Question 1

Why is carbon-carbon splitting typically not seen in 13C NMR spectra?

Accepted Answer

Only 1% of the carbo

Question 2

How many peaks appear in the proton spin decoupled 13C NMR spectrum of the compound below?

Accepted Answer

Question 3

How many peaks appear in the proton spin decoupled 13C NMR spectrum of the compound below?

Accepted Answer

Question 4

On a 90 MHz spectrometer, calculate the frequency at which a proton absorbs if it appears at 4.20 ppm.

Accepted Answer

The answer of On a 90 MHz spectrometer, calculate the...

Question 5

Predict the number of signals expected in the proton spin decoupled 13C NMR spectrum of the compound shown below.

Accepted Answer

Question 6

Provide a structure that is consistent with the data below.
C7H14O2
IR (cm-1): 2950, 1740
1H NMR ( d): 2.3 (2H, q), 1.0 (3H, t), 0.9 (9H, s)
13C NMR (d ): 185 (s), 78 (s), 29 (t), 14 (q), 12 (q)

Accepted Answer

Question 7

Describe the number of signals and their splitting in the 1H NMR spectrum of (CH3)2CHOCH3.

Accepted Answer

A)  3 signals: 2 doublets and a septet 
B)  2 signals: a doublet and a septet 
C)  3 signals: a doublet, a quartet, and a septet 
D)  4 signals: 2 doublets, a singlet, and a septet 
E)  3 signals: a singlet, a doublet, and a septet 
A)  3 signals: 2 doublets and a septet 
B)  2 signals: a doublet and a septet 
C)  3 signals: a doublet, a quartet, and a septet 
D)  4 signals: 2 doublets, a singlet, and a septet 
E)  3 signals: a singlet, a doublet, and a septet

Question 8

What three-word term is abbreviated NMR?

Accepted Answer

nuclear ma

Question 9

How many peaks appear in the proton spin decoupled 13C NMR spectrum of the compound below?

Accepted Answer

Question 10

Why is carbon-hydrogen splitting not a major part of 1H NMR spectra?

Accepted Answer

Most of the carbons

Question 11

Predict the number of signals expected in the proton spin decoupled 13C NMR spectrum of o-diethylbenzene (1,2-diethylbenzene).

Accepted Answer

Question 12

Use the structure below to state the relationship between the indicated protons as equivalent, enantiotopic, diastereotopic, or unrelated.   
Ha & Hb:
Ha & Hc:
Hb & Hc:

Accepted Answer

H_a & H_b: Diastereotopi

Question 13

You have a sample and its 1H NMR spectrum. You know your sample contains O atoms but not N atoms, and you suspect that your sample may be an alcohol. What common spectroscopic technique might you use to confirm your suspicion?

Accepted Answer

Take an IR spectrum and look f

Question 14

The 1H NMR spectrum of ethanol is acquired and the hydroxyl signal appears as a singlet instead of a triplet. Offer an explanation.

Accepted Answer

A fast exchange of the hydroxy

Question 15

What information does the intensity (integration) of a signal in the 1H NMR spectrum give you?

Accepted Answer

A)  how many different types of protons are present 
B)  the electronic structure of the molecule close to each type of proton 
C)  how many protons of each type are present 
D)  how many neighboring protons are present 
A)  how many different types of protons are present 
B)  the electronic structure of the molecule close to each type of proton 
C)  how many protons of each type are present 
D)  how many neighboring protons are present

Question 16

A nucleus with an ________ atomic number or an ________ mass number has a nuclear spin that can be observed by the NMR spectrometer.

Accepted Answer

A)  even; odd 
B)  odd; even 
C)  odd; odd 
D)  even; even 
A)  even; odd 
B)  odd; even 
C)  odd; odd 
D)  even; even

Question 17

An NMR spectrometer that operates at a frequency of 60 MHz for 13C NMR spectra, operates at what frequency for 1H NMR spectra?

Accepted Answer

A)  15 MHz 
B)  30 MHz 
C)  60 MHz 
D)  120 MHz 
E)  240 MHz 
A)  15 MHz 
B)  30 MHz 
C)  60 MHz 
D)  120 MHz 
E)  240 MHz

Question 18

Deduce the identity of the following compound from the spectral data given.
C8H10: 1H NMR, δ 1.20 (3H, triplet), 2.60 (2H, quartet), 7.12 (5H, singlet) (ppm); IR, 3050, 2970,   
MS, m/z 91

Accepted Answer

Question 19

What 1H NMR spectral data is expected for the compound shown?

Accepted Answer

A)  3.8 (1H, septet), 2.1 (3H, s), 1.0 (6H, d) 
B)  3.8 (1H, septet), 3.3 (3H, s), 1.0 (6H, d) 
C)  3.3 (3H, s), 2.6 (3H, septet), 1.0 (6H, d) 
D)  2.6 (1H, septet), 2.1 (3H, s), 1.0 (6H, d) 
A)  3.8 (1H, septet), 2.1 (3H, s), 1.0 (6H, d) 
B)  3.8 (1H, septet), 3.3 (3H, s), 1.0 (6H, d) 
C)  3.3 (3H, s), 2.6 (3H, septet), 1.0 (6H, d) 
D)  2.6 (1H, septet), 2.1 (3H, s), 1.0 (6H, d)

Question 20

How many peaks appear in the proton spin decoupled 13C NMR spectrum of the compound below?

Accepted Answer

Exam 13: Nuclear Magnetic Resonance Spectroscopy

Why is carbon-carbon splitting typically not seen in 13C NMR spectra?

