Chem 109 Chapter 6 Exam 2

Front 1

The common structural feature of all aldehydes and ketones is?

Back 1

The common structural feature of all aldehydes and ketones is the carbonyl functional group.

Front 2

The common structural feature of all aldehydes and ketones is?

Back 2

The common structural feature of all aldehydes and ketones is the carbonyl functional group.

Front 3

Show me the funtional groups of aldehydes and ketones and the the carboxyl group.

Back 3

Front 4

Other families containing the carbonyl group contain a heteroatom—What is an heteroatom?

Back 4

Other families containing the carbonyl group contain a heteroatom—an oxygen in carboxylic acids and esters, and a nitrogen in amides.

Front 5

Give pictoral examples of heteroatoms?

Back 5

Front 6

What are other examples of families containing carbonyl groups?

Back 6

Front 7

Aldehydes and ketones are related to alcohols in the same way that alkenes are related to alkanes: the loss of two hydrogen atoms: Show me?

Back 7

Front 8

The C=O double bond in aldehydes and ketones acts like the C=C double bond in alkenes: the molecular formula of an aldehyde or ketone contains two fewer hydrogen atoms than the parent alcohol.

Back 8

Front 9

Both the carbon and oxygen atoms in the carbonyl group are sp2 hybridized. What do they contain?

Back 9

Both the carbon and oxygen atoms in the carbonyl group are sp2 hybridized. The carbonyl group contains one strong σ-bond and a weaker π-bond.

Front 10

The bonds angles about the carbonyl group are close to 120°. Show me?

Back 10

Front 11

Aldehydes and ketones can have different constitutional isomers based on what?

Back 11

Aldehydes and ketones can have different constitutional isomers based on different carbon skeletons, and on the placement of the carbonyl group.

Front 12

Both compounds have the same formula C3H6O: Show me how?

Back 12

Front 13

The IUPAC naming system for aldehydes and ketones is a variation of the naming system for alkanes: Show me how?

Back 13

Front 14

Show me IUPAC and common names of Aldehydes and Ketones.

Back 14

Front 15

Show me the physical Properties of Aldehydes and Ketones?

Back 15

The physical properties of aldehydes and ketones depend upon the polar nature of their carbonyl group.
Higher boiling and melting points than those of the corresponding hydrocarbons but lower than those of the corresponding alcohols.
Almost the same water solubility as that of alcohols.

Front 16

The carbonyl group is highly polarized: Show me?

Back 16

Front 17

The true structure is between these two extremes, or a blend of the two structures. The carbonyl carbon possesses a partial positive charge and the carbonyl oxygen a partial negative charge. Show me

Back 17

Front 18

Show me examples of boiling points and ketones?

Back 18

Front 19

Show me the relation of secondary attraction forces and boiling point.

Back 19

Front 20

What are some of the relations between boiling points of alcohols, aldehydes, and alkanes with molecular mass?

Back 20

Front 21

What are some physical Properties of Aldehydes and Ketones?

Back 21

Aldehydes and ketones have boiling points considerably lower than those of alcohols, however, they all have about the same water solubility.
Aldehydes and ketones are hydrogen bond acceptors and thus can interact with the hydrogen bond donors of water molecules.
Aldehydes and ketones cannot hydrogen bond with each other, however, because they lack hydrogen bond donating groups.

Front 22

Aldehydes and ketones undergo combustion reactions with oxygen to carbon dioxide and water.Selective oxidations using permanganate (MnO4-) or dichromate (Cr2O72-) yield: Show me?

Back 22

Front 23

The selective oxidation of aldehydes is used commercially for the synthesis of what?

Back 23

The selective oxidation of aldehydes is used commercially for the synthesis of carboxylic acids.

Front 24

The oxidation of aldehydes also takes place slowly upon exposure to air. Ketones are what?

Back 24

The oxidation of aldehydes also takes place slowly upon exposure to air. Ketones are not affected.

Front 25

Dichromate and permanganate oxidations are useful tests for distinguishing aldehydes from what? They cannot distinguish aldehydes from primary and secondary alcohols and alkenes, however.

Back 25

Dichromate and permanganate oxidations are useful tests for distinguishing aldehydes from ketones. They cannot distinguish aldehydes from primary and secondary alcohols and alkenes, however.

Front 26

Reagents such as Tollens's reagent can distinguish from what to what?

Back 26

Reagents such as Tollens's reagent can distinguish aldehydes from ketones, primary and secondary alcohols and alkenes.

Front 27

What is Tollens's reagent and properties?

Back 27

Tollens's reagent is colorless alkaline solution of a silver-ammonia complex ion, [Ag(NH3)2]+, which reacts with aldehydes to form a shiny gray precipitate of silver metal. The silver usually coats the surface of the test tube, giving the appearance of a silver mirror.

