Chem 109 Exam 1 Notes

Front 1

What is the structural relation of alcohols, phenols, and ethers.

Back 1

Alcohols contain an –OH group attached to a saturated (sp3) carbon atom.
Phenols contain an –OH group attached to one of the carbons of a benzene ring (sp2).
Ethers contain an –O- atom bonded to two carbon atoms which can be either aliphatic or aromatic.

Front 2

What are some of the relations and alcohol, ether, & phenol group?

Back 2

Front 3

Are isomers possible for simple alcohols?

Back 3

No isomers are possible for the simplest alcohols: methanol, CH3OH, and ethanol, CH3CH2OH.

Front 4

How many possible isomers are possible for C3H8O?

Back 4

Front 5

The –OH group can be placed in two unique positions on each carbon skeleton:

Back 5

Front 6

An alcohol can be viewed as an alkane, cycloalkane, or alkene having a single oxygen atom inserted between one of the carbon atoms and its attached hydrogen. What are the C:H ratios for COH?

Back 6

As a result, the molecular formula of an alcohol still indicates the presence of a ring or double bond:
If the C:H ratio is the same as for an alkane, CnH2n+2, there is no ring or double bond.
If the C:H ratio is the same as for a cycloalkane or alkene, CnH2n, then either a ring or double bond is present.

Front 7

What does it mean when Alcohols are classified as primary (1°), secondary (2°), or tertiary (3°)?

Back 7

Front 8

What are some of the UPAC and common names for alcohols?

Back 8

Front 9

What are some of the properties of alcohols, ethers, and alkanes?

Back 9

Front 10

What are the two oxidations stages of alcohol?

Back 10

Stage 1: Simultaneous loss of hydrogens (dehydrogenation) from the –OH group and the adjacent C-H carbon producing a carbonyl group and a resulting compound called an aldehyde.
Stage 2: Oxidation of the –H attached to the carbonyl group of the aldehyde to –OH, producing a carboxylic acid.

Front 11

Permanganate and dichromate can be used for simple chemical diagnostic tests for primary and secondary alcohols. What are the results?

Back 11

Permanganate oxidation: MnO4- (purple solution) is converted into MnO2 (brown precipitate)
Dichromate oxidation: Cr2O72- (orange solution) is converted into Cr3+ (green solution)

Front 12

What are alkenes?

Back 12

are unsaturated hydrocarbons containing a carbon–carbon double bond—that is, two adjacent carbon atoms joined together with two bonds.
The general formula for an alkene is CnH2n , where n is an integer greater than 1.
The first (smallest) member of the alkene family is C2H4 (IUPAC name, ethene; common name, ethylene).

Front 13

What are some properties of alkenes and their IUPAC name?

Back 13

Front 14

What is the general formula for alkenes?

Back 14

Since the molecular formula for an alkene and a cycloalkane is the same, CnH2n, the formula alone is not enough to distinguish between them.
Additional information, such as their physical properties, is required to classify an unknown substance.

Front 15

What are cis isomers?

Back 15

Cis-trans isomers are the result of restricted rotation about double bonds
These isomers have the same connectivity of atoms and differ only in the arrangement of atoms in space
This puts them in the broader class of stereoisomers
The molecules below do not superpose on each other
One molecule is designated cis (groups on same side) and the other is trans (groups on opposite side)

Front 16

When is cis transformation not possible?

Back 16

Cis-trans isomerism is not possible if one carbon of the double bond has two identical groups

Front 17

What happens occurs when bromine is added to alkene?

Back 17

bromine to alkenes provides a simple chemical diagnostic test for alkenes.
Takes place rapidly
Gives a positive result visible to the naked eye.
Bromine has a deep red color which disappears shortly after addition to an alkene:

Front 18

What do you expect when bromine is attached to an unknown compound?

Back 18

Add some bromine to an unknown compound and wait a few minutes:
If the red color disappears, addition has taken place and the unknown is an alkene.
If the red color does not disappear, addition has not taken place, and the unknown is an alkane.

Front 19

Hydrogen (H2)
Halogen (F2, Cl2, Br2)
Hydrogen halide (HCl, HBr, HI)
Water

Back 19

The  bond of an alkene is sufficiently weak to undergo reaction with:
Hydrogen (H2)
Halogen (F2, Cl2, Br2)
Hydrogen halide (HCl, HBr, HI)
Water
Each of the above reagents undergoes an addition reaction with an alkene:

Front 20

What happens when bromine is added to a double bond?

