Question 1

Which has a lower characteristic stretching frequency,the C   O bond or the C-O bond? Explain briefly.

Accepted Answer

Stronger bonds are generally s

Question 2

When cyclopentanol is treated with chromic acid,the alcohol is oxidized to cyclopentanone.Which m/z peak is expected to be the base peak of cyclopentanone?

Accepted Answer

A) 55 
B) 43 
C) 29 
D) 84 
E) 85 
A) 55 
B) 43 
C) 29 
D) 84 
E) 85

Question 3

Which of the following characterizes the unusually intense peak of alkyl chlorides in MS spectrometry?

Accepted Answer

A) M + 1 peak 
B) M + 2 peak 
C) base peak 
D) parent peak 
E) none of the above 
A) M + 1 peak 
B) M + 2 peak 
C) base peak 
D) parent peak 
E) none of the above

Question 4

Which of the following statements best describes the meaning of the following species [CH3CH2CH3] ∙ + ?

Accepted Answer

A) It is the molecular ion of propane. 
B) It is the parent ion of propane. 
C) It is the radical cation of propane. 
D) The m/z value is 44. 
E) all of the above 
A) It is the molecular ion of propane. 
B) It is the parent ion of propane. 
C) It is the radical cation of propane. 
D) The m/z value is 44. 
E) all of the above

Question 5

Which of the following compounds has a vibration that is infrared inactive?

Accepted Answer

A) CH3-C   C-H 
B) H2O 
C)    
D) CO2 
E) CO 
A) CH3-C   C-H 
B) H2O 
C)    
D) CO2 
E) CO

Question 6

Which of the following m/z values is the molecular ion for 2-butanone?

Accepted Answer

A) 15 
B) 29 
C) 43 
D) 57 
E) 72 
A) 15 
B) 29 
C) 43 
D) 57 
E) 72

Question 7

The pKa of a compound whose acidic or basic form absorbs UV or visible light can be determined spectroscopically since

Accepted Answer

A) lmax always decreases as acidic form is converted to basic. 
B) the pKa is the same as the pH at which half of the total absorbance increase occurs. 
C) absorbance of the basic form is always twice that of the acidic form. 
D) absorbance of the acidic form is always twice that of the basic form. 
E) delocalization always leads to a decrease in acidity. 
A) lmax always decreases as acidic form is converted to basic. 
B) the pKa is the same as the pH at which half of the total absorbance increase occurs. 
C) absorbance of the basic form is always twice that of the acidic form. 
D) absorbance of the acidic form is always twice that of the basic form. 
E) delocalization always leads to a decrease in acidity.

Question 8

Describe the fate of a molecule from introduction to detection in a mass spectrometer.

Accepted Answer

Upon introduction,sample molecules are i

Question 9

Give the m/z ratio of the molecular ion in the mass spectrum of 1-butanol.

Accepted Answer

The answer of Give the m/z ratio of the molecular...

Question 10

In the infrared spectrum,a compound of formula C4H8O gave an absorption band at 1720 cm-1,but no bands at 2720 - 2830 and 3400 cm-1.What is the compound?

Accepted Answer

A) 2-butanone 
B) butanal 
C) cis-2-butenol 
D) trans-2-butenol 
E) 1-butenol 
A) 2-butanone 
B) butanal 
C) cis-2-butenol 
D) trans-2-butenol 
E) 1-butenol

Question 11

Show the m/z values of the molecular ion and 5 likely fragments for the compound ethyl ether,
CH3CH2OCH2CH3

Accepted Answer

74,59,45,4

Question 12

Identify the compound with the shortest λmax in an UV spectrum.

Accepted Answer

A) 1-decene 
B) 1,3-decadiene 
C) 1,3,5-decatriene 
D) 1,4-decadiene 
E) 1,3,5,7-decatetraene 
A) 1-decene 
B) 1,3-decadiene 
C) 1,3,5-decatriene 
D) 1,4-decadiene 
E) 1,3,5,7-decatetraene

Question 13

A mixture of two compounds give absorption bands at 1470,1595,1700,2720,and 2740 cm-1.What compounds are present?

Accepted Answer

A) aldehyde + benzene 
B) ketone + benzene 
C) ester + benzene 
D) carboxylic acid + benzene 
E) anhydrice + benzene 
A) aldehyde + benzene 
B) ketone + benzene 
C) ester + benzene 
D) carboxylic acid + benzene 
E) anhydrice + benzene

Question 14

Give the m/z ratio that corresponds to the molecular ion in the mass spectrum of 2-pentanone.

Accepted Answer

A) 28 
B) 43 
C) 58 
D) 71 
E) 86 
A) 28 
B) 43 
C) 58 
D) 71 
E) 86

Question 15

Which of the following compounds exhibits the pattern of m/z values shown below? 41,43,57,87,101,116

Accepted Answer

A) propylbromide 
B) isopropyl bromide 
C) sec-butyl isopropyl ether 
D) 2-hexanol 
E) 2-butanone 
A) propylbromide 
B) isopropyl bromide 
C) sec-butyl isopropyl ether 
D) 2-hexanol 
E) 2-butanone

Question 16

Arrange the following regions of the electromagnetic spectrum in order of decreasing wavelength: microwaves,visible light,ultraviolet light,infrared radiation,X-rays.

Accepted Answer

microwaves > infrare

Question 17

Which of the following are considered to be bending (in-plane)vibrations?

