Deck 25: Lipids

Question 1

What IR stretch would most readily distinguish carnauba wax from paraffin wax?

Answer 1

Carnauba wax is a correct wax, an ester of a fatty acid and a long chain alcohol, while paraffin wax is a mixture of high molecular weight hydrocarbons. The carbonyl stretch of the ester functionality in carnauba would readily distinguish it.

Question 2

________ lipids are those that can be easily hydrolyzed to simpler constituents.

Answer 2

Complex

Question 3

Name two of the three predominant groups of simple lipids.

Answer 3

steroids, prostaglandins, terpenes

Question 4

Which of the following peaks would one expect to observe as a major, strong peak in the IR spectrum of a lipid wax?

A) 3200-3500 cm^-1
B) 2710 cm^-1
C) 2200 cm^-1
D) 1730 cm^-1
E) 1620 cm^-1

Question 5

Which of the following is a complex lipid?

A) testosterone
B) tristearin
C) arachidic acid
D) sodium palmitate
E) b-carotene

Question 6

Which best describes the lipid shown below?

A) wax
B) triglyceride
C) saturated fatty acid
D) unsaturated fatty acid
E) lecithin

Question 7

Which of the following terms best describes the compound below? CH₃(CH₂)₂₆CO₂CH₂(CH₂)₃₂CH₃

A) a fat
B) an oil
C) a terpene
D) an unsaturated triglyceride
E) a wax

Question 8

Which of the following lipids is an example of a simple lipid?

A) fat
B) terpene
C) oil
D) wax
E) none of the above

Question 9

How many molecules of fatty acid are needed to produce one molecule of a fat or oil?

A) 1
B) 1.5
C) 2
D) 3
E) 6

Question 10

When spermaceti is heated in aqueous potassium hydroxide, CH₃(CH₂)₁₄CH₂OH and CH₃(CH₂)₁₄CO₂-K⁺ are formed. Provide the structure of spermaceti.

Question 11

Which of the following terms best describes the compound below?

A) a wax
B) a saturated triglyceride
C) a terpene
D) a prostaglandin
E) a lecithin

Question 12

Is cholesterol an example of a simple lipid or a complex lipid? Explain briefly.

Question 13

Define $\underline{\text{ lipid. }}$

Question 14

Which of the following correctly describe(s) glyceryl trimyristate?

A) an ester
B) a complex lipid
C) a triglyceride
D) a fat
E) all of the above

Question 15

Are triglycerides simple lipids? Explain.

Question 16

In the formation of a triacylglyceride, what two functional groups chemically combine?

A) carboxylic acid and an amine
B) carboxylic acid and an alcohol
C) alcohol and an aldehyde
D) alcohol and a ketone
E) two different alcohols

Question 17

Oleic acid is an example of ________ fatty acid. A molecule of oleic acid contains a single carbon-carbon double bond and ________ carbon atoms.

A) an unsaturated; 18
B) an unsaturated; 9
C) a saturated; 52
D) a saturated; 18
E) a saturated; 9

Question 18

Which of the following terms best describes the compound below? CH₃(CH₂)₇CH=CH(CH₂)₇CO₂H

A) an unsaturated fatty acid
B) a triglyceride
C) a synthetic detergent
D) a micelle
E) isoprene

Question 19

What group of lipids are esters of long-chain fatty acids and long-chain alcohols?

Question 20

Which of the following terms best describes the compound below?

CH₃(CH₂)₁₂CO₂H

A) a triglyceride
B) a fatty acid
C) a wax
D) a prostaglandin
E) a phosphatidic acid

Question 21

Which reagent below could best be used to distinguish CH₃(CH₂)₁₀CO₂H from CH₂(CH₂)₄CH=CH(CH₂)₄CO₂H?

A) NaOH, H₂O
B) Ag(NH₃)₂⁺
C) H₂Cr₂O₇
D) Br₂/CCl₄
E) NH₃

Question 22

Name the compound whose formula is CH₃(CH₂)₁₂CO₂H.

Question 23

What reagent is needed to convert CH₃(CH₂)₁₄CH₂OH to CH₃(CH₂)₁₄CHO?

Question 24

Which of the following fatty acids has the highest melting point?