Back 20

Front 21

What are some of the conditions and properties of the hydronization of alkenes?

Back 21

Hydrogen adds to alkenes in the presence of metal catalysts
Heterogeneous catalysts: finely divided insoluble platinum, palladium or nickel catalysts
Homogeneous catalysts: catalyst(typically rhodium or ruthenium based) is soluble in the reaction medium
Wilkinson’s catalyst is Rh[(C6H5)3P]3Cl
This process is called a reduction or hydrogenation
An unsaturated compound becomes a saturated (with hydrogen) compound

Front 22

What occurs with the addition of water to Alkenes?

Back 22

Addition of Water to Alkenes: Acid-Catalyzed Hydration
The reaction of alkenes with dilute aqueous acid leads to Markovnikov addition of water

Front 23

What are symmetrical reagants and its properties?

Back 23

Hydrogen and halogen are symmetrical reagents (A=B).
Hydrogen adds to a double bond:

Hint 23

At room temperature a catalyst is required for this reaction. This is indicated by writing the catalyst above the arrow connecting the reactants and the products.
A catalyst provides an alternate, lower activation energy, pathway for a chemical reaction.
Hydrogenation is an example of a reduction reaction.

Front 24

What happens when two products are formed in unequal amounts?

Back 24

When two products are possible:
Some reactions are nonselective: Both products are formed in more or less equal amounts.
Some reactions are selective: The two products are formed in unequal amounts. Major and minor products are formed.

Front 25

What are additions of asymmetrical reagents to alkenes follow what rules?

Back 25

Additions of asymmetrical reagents to alkenes follows the Markovnikov rule:
The major product formed places the incoming hydrogen atom on the carbon atom of the double bond that carried the most hydrogen atoms prior to the reaction. “The rich get richer.”

Front 26

Alkenes, as well as some other families of organic compounds, can add to one another to form what and called?

Back 26

Alkenes, as well as some other families of organic compounds, can add to one another to form a covalently linked chain of molecules called a polymer.
The individually linked molecules in the polymer are called monomers.
Examples of synthetic polymers include plastics, fibers, and rubbers.
Naturally occurring polymers include carbohydrates, proteins, and nucleic acids.

Front 27

What are some examples of polymerization?

Back 27

Front 28

Alkenes are oxidized by what?

Back 28

Alkenes are oxidized in the presence of sufficient oxygen to carbon dioxide and water:

Hint 28

Alkenes can also be selectively oxidized to alcohols, aldehydes, and ketones or carboxylic acids by a variety of laboratory oxidizing agents such as permanganate (MnO4-), dichromate (Cr2O72-), as well as with oxygen and ozone (O3) from the atmosphere.
Permanganate (purple solution  brown precipitate) and dichromate (orange solution  green solution (Cr3+)) also serve as simple chemical tests for the presence of alkenes.

Front 29

What are alkynes?

Back 29

Alkynes are hydrocarbons containing a carbon-carbon triple bond.
The general formula for an alkyne is CnH2n-2. The first member of the alkyne series is ethyne (acetylene):

Hint 29

Because of the triple bond, alkynes are more reactive than alkenes.

Front 30

What are some rules for alkynes?

Back 30

Alkynes react with the same reagents as alkenes, but with twice as much reagent, since the double bond left after the first addition is also reactive.

Front 31

Show the sequential reaction of 1-butyne with excess HCL that is show the reaction of one molecule of 1-butyne with one HCL molecule and then write a second HCL molecule. Show only the major product of each addition.

Back 31

Front 32

What are aromatic compound?

Back 32

Aromatic compounds are unsaturated hydrocarbons that do not behave like other unsaturated hydrocarbons. They have exceptional stability, far beyond what would be expected.
The simplest aromatic hydrocarbon is benzene, C6H6:

Front 33

What are some properties of carbon and hydrogen in benzene?

Back 33

All carbon and hydrogen atoms in benzene lie in one plane.
The unsaturated ring system of benzene is called the benzene ring or benzene system.
Organic compounds whose structures contain a benzene ring are called aromatic compounds.

Hint 33

Although the benzene ring system looks like a triene with alternating single and double bonds, reactions typical of double bonds do not take place.

Front 34

What does benzene look like?

Back 34

Front 35

Give me some examples of benzenes?

Back 35

Front 36

What are some examples of monosubstitued benzenes?