Accepted Answer

A) scissoring and wagging 
B) scissoring and twisting 
C) rocking and wagging 
D) rocking and twisting 
E) scissoring and rocking 
A) scissoring and wagging 
B) scissoring and twisting 
C) rocking and wagging 
D) rocking and twisting 
E) scissoring and rocking

Question 18

Which molecule below has a significant band in the IR at 3300 cm-1 (medium and sharp)?

Accepted Answer

A) 1-pentene 
B) cyclohexane 
C) 2-heptyne 
D) 1-pentyne 
E) diethyl ether 
A) 1-pentene 
B) cyclohexane 
C) 2-heptyne 
D) 1-pentyne 
E) diethyl ether

Question 19

An acylium ion is often produced as a fragment in the MS of which of the following class of organic compounds?

Accepted Answer

A) ketones 
B) ethers 
C) alkyl halides 
D) alcohols 
E) peroxides 
A) ketones 
B) ethers 
C) alkyl halides 
D) alcohols 
E) peroxides

Question 20

Which of the following solvents is best used in infrared spectroscopy?

Accepted Answer

A) I 
B) II 
C) III 
D) IV 
E) V 
A) I 
B) II 
C) III 
D) IV 
E) V

Exam 13: Mass Spectrometry,infrared Spectroscopy,and Uvvis Spectroscopy

Which has a lower characteristic stretching frequency,the C O bond or the C-O bond? Explain briefly.

When cyclopentanol is treated with chromic acid,the alcohol is oxidized to cyclopentanone.Which m/z peak is expected to be the base peak of cyclopentanone?

Which of the following characterizes the unusually intense peak of alkyl chlorides in MS spectrometry?

Which of the following statements best describes the meaning of the following species [CH3CH2CH3] ∙ + ?

Which of the following compounds has a vibration that is infrared inactive?

Which of the following m/z values is the molecular ion for 2-butanone?

The pKa of a compound whose acidic or basic form absorbs UV or visible light can be determined spectroscopically since

Describe the fate of a molecule from introduction to detection in a mass spectrometer.

Give the m/z ratio of the molecular ion in the mass spectrum of 1-butanol.

In the infrared spectrum,a compound of formula C4H8O gave an absorption band at 1720 cm-1,but no bands at 2720 - 2830 and 3400 cm-1.What is the compound?

Show the m/z values of the molecular ion and 5 likely fragments for the compound ethyl ether, CH3CH2OCH2CH3

Identify the compound with the shortest λmax in an UV spectrum.

A mixture of two compounds give absorption bands at 1470,1595,1700,2720,and 2740 cm-1.What compounds are present?

Give the m/z ratio that corresponds to the molecular ion in the mass spectrum of 2-pentanone.

Which of the following compounds exhibits the pattern of m/z values shown below? 41,43,57,87,101,116

Arrange the following regions of the electromagnetic spectrum in order of decreasing wavelength: microwaves,visible light,ultraviolet light,infrared radiation,X-rays.

Which of the following are considered to be bending (in-plane)vibrations?

Which molecule below has a significant band in the IR at 3300 cm-1 (medium and sharp)?

An acylium ion is often produced as a fragment in the MS of which of the following class of organic compounds?

Which of the following solvents is best used in infrared spectroscopy?

Remembering General Chemistry: Electronic Structure and Bonding

Acids and Bases: Central to Understanding Organic Chemistry

An Introduction to Organic Compounds: Nomenclature, physical Properties, and Structure

Isomers: the Arrangement of Atoms in Space

Alkenes: Structure,nomenclature,and an Introduction to Reactivity - Thermodynamics and Kinetics

The Reactions of Alkenes - the Stereochemistry of Addition Reactions

The Reactions of Alkynes - Introduction to Multistep Synthesis

Delocalized Electrons: Their Effect on Stability, pka, and the Products of a Reaction - Aromaticity and Electronic Effects: an Introduction to the Reactions of Benzene

Substitution and Elimination Reactions of Alkyl Halides

Reactions of Alcohols, ethers, epoxides, amines and Sulfur-Containing Compounds

Organometallic Compounds

Radicals

Nmr Spectroscopy

Reactions of Carboxylic Acids and Carboxylic Acid Derivatives

Reactions of Aldehydes and Ketones

Reactions at the Α-Carbon

Reactions of Benzene and Substituted Benzenes

More About Amines - Reactions of Heterocylic Compounds

The Organic Chemistry of Carbohydrates

Amino Acids,peptides,and Proteins

Catalysis in Organic Reactions and in Enzymatic Reactions

The Organic Chemistry of the Coenzymes, compounds Derived From Vitamins

The Organic Chemistry of the Metabolic Pathways

The Organic Chemistry of Lipids

The Chemistry of the Nucleic Acids

Synthetic Polymers

Pericyclic Reactions

Filters

Which of the following statements best describes the meaning of the following species [CH₃CH₂CH₃] ∙ + ?

The pK_a of a compound whose acidic or basic form absorbs UV or visible light can be determined spectroscopically since

In the infrared spectrum,a compound of formula C₄H₈O gave an absorption band at 1720 cm^-1,but no bands at 2720 - 2830 and 3400 cm^-1.What is the compound?

Show the m/z values of the molecular ion and 5 likely fragments for the compound ethyl ether, CH₃CH₂OCH₂CH₃

Identify the compound with the shortest λ_max in an UV spectrum.

A mixture of two compounds give absorption bands at 1470,1595,1700,2720,and 2740 cm^-1.What compounds are present?

Which molecule below has a significant band in the IR at 3300 cm^-1 (medium and sharp)?