A) lauric acid
B) myristic acid
C) palmitic acid
D) stearic acid
E) linoleic acid

Question 25

Why are fats more efficient sources of long-term energy than carbohydrates?

Question 26

Which best describes the lipid shown below?

A) wax
B) triglyceride
C) saturated fatty acid
D) unsaturated fatty acid
E) lecithin

Question 27

Which of the following oils has the highest percentage of saturated fatty acid?

A) herring oil
B) olive oil
C) soybean oil
D) canola oil

Question 28

Which of the following oils has the highest composition of one single fatty acid?

A) herring oil
B) olive oil
C) soybean oil
D) canola oil

Question 29

Which of the following statements correctly describe(s) the relationship between the structure of a fatty acid and its melting point?

A) Saturated fatty acids have melting points that increase gradually with their molecular weights.
B) The presence of a trans double bond in the fatty acid has a greater effect on its melting point than does the presence of a cis double bond.
C) As the number of double bonds in a fatty acid increases, its melting point decreases.
D) both A and C
E) A, B, and C

Question 30

What reagent is needed to convert CH₃(CH₂)₁₄CO₂H to CH₃(CH₂)₁₄COCl?

Question 31

What does the term $\underline{\text{ polyunsaturated }}$ mean when used to describe a triglyceride?

Question 32

Which of the following fatty acids has the lowest melting point?

A) lauric acid
B) myristic acid
C) palmitic acid
D) stearic acid
E) linoleic acid

Question 33

Two families of fatty acids called the Ω- 6 and Ω-3 fatty acids are of significant interest in the area of nutrition. Which of the following structures would be classified as an Ω-3 fatty acid?

A)

B)

C)

D)

E)

Question 34

Which best describes the lipid shown below?

A) wax
B) triglyceride
C) saturated fatty acid
D) unsaturated fatty acid
E) lecithin

Question 35

Which best describes the lipid shown below?

A) wax
B) triglyceride
C) saturated fatty acid
D) unsaturated fatty acid
E) lecithin

Question 36

Which of the following is an unsaturated fatty acid?

A) adipic acid
B) linoleic acid
C) stearic acid
D) palmitic acid
E) oxalic acid

Question 37

Which of the following oils would consume the greatest number of equivalents of hydrogen when subject to catalytic hydrogenation?

A) corn oil
B) olive oil
C) canola oil
D) linseed oil

Question 38

What reagent is needed to convert CH₃(CH₂)₁₄CO₂H to CH₃(CH₂)₁₄CH₂OH?

Question 39

Lauric acid has the formula CH₃(CH₂)₁₀CO₂H. Provide the structure of the triglyceride which was formed from three equivalents of lauric acid.

Question 40

Which of the following oils is the least polyunsaturated?

A) herring oil
B) corn oil
C) olive oil
D) soybean oil
E) canola oil

Question 41

When a vegetable oil is partially hydrogenated, how is its structure altered and how is its melting point affected?

Question 42

What are the two major organic products which result when oleic acid,
CH₃(CH₂)₇CH= CH(CH₂)₇CO₂H, is treated with ozone followed by dimethyl sulfide?

Question 43

Draw the structure of the product which results when the compound shown below is completely hydrogenated using excess H₂.

Question 44

How is a fat distinguished from an oil, (a) based on a physical property difference and (b) based on a difference in molecular structure?

Question 45

Using solely a fatty acid as your starting material, how would you synthesize a wax?

Question 46

Why and in what fashion does the presence of a double bond in a fatty acid affect its melting point relative to the system where the double bond is absent?

Question 47

Was the compound shown below more likely isolated from an animal or a plant? Explain.

Question 48

Which packs more readily into a crystal lattice, tristearin or triolein? Explain.

Question 49

How can the degree of unsaturation of an oil be gauged using a solution of bromine in carbon tetrachloride?

Question 50

Provide the structure of the major organic compound that results when palmitic acid, CH₃(CH₂)₁₄CO₂H, is heated in ethanol containing catalytic acid.

Question 51

With which of the following reagents would linoleic acid not react?

A) HBr
B) Br₂
C) O₃
D) warm, concentrated KMnO₄
E) Na₂Cr₂O₇

Question 52

Provide the structure of the major organic compound that results when palmitic acid, CH₃(CH₂)₁₄CO₂H, is heated in methanol containing catalytic acid.

