) 1 C) 2 D) 3 E) 4
Write structural formulas for each of the following: (g) Three secondary alkyl halides with the formula C5H11Br.
In the molecule shown below, how many secondary (2°) amines are present? A) none B) 1 C) 2 D) 3 E) 4
Consult Table 4.1 and classify each nitrogen-containing functional group in the anesthetic lidocaine according to whether it is an amide, or a primary, secondary, or tertiary amine. 
Write structural formulas for each of the following: (l) A secondary amine with the formula C3H9N.
Identify all of the functional groups in the following molecule.
Uscharidin is the common name of a poisonous natural product having the structure shown. Locate all of the following in uscharidin:   (a) Alcohol, aldehyde, ketone, and ester functional groups
The questions below refer to the structure of Zanamivir, which is shown below. This is a line-angle structure. Lone pairs are not shown explicitly, but every atom in this molecule has a formal charge of zero.  
Uscharidin is the common name of a poisonous natural product having the structure shown. Locate all of the following in uscharidin:  (b) Methylene groups 
Look at the  entire structure of Atenolol. How many  methylene groups are present in the structure of this molecule? A. 0 B. 1 C. 2 D. 3 E. 4 F. 5 G. 6 H. 7 I. 8 J. None of these
Uscharidin is the common name of a poisonous natural product having the structure shown. Locate all of the following in uscharidin:  (c) Primary carbons 
Classify each molecule as an aldehyde, ketone, or neither.
Identify ALL the functional groups in the following molecule, including their degree if applicable.
Label the highlighted functional groups in this molecule.
Identify ALL the functional groups in the following molecule, including their degree if applicable.
Identify ALL the functional groups in the following molecule, including their degree if applicable.
Identifying Functional Groups:
Identifying Functional Groups:
Select the name of the family to which the following compound belongs.a. acyl chlorideb. amidec. esterd. anhydridee. carboxylic acid
Name the family of compounds to which the following compound belongs.
Identify the functional groups in the molecule of penicillin
Consider the compound below to answer the following questions. (a) How many methine hydrogens are there?   (b) How many primary Cs are there?   (c) Give the molecular formula of this compound.    (d) How many quaternary Cs are there?   (e) How many secondary alkyl groups exist as substituents?  
Identify the functional groups in the following molecule:
Formaldehyde, CH2O, is used as an embalming agent. Draw the structure of CH 2O including lone pairs.
Classify each molecule as an aldehyde, ketone, or neither.
For the molecule pictured:i) Identify the circled functional groups;ii) How many lone pairs of electrons does this molecule have?iii) How many 1° hydrogens are present?iv) How many sp2 carbons are present?v) how many 3° carbons are present?vi) How many unit of unsaturation are present?
Identify the functional groups in the following molecule.
What is the name of the functional group attached at C5 for the molecule given below? (Hint: use the IUPAC name)A) chlorideB) methylC) ketoneD) isobutylE) benzyl
Identify the amines as primary, secondary, tertiary, or quaternary.
Identify the functional groups in the following molecule. 
What is the name of the NH 2 functional group?
For each of the molecules below write the name of the major functional group present on the line below each structure.
Identify all functional groups including degrees, if applicable, in this molecule. a) 2o Alcohol, 2o halide, Aldehyde, Ether, Alkyne and Alkene, 2o amine b) 2o amine, 2o alchohol, 1o halide, ketone, alkyne and alkene, ester c) Aldehyde, alkyne and alkene, 2o amine, ester, 1o alcohol, 1o halide d) 1o halide, alkyne and alkene, 2o alcohol, 1o amine, aldehyde, ester 
For the following structure
For the following structure:
Identify the functional group(s) in the following compound. 
Identify the functional group(s) in the following compound. 
Identify the functional group(s) that appear in betaxolol. This compound is in a class of drugs called beta-blockers, which are used to lower blood pressure, lower heart rate, reduce angina (chest pain), and reduce the risk of recurrent heart attacks. AlcoholEtherAreneCarboxylic AcidAldehydeEsterAmineAlkeneKetone 
Which functional group does not contain an oxygen atom? a. ketoneb. alcoholc. aldehyded. carboxylic acide. aminef. esterg. amideh. ether
Which is the correct structures for benzaldehyde 
What functional groups are present on this molecule? a. Carboxyl and aldehyde b. Hydroxyl and aldehyde c. Hydroxyl and ketone d. Hydroxyl and ester e. Carboxyl and ketone 
Select the compound below that contains a carboxylic acid functional group. a. CH3COOCH3b. CH3COOHc. CH3OCH3d. CH3COCH3 
Which of those compounds considered cyclic ether? 
Which of the following is a ketone?Select one:  
Which of the following compounds is a phenol?  
Which of the following is a tertiary amine? 
Which of the following in neither an aldehyde nor a ketone? Select one: 
The molecule below is largely responsible for the odor and flavor of pears. Which organic family is present ? 
Which compound is an ester? 
What common functional group in biomolecules is depicted in the figure below? (Where R represents any substituents.) a. Aldehyde b. Carbonylc. Ester d. Ketonee. Resehyde
Which of the following is a correct name for the following substance?Select one:a. benzeneb. benzaldehydec. phenold. benzaketonee. benzoic acid 
Identify all the functional groups found in vanillin?
Identify the following molecule as: A. an alcohol B. a phenol. C. an aromatic hydrocarbon. D. an acid.
What functional group is present in this compound? Select one:a. amineb. carboxylic acidc. alcohold. aldehydee. ketone 
Which of these compounds is a carboxylic acid? Select one:a. A, B and Cb. B onlyc. B and C onlyd. A and B onlye. A only 
Which of the following is tertiary amine?
Draw the structure(s) of all alkane(s) that have 6 carbons, 1 of which is tertiary.• You do not have to consider stereochemistry. • If more than one structure fits the description, draw them all. • Draw one structure per sketcher. Add additional sketchers using the drop-down menu in the bottom right corner. • Separate structures with + signs from the drop-down menu. 
Which of these molecules are alcohols? Check all that apply.