How many peaks appear in the proton spin decoupled 13C NMR spectrum of the compound below?

How many peaks appear in the proton spin decoupled 13C NMR spectrum of the compound below?

On a 90 MHz spectrometer, calculate the frequency at which a proton absorbs if it appears at 4.20 ppm.

Predict the number of signals expected in the proton spin decoupled 13C NMR spectrum of the compound shown below.

Provide a structure that is consistent with the data below. C7H14O2 IR (cm-1): 2950, 1740 1H NMR ( d): 2.3 (2H, q), 1.0 (3H, t), 0.9 (9H, s) 13C NMR (d ): 185 (s), 78 (s), 29 (t), 14 (q), 12 (q)

Describe the number of signals and their splitting in the 1H NMR spectrum of (CH3)2CHOCH3.

What three-word term is abbreviated NMR?

How many peaks appear in the proton spin decoupled 13C NMR spectrum of the compound below?

Why is carbon-hydrogen splitting not a major part of 1H NMR spectra?

Predict the number of signals expected in the proton spin decoupled 13C NMR spectrum of o-diethylbenzene (1,2-diethylbenzene).

Use the structure below to state the relationship between the indicated protons as equivalent, enantiotopic, diastereotopic, or unrelated. Ha & Hb: Ha & Hc: Hb & Hc:

You have a sample and its 1H NMR spectrum. You know your sample contains O atoms but not N atoms, and you suspect that your sample may be an alcohol. What common spectroscopic technique might you use to confirm your suspicion?

The 1H NMR spectrum of ethanol is acquired and the hydroxyl signal appears as a singlet instead of a triplet. Offer an explanation.

What information does the intensity (integration) of a signal in the 1H NMR spectrum give you?

A nucleus with an ________ atomic number or an ________ mass number has a nuclear spin that can be observed by the NMR spectrometer.

An NMR spectrometer that operates at a frequency of 60 MHz for 13C NMR spectra, operates at what frequency for 1H NMR spectra?

Deduce the identity of the following compound from the spectral data given. C8H10: 1H NMR, δ 1.20 (3H, triplet), 2.60 (2H, quartet), 7.12 (5H, singlet) (ppm); IR, 3050, 2970, MS, m/z 91

What 1H NMR spectral data is expected for the compound shown?

How many peaks appear in the proton spin decoupled 13C NMR spectrum of the compound below?

Structure and Bonding

Acids and Bases; Functional Groups

Structure and Stereochemistry of Alkanes

The Study of Chemical Reactions

Stereochemistry

Alkyl Halides; Nucleophilic Substitution

Structure and Synthesis of Alkenes; Elimination

Reactions of Alkenes

Structure and Synthesis of Alcohols

Reactions of Alcohols

Infrared Spectroscopy and Mass Spectrometry

Ethers, Epoxides, and Thioethers

Conjugated Systems, Orbital Symmetry, and Ultraviolet Spectroscopy

Aromatic Compounds

Reactions of Aromatic Compounds

Ketones and Aldehydes

Amines

Carboxylic Acids

Carboxylic Acid Derivatives

Condensations and Alpha Substitutions of Carboxyl Compounds

Carbohydrates and Nucleic Acids

Amino Acids, Peptides, and Proteins

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Why is carbon-carbon splitting typically not seen in ¹³C NMR spectra?

How many peaks appear in the proton spin decoupled ¹³C NMR spectrum of the compound below?

How many peaks appear in the proton spin decoupled ¹³C NMR spectrum of the compound below?

Predict the number of signals expected in the proton spin decoupled ¹³C NMR spectrum of the compound shown below.

Provide a structure that is consistent with the data below. C₇H₁₄O₂ IR (cm^-1): 2950, 1740 ¹H NMR ( d): 2.3 (2H, q), 1.0 (3H, t), 0.9 (9H, s) ¹³C NMR (d ): 185 (s), 78 (s), 29 (t), 14 (q), 12 (q)

Describe the number of signals and their splitting in the ¹H NMR spectrum of (CH₃)₂CHOCH₃.

How many peaks appear in the proton spin decoupled ¹³C NMR spectrum of the compound below?

Why is carbon-hydrogen splitting not a major part of ¹H NMR spectra?

Predict the number of signals expected in the proton spin decoupled ¹³C NMR spectrum of o-diethylbenzene (1,2-diethylbenzene).

Use the structure below to state the relationship between the indicated protons as equivalent, enantiotopic, diastereotopic, or unrelated. H_a & H_b: H_a & H_c: H_b & H_c:

You have a sample and its ¹H NMR spectrum. You know your sample contains O atoms but not N atoms, and you suspect that your sample may be an alcohol. What common spectroscopic technique might you use to confirm your suspicion?

The ¹H NMR spectrum of ethanol is acquired and the hydroxyl signal appears as a singlet instead of a triplet. Offer an explanation.

What information does the intensity (integration) of a signal in the ¹H NMR spectrum give you?

A nucleus with an atomic number or an mass number has a nuclear spin that can be observed by the NMR spectrometer.

An NMR spectrometer that operates at a frequency of 60 MHz for ¹³C NMR spectra, operates at what frequency for ¹H NMR spectra?

Deduce the identity of the following compound from the spectral data given. C₈H₁₀: ¹H NMR, δ 1.20 (3H, triplet), 2.60 (2H, quartet), 7.12 (5H, singlet) (ppm); IR, 3050, 2970, MS, m/z 91

What ¹H NMR spectral data is expected for the compound shown?

How many peaks appear in the proton spin decoupled ¹³C NMR spectrum of the compound below?