Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

ANAL CHEM > ANAL CHEM 5 > Flashcards

ANAL CHEM 5 Flashcards

1
Q

NMR spectroscopy is used for determining structure in which of the following materials?

Radioactive materials
Insoluble chemical compounds
Liquids
Gases

A

Liquids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

NMR is the study of absorption of __________ by nuclei in a magnetic field?

Radioactive radiation
IR radiation
Radio frequency radiation
Microwaves

A

Radio frequency radiation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

NMR spectrometer provides ____________ and _____________ method of determining structure
in soluble chemical compounds.

Accurate, destructive
Accurate, non-destructive
Inaccurate, destructive
Inaccurate, non-destructive

A

Accurate, non-destructive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

NMR spectroscopy indicates the chemical nature of the __________ and spatial positions of _______

Electrons, Protons
Neutrons, electrons
Nuclei, electrons
Nuclei, neighbouring nuclei

A

Nuclei, neighbouring nuclei

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

In NMR spectroscopy, the spinning nuclei in strong magnetic field must be irradiated by which of the following?

Perpendicular and stronger field
Perpendicular and weaker field
Parallel and stronger field
Parallel and weaker field

A

Perpendicular and weaker field

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Interaction between matter and electromagnetic radiation can be observed by subjecting a substance to magnetic fields in which of the following manner?

Both fields should be stationary

Both fields should be varying

One field should be stationary and the other should be varying

It must be subjected to only one field

A

One field should be stationary and the other should be varying

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

When energy is absorbed by the sample, the absorption can be observed as a change in signal developed by which of the following components?

Amplifier
Photodetector
GM counter
Radiofrequency detector

A

Radiofrequency detector

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Which of the following are considered to be the lowest form of Electromagnetic radiation?

IR radiation
Micro waves
UV radiation
Radio waves

A

Radio waves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

The amount of energy available in radio frequency radiation is sufficient for which of the following?

Excite an atom
Vibrate an atom
Vibrate a molecule
Affect the nuclear spin of an atom

A

Affect the nuclear spin of an atom

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Nuclei having either the number of protons or neutrons as odd have _______ spin.

Integral spin
Half integral spin
Zero spin
Positive spin

A

Half integral spin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

If the number of protons or neutrons is even the spin of the nucleus will be which of the following?

Integral spin
Half integral spin
Zero spin
Positive spin

A

Zero spin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

The difference between the field necessary for resonance in the sample and in some arbitrary chosen compound is which of the following?

Field shift
Matrix effects
Chemical shift
Resonance shift

A

Chemical shift

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Chemical shift allows a chemist to obtain the idea of how atoms are joined together.

True
False

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q
  1. Elementary particles such as electrons and nucleus have the property of spin.

True
False

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q
  1. Which of the following is not a type of NMR spectrometer?

Minimal type
Maximal type
Multipurpose type
Wideline type

A

Maximal type

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q
  1. Which of the following NMR spectrometers have stressed reliability and ease of operation?

Minimal type
Maximal type
Multipurpose type
Wideline type

A

Minimal type

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Which of the following type of NMR spectrometer uses a frequency synthesizer to generate RF fields?

Minimal type
Maximal type
Multipurpose type
Wideline type

A

Multipurpose type

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

In wideline NMR spectrometers, which of the following has to be supplied to the electromagnet?

Slowly varying low voltage
Rapidly varying low voltage
Slowly varying scan voltage
Rapidly varying scan voltage

A

Slowly varying scan voltage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Which among the following NMR spectrometer is the more diverse spectrometer?

Minimal type
Maximal type
Multipurpose type
Wideline type

A

Multipurpose type

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Permanent magnet cannot be used in wideline type NMR spectrometer.

True
False

A

False

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Which of the following NMR spectrometer emphasises on high performance versatility with cost being a secondary consideration?

Minimal type
Maximal type
Multipurpose type
Wideline type

A

Multipurpose type

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Which of the following NMR spectrometer does not require power supply and cooling system?

Minimal type
Maximal type
Multipurpose type
Wideline type

A

Minimal type

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Minimal type NMR spectrometer is inexpensive.

True
False

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Which of the following is used as coolant for magnets in continuous-wave NMR spectrometer?