Back 36

Front 37

What are some examples of disubstituted benzenes?

Back 37

Certain disubstituted benzenes are named as derivatives of te monosubstituted benzene, if it has a preferred common name:h

Front 38

A phenyl or substitued phenyl group is called what?

Back 38

A phenyl or substituted phenyl group is called an aryl group (Ar).

Front 39

What are some reactions of C=C double bonds?

Back 39

The C=C double bonds in benzene are highly resistant to addition, however, the C-H bonds in benzene will undergo substitution reactions.
Halogenation, sulfonation, nitration, and alkylation reactions all result in the replacement of a hydrogen atom extending from the benzene ring with another atom or group.

Front 40

What are some reactions of C=C double bonds?

Back 40

The C=C double bonds in benzene are highly resistant to addition, however, the C-H bonds in benzene will undergo substitution reactions.
Halogenation, sulfonation, nitration, and alkylation reactions all result in the replacement of a hydrogen atom extending from the benzene ring with another atom or group.

Front 41

Summarize alkenes?

Back 41

Alkenes contain a double bond—that is, two adjacent carbons joined together with two bonds.

• The general formula for an alkene is CnH2n, which contains two fewer hydrogens than the general formula for an alkane.

• The carbon atoms of the double bond possess three sp2-hybrid orbitals with trigonal (120°) bond angles, and one unhybridized 2p orbital.

• The orbitals overlap to form one strong bond (a σ-bond) and one weak bond (a π-bond).

Front 42

Summarize Constitutional Isomers of Alkenes?

Back 42

Constitutional Isomers of Alkenes

• Constitutional isomerism exists in alkenes not only because a given formula allows different carbon skeletons, as in the alkane family, but also because it allows different placements of the double bond within a carbon skeleton.

Front 43

Summarize naming alkenes?

Back 43

• In the IUPAC system, alkenes are named on the basis of the longest continuous chain containing the double bond.

• The base name is preceded by a number indicating the position of the double bond.

• The family ending of alkene names is -ene.

• Prefixes with numbers identify any substituents attached to the longest chain.

Front 44

Summarize Cis-Trans Stereoisomerism in Alkenes?

Back 44

Cis-Trans Stereoisomerism in Alkenes

• Cis-trans (geometrical) stereoisomers exist in alkenes when each carbon atom of the double bond has two different substituents.

• The cis isomer has substituents on the same side of the double bond. The substituents are on opposite sides of the double bond in the trans isomer.

Front 45

Summarize Addition reactions of alkenes?

Back 45

Addition Reactions of Alkenes

• The presence of the weak bond in the double bond greatly increases the reactivity of alkenes relative to the low reactivity of saturated hydrocarbons.

• Various addition reactions are possible: a reagent breaks into two fragments, each of which bonds (adds) to one of the carbons of the double bond.

• Hydrogen, halogens, hydrogen halides, and water are all able to add to the alkene double bond.

• The addition of asymmetrical reagents (hydrogen halides, water) to asymmetrical alkenes proceeds in a selective manner.

• The Markovnikov rule is followed, meaning that the hydrogen fragment from the reagent adds to the carbon of the double bond that already holds more hydrogens before reaction.

Front 46

Summarize Addition Polymerization?

Back 46

Addition Polymerization

• Addition polymerization is a self-addition reaction in which large numbers of alkene molecules add to one another to form high-molecular-mass molecules called polymers.

Front 47

Summarize Oxidation of Alkenes

Back 47

Oxidation of Alkenes

• Alkenes, like other organic compounds, can undergo combustion.

• Selective oxidation is also possible.

Front 48

Summarize Alkynes?

Back 48

Alkynes

• Alkynes contain a triple bond, three bonds between two adjacent carbon atoms.

• Two of the three bonds are weak π-bonds similar to those in the alkene double bond.

• The triple bond undergoes the same reactions as the double bond does but with twice as much of the reagent.

Front 49

Summarize aromatic compounds?

Back 49

Aromatic Compounds

• Aromatic compounds contain the benzene ring, a six-membered ring with alternating double and single bonds.

• Substituted benzenes are named by IUPAC as derivatives of benzene, with prefixes indicating the substituents attached to the ring.

• Either a numbering system or the ortho-, meta-, para-system is used to indicate the positions of substituents for disubstituted benzenes.

• Only the numbering system is used for trisubstituted benzenes.