Front 28

What is Benedict’s reagent and its properties?

Back 28

Benedict’s reagent is a blue, alkaline solution of copper (II) ion stabilized as its polyatomic ion with citrate anion.

Front 29

In the presence of an -hydroxy aldehyde, the blue color disappears and is replaced by a red precipitate of what?

Back 29

In the presence of an -hydroxy aldehyde, the blue color disappears and is replaced by a red precipitate of Cu2O.

Front 30

Simple aldehydes such as acetaldehyde and benzaldehyde do not give what with Benedict’s reagent?

Back 30

Simple aldehydes such as acetaldehyde and benzaldehyde do not give positive tests with Benedict’s reagent.

Front 31

Only alpha-hydroxy aldehydes give what with Benedict’s reagent?

Back 31

Only alpha-hydroxy aldehydes give a positive test with Benedict’s reagent.

Front 32

Show me the relation of test with hydroxy aldehydes and test?

Back 32

Front 33

The alpha-hydroxy ketones are the only ketones which give a positive test with Benedict’s reagent.

Back 33

Front 34

Benedict’s reagent detects glucose and certain other carbohydrates and thus can distinguish them from what?

Back 34

Benedict’s reagent detects glucose and certain other carbohydrates and thus can distinguish them from simple aldehydes and ketones, alcohols, and other compounds.

Front 35

Aldehydes can be reduced to primary alcohols and ketones to secondary alcohols. The reduction process is the reverse of the oxidation process already described.

Back 35

Front 36

Two methods of reduction are useful for aldehydes and ketones.

Catalytic hydrogenation:

Hydride reduction:

Show me?

Back 36

Front 37

In hydride reduction, a metal hydride is employed. Metal hydrides are a source of H- ions: Show me?

Back 37

Front 38

The actual mechanism of the hydride reduction involves an initial transfer of a hydride ion to the carbonyl carbon, followed by a transfer of H+ from water to the carbonyl oxygen: Show me?

Back 38

Front 39

The reagents must be added sequentially because water is more reactive to the hydride than is the carbonyl group. Show me?

Back 39

Front 40

Catalytic hydrogenation reduces both carbon-carbon and carbon-oxygen double bonds. Hydride reduction is more selective and reduces only carbon-oxygen double bonds.
Hydride reductions in biological systems are accomplished by an organic compound called nicotinamide adenine dinucleotide (NADH). Show me?

Back 40

Front 41

Nadh is the source of Hydride ions. Show me?

Back 41

Front 42

Back 42

Front 43

Aldehydes and ketones react with alcohols to form hemiacetals and acetals. Show me?

Back 43

Front 44

Hemiacetals and acetals are important structures what?

Back 44

Hemiacetals and acetals are important structures in carbohydrates.

Front 45

What are some of the properties of hemiacetals?

Back 45

The products formed from ketones were previously called hemiketals and ketals to distinguish them from the products formed from aldehydes.
Most hemiacetals are unstable and cannot be isolated.
The equilibrium forming a hemiacetal lies far to the left, or to the reactant side of the reaction.
The equilibrium forming an acetal from a hemiacetal lies far to the right, or to the product side of the reaction.

Front 46

Acetals can be isolated if excess alcohol is present, in which case Le Chatelier’s principle applies, and the favorable second reaction shifts the first reaction to the right. Show me?

Back 46

Front 47

Both hemiacetals and acetals have two different oxygens bonded to the same carbon. In acetals, both oxygens are in –OR groups; in hemiacetals, one oxygen is in an –OH group and the other is in an –OR group. Show me?

Back 47

Front 48

Hemiacetal and acetal formations are reversible reactions: How?

Back 48

Hemiacetal and acetal formations are reversible reactions:
In the presence of excess water and an acid catalyst, an acetal is converted into its parent aldehyde or ketone.
In the presence of excess alcohol and an acid catalyst, an aldehyde or ketone is converted into its corresponding acetal.

Front 49

The reaction of an acetal with water is an example of a hydrolysis reaction. How?

Back 49

The reaction of an acetal with water is an example of a hydrolysis reaction: an organic molecule reacting with water and splitting into two parts, one of which combines with the H+ from a water molecule and the other with the OH- from the water molecule.

Front 50

In animals, the hydrolysis of acetal groups is the first step in what?

Back 50

In animals, the hydrolysis of acetal groups is the first step in the digestive breakdown of starch and other carbohydrates in the digestive tract.

Front 51

Back 51

Front 52

Structural Features of Aldehydes and Ketones

• Aldehydes and ketones contain the what group?