Question 53

When linoleic acid is hydrogenated, what organic compound is produced and how does its melting point compare to that of linoleic acid?

Question 54

Why do most fatty acids contain an even number of carbons?

Question 55

How would you prepare CH₃(CH₂)₁₄CH₂Br from palmitic acid, CH₃(CH₂)₁₄CO₂H?

Question 56

How would you prepare CH₃(CH₂)₁₄CH₂NH₂ from palmitic acid, CH₃(CH₂)₁₄CO₂H?

Question 57

Provide the major organic product of the following reaction.

Question 58

Which of the following are omega-3 fatty acids?

A) myristic acid
B) oleic acid
C) linolenic acid
D) arachidonic acid

Question 59

What reagents would you use to prepare octadecanal from stearic acid, CH₃(CH₂)₁₆CO₂H?

Question 60

Provide the major organic product of the reaction shown below.

Question 61

Which of the following terms best describes the compound below?

A) a phospholipid
B) a cationic detergent
C) an alkaloid
D) a hard-water scum
E) a component of most lipid bilayers

Question 62

Which of the following chemical reactions could be used to distinguish between a polyunsaturated vegetable oil and a petroleum oil containing a mixture of saturated and unsaturated hydrocarbons?

A) addition of bromine in carbon tetrachloride
B) ozonolysis
C) hydrogenation
D) lipidification
E) saponification

Question 63

Which of the following terms best describes the exterior surface of a soap micelle in water?

A) hydrophobic
B) hydrophilic
C) hard
D) saponified
E) hydrogenated

Question 64

Arrange the following fatty acids in order of increasing melting point:
stearic acid, linolenic, linoleic, and oleic.

Question 65

Provide the major organic product of the following reaction sequence.

Question 66

Draw the two fatty acid structures that result from acid and base hydrolysis of a triacylglyceride and explain how they differ. (Use a core structure of 10 carbon atoms)

Question 67

Provide the structures of the major organic products which result when tristearin (shown below) is heated in aqueous solution of sodium hydroxide.

Question 68

Which of the following terms best describes the interior of a soap micelle in water?

A) hydrophobic
B) hydrophilic
C) hard
D) saponified
E) hydrogenated

Question 69

Provide the major organic product of the following reaction.

Question 70

Which of the following is an advantage of using an alkylbenzenesulfonate detergent over a common soap?

A) The alkylbenzenesulfonate detergent is uncharged.
B) The alkylbenzenesulfonate detergent has no hydrophobic region.
C) Greases are not emulsified by soaps.
D) Calcium, magnesium, and iron salts of sulfonic acids are soluble in water.
E) Sulfonates are protonated at higher pH's than are carboxylates.

Question 71

________ is the base-promoted hydrolysis of fats and oils.

Question 72

Which of the following terms best describes the compound below? CH₃(CH₂)₄CH=CHCH₂CH=CH(CH₂)₇CO₂^-Na⁺

A) a wax
B) a soap
C) a terpene
D) a lecithin
E) a prostaglandin

Question 73

What do we call a mixture of two immiscible liquids in which one liquid is dispersed throughout the other in small droplets?

Question 74

What organic compounds result when tristearin is heated in aqueous sodium hydroxide?

Question 75

Which formula best characterizes hard-water scum?

A) [CH₃(CH₂)₁₆CO₂]₂Ca
B) CH₃CH₂CH=CHCH₂CH₂CH₂CO₂H
C) CH₃(CH₂)₁₆CO₂Na
D) CH₃(CH₂)₁₆CO₂H
E) CH₃(CH₂)₁₆SO₃Na

Question 76

Provide the major organic product of the following reaction sequence.

Question 77

The sodium or potassium salt of a fatty acid is known as a ________.

Question 78

Given a single triglyceride which contains three identical and fully saturated fatty acid residues, which of the following terms accurately describe(s) it?

A) chiral
B) optically active
C) meso
D) optically inactive
E) both A and B

Question 79

Would the addition of HCl to the double bond of oleic acid, CH₃(CH₂)₇CH= CH(CH₂)₇CO₂H, occur with high regioselectivity? Explain.

Question 80

Describe the intermolecular interaction of the surface carboxylate groups of a micelle and the surrounding water.