• Some monosubstituted benzenes have common names that are accepted by IUPAC and used as the basis for naming their di- and trisubstituted relatives.

Front 50

Summarize Reactions of Aromatic Compounds?

Back 50

Reactions of Aromatic Compounds

• The benzene ring has exceptional stability.

• Benzene is inert to the addition of halogens, hydrogen halides, sulfuric acid, and water—reagents that add to alkene double bonds.

• Benzene and other aromatic compounds undergo substitution reactions with halogens, nitric acid, sulfur trioxide, and alkyl halides.

• Alkylbenzenes undergo oxidation of the alkyl group, but the benzene ring itself remains intact.

Front 51

Summarize alkene additions and polymerization?

Back 51

Front 52

What is organic chemistry?

Back 52

Organic chemistry is the study of organic compounds, compounds containing the element carbon. All other compounds are classified as inorganic.
A few carbon containing compounds are classified as inorganic:
CO, CO2, carbonates such as H2CO3 and Na2CO3, bicarbonates such as NaHCO3, and cyanides such as HCN and NaCN.

Front 53

What is molecular and structural formula?

Back 53

The molecular formula of a compound indicates the numbers of atoms of each element present but does not indicate how they are connected:
CH4, C6H12O6, CH4NO, etc.
The structural formula of a compound indicates both the numbers and types of atoms and how they are connected.

Front 54

What is the combining power of organic compounds?

Back 54

Front 55

Summarize the family of organic compounds?

Back 55

Front 56

Summarize family of organic compounds 2?

Back 56

Front 57

What are some rules of organic compounds?

Back 57

Aldehydes, ketones, carboxylic acids, esters, and amides possess the carbonyl group, a carbon–oxygen double bond, but differ in the atom or group of atoms connected to the carbon of the carbonyl group.
The carbonyl carbon of an aldehyde is directly connected to at least one hydrogen.
The carbonyl carbon of a ketone is directly connected to carbon atoms, not hydrogen.
The carbonyl carbon of carboxylic acids and esters is connected by a single bond to an oxygen, but these families differ in what is connected to that oxygen.
In carboxylic acids, a hydrogen is connected to the oxygen; in esters, the oxygen is connected to a second carbon atom.
An amide has a nitrogen connected to the carbonyl carbon.

Front 58

What are hydrocarbons and the difference between saturated and unsaturated compounds?

Back 58

Hydrocarbons contain only carbon and hydrogen and can be subdivided into the two classes:
Saturated hydrocarbons: Undergo few chemical reactions
Unsaturated hydrocarbons: Undergo many chemical reactions

Front 59

What are alkanes?

Back 59

Alkanes consist entirely of C-C and C-H single bonds.
Alkanes have the general formula: CnH2n+2, where n is an integer greater than 0.

Front 60

What are the first four alkanes and its properties?

Back 60

The first four alkanes are gases and the others are liquids near 20o C.

Front 61

Summarize alkane hybridization?

Back 61

The first four alkanes are gases and the others are liquids near 20o C.

Front 62

Define free rotations and show examples?

Back 62

A single bond between two atoms possesses free rotation.
Free rotation allows molecules to have different conformations, or different orientations resulting only from rotations about its single bonds

Front 63

Show different examples or constiutional isomers for butane?

Back 63

I, II, and III represent the same conformation, shown in different orientations. IV is a different conformation. V does not specify a conformation. VI is an expanded structural formula and VII is a condensed structural formula.

Front 64

Summarize constitutional isomers?

Back 64

Front 65

What is a common mistake for constitutional isomers?

Back 65

It is important in working out the answer to this problem not to incorrectly show two different structural formulas of the same isomer.
For example, including structure 4 along with structures 1, 2, and 3 is a mistake because structures 2 and 4 represent the same compound.

Front 66

Back 66

Front 67

The IUPAC system uses a short list of the alkyl groups normally found in organic molecules: What are they?

Back 67

Front 68

Summarize the different alkyle groups?

Back 68

Front 69

Back 69

Front 70

Summarize naming alkanes

Back 70

Front 71

Back 71

Front 72

Summarize cycloalkanes and rules?

Back 72

Cycloalkanes are often represented by a condensed structural formula in the form of a geometrical shape:

Front 73

Cycloalkanes possess constitutional isomers of the same formula. Show For C5H10:

Back 73

Front 74

Stereoisomers are difference in what aspects?

Back 74

Stereoisomerism results from differences in configuration, not connectivity.