Back 52

Structural Features of Aldehydes and Ketones

• Aldehydes and ketones contain the carbonyl group (C=O).

Front 53

An aldehyde has at least one what directly attached to the carbon of the carbonyl group?

Back 53

An aldehyde has at least one hydrogen atom directly attached to the carbon of the carbonyl group.

Front 54

A ketone has only what type of atoms, directly attached to the carbon of the carbonyl group?

Back 54

A ketone has only carbon atoms, no hydrogen atoms, directly attached to the carbon of the carbonyl group.

Front 55

The C:H ratio for an aldehyde or ketone is what fewer than the corresponding alcohol or alkane?

Back 55

The C:H ratio for an aldehyde or ketone is two hydrogens fewer than the corresponding alcohol or alkane.

Front 56

Naming Aldehydes and Ketones

• In the IUPAC system, aldehydes and ketones are named by identifyingthe what chain containing the carbonyl group?

Back 56

Naming Aldehydes and Ketones

• In the IUPAC system, aldehydes and ketones are named by identifying the longest continuous carbon chain containing the carbonyl group.

Front 57

Aldehydes are named as what?

Back 57

Aldehydes are named as alkanals.

Front 58

Ketones are named as what?.

Back 58

Ketones are named as alkanones.

Front 59

For ketones, the position of the carbonyl carbon is indicated by a what in front of the name?

Back 59

For ketones, the position of the carbonyl carbon is indicated by a number in front of the name.

Front 60

For aldehydes, no number is needed, because the carbonyl carbon is always where?

Back 60

For aldehydes, no number is needed, because the carbonyl carbon is always C1.

Front 61

Prefixes preceded by numbers indicate what?

Back 61

Prefixes preceded by numbers indicate the substituents attached to the longest chain.

Front 62

Prefixes preceded by numbers indicate the what?

Back 62

Prefixes preceded by numbers indicate the substituents attached to the longest chain.

Front 63

C6H5–CHO is named what?

Back 63

C6H5–CHO is named benzaldehyde.

Front 64

What are used for some aldehydes and ketones?

Back 64

Common names are used for some aldehydes and ketones.

Front 65

Common ketone names are obtained by how?

Back 65

Common ketone names are obtained by naming the groups attached to the carbonyl carbon, followed by the word ketone.

Front 66

Physical Properties of Aldehydes and Ketones

• Aldehydes and ketones have boiling and melting points intermediate between those of hydrocarbons and alcohols, a consequence of their dipole–explain?

Back 66

Physical Properties of Aldehydes and Ketones

• Aldehydes and ketones have boiling and melting points intermediate between those of hydrocarbons and alcohols, a consequence of their dipole–dipole secondary forces being intermediate in strength between the London forces in hydrocarbons and the hydrogen-bond forces in alcohols.

Front 67

Aldehydes and ketones are only what soluble than alcohols in water?

Back 67

Aldehydes and ketones are only slightly less soluble than alcohols in water.

Front 68

Although aldehydes and ketones cannot hydrogen bond with themselves, they can hydrogen bond with what?

Back 68

Although aldehydes and ketones cannot hydrogen bond with themselves, they can hydrogen bond with water.

Front 69

Chemical Reactions of Aldehydes and Ketones

• Aldehydes, but not ketones, undergo oxidation with several selective oxidizing agents—what are these agents?

Back 69

Chemical Reactions of Aldehydes and Ketones

• Aldehydes, but not ketones, undergo oxidation with several selective oxidizing agents—dichromate, permanganate, and Tollens’s reagents.

Front 70

Dichromate and permanganate distinguish what?

Back 70

Dichromate and permanganate distinguish aldehydes from ketones but not from primary and secondary alcohols or from alkenes, which also give positive tests.

Front 71

Tollens’s reagent is more selective than dichromate and permanganate,and distinguishes what?

Back 71

Tollens’s reagent is more selective than dichromate and permanganate, distinguishing aldehydes from ketones, alcohols, and alkenes.

Front 72

Benedict’s reagent is useful for distinguishing what?

Back 72

Benedict’s reagent is useful for distinguishing –hydroxy aldehydes and -hydroxy ketones from other compounds.

Front 73

Aldehydes and ketones undergo addition reactions with what?

Back 73

Aldehydes and ketones undergo addition reactions with hydrogen, hydrides, and alcohols.

Front 74

Aldehydes and ketones are reduced to what?

Back 74

Aldehydes and ketones are reduced to primary and secondary alcohols, respectively.

Front 75

Explain reduction of H2 and Pt or the sequential addition of hydride followed by water with NADH?

Back 75

Front 76

Explain Hemiacetal and acetal formation by reaction.

Back 76