Water
Liquid He
Liquid Na
Heavy water

A

Water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Which of the following components are used to separate the nuclear spin energy states? RF channels Magnet Sample probe Sweep generator
Magnet
26
26. In frequency sweep method, which of the following parameters are varied continuously? Magnetic field RF signal Sample concentration Amplification factor
RF signal
27
In field sweep method, which of the following parameters are varied continuously? Magnetic field RF signal Sample concentration Amplification factor
Magnetic field
28
Which of the following statements are not true about permanent magnets? They are simple They are inexpensive They don’t require shielding They don’t require power supply
They don’t require shielding
29
Which of the following is not true of electromagnets? They are expensive They require power supply They don’t require cooling system They don’t require extensive shielding
They don’t require cooling system
30
For high resolution work the magnetic field over the entire sample volume must be maintained uniform in space and time. True False
True
31
Which of the following must not be done to maintain the magnetic field over the sample uniform in space and time? Large pole pieces need to be used Pole faces must be polished Wide pole gap must be present Magnets can be permanent or electromagnet
Wide pole gap must be present
32
The sample is contained in which of the following components? Flask Capillary tube Curvette Bore glass tube
Bore glass tube
33
The single coil probe supplies the RF radiation to the sample and also serves as a part of which of the following circuits? RF channels Magnet Detector dSweep generator
Detector
34
Nuclear induction probes’ one coil is used for signal detection. What is the function of the other coil? Sample irradiation Magnet Detector Sweep generator
Sample irradiation
35
The voltage generated by the receiver coil is small and it must be amplified. True False
True
36
The amplification required for continuous-wave NMR is of the order of which of the following? 10^1 10^2 10^3 10^5
10^5
37
Which of the following can be used instead of magnets to produce the magnetic field? Inductor Motor Generator Superconducting solenoids
Superconducting solenoids
38
How is the inhomogeneity of magnetic fields compensated? With large magnetic fields With small magnetic fields By using two or more magnets By providing required insulation
With small magnetic fields
39
Fourier transform NMR spectrometer allows NMR transitions to be observed simultaneously. True False
True
40
Fourier transform NMR spectrometer has which of the following characteristics? Increased sensitivity, long time to obtain data Decreased sensitivity, long time to obtain data Increased sensitivity, reduced time to obtain data Decreased sensitivity, reduced time to obtain data
Increased sensitivity, reduced time to obtain data
41
Which of the following cannot be done due to the multiplex advantage? Repetitive signals can be summed Repetitive signals can be averaged Increases signal to noise ratio Decreases signal to noise ratio
Decreases signal to noise ratio
42
Two coils are necessary in Fourier transform NMR spectroscopy. True False
False
43
Which of the following is the disadvantage of conventional mode of spectrometer or continuous-wave NMR spectrometer? They are unstable Maintenance is difficult High operating cost Excitation is inefficient
Excitation is inefficient
44
Which of the following must be done to improve sensitivity? Frequency sweep mode must be preferred Field sweep mode must be preferred Single channel excitation must be preferred Multichannel excitation must be preferred
Multichannel excitation must be preferred
45
Which of the following is the disadvantage of multichannel excitation? Low sensitivity Low resolution Small number of frequencies is present Uneconomical
Uneconomical
46
How can the need for array of narrow-band filters and detectors be eliminated? By using multi-channel excitation By using a detector for each frequency By reducing the number of detectors By using Fourier transform
By using Fourier transform
47
Fourier transform can be accomplished by using which of the following components? Spin decoder Detector Spectrum analyser Oscilloscope
Spectrum analyser
48
A 15.4 MHz crystal generates the _________ resonance frequency? Hydrogen Deuterium Tritium Helium
Deuterium
49
Sensitivity is the ratio of peak signal amplitude to which of the following? Time Rms noise Average noise Peak-to-peak noise
Rms noise
50
Which of the following is not an operating technique for sensitivity enhancement? Optimization of sample volume Optimization of instrumental parameters Optimization of noise Time averaging
Optimization of noise
51
Which of the following techniques do not enhance sensitivity by a factor of 10 at normal operating conditions? Optimization of sample volume Optimization of instrumental parameters Optimization of noise Time averaging
Time averaging
52
The most common spherical cells have which of the following dimensions? 4mm diameter 40mm diameter 8mm diameter 80mm diameter
4mm diameter
53
``` Better sensitivity with good resolution can be achieved by concentrating the sample inside which of the following? Sample cell Micro cell Sample tube Cylindrical tube ```
Micro cell
54
Frequency spectrum of noise occupies a band that is _________ the signal spectrum. Choose the most appropriate option. Narrow than Wider than Different from Same as
Wider than
55
Suppression of frequencies which contain no signal does which of the following? Increases S/N ratio Decreases S/N ratio S/N ratio is kept constant S/N ratio becomes 1
Increases S/N ratio
56
The amplitude of the NMR signal caused by the absorption of RF energy at the radio frequency does not depend upon the power of the RF energy applied. True False
False
57
Which of the following is not involved in signal averaging? A system to repeatedly scan the spectral region of interest Some storage device to store information A system to coherently add individual spectra Sweep generator
Sweep generator
58
In order to have a long measuring time for increasing sensitivity, it is better to have several fast scans than a single slow scan. True False
True
59
In Spin Decoupler, the output of the DC amplifier is applied to which of the following to control the power supplied to the oven heaters? Power diode Power transistor Power MOSFET Power IGBT
Power transistor
60
61. In Spin Decoupler, the difference frequency circuit provides a means of mixing two signals and a filter to recover which of the following? Low-frequency component High-frequency component Low-voltage component High-voltage component
Low-frequency component
61
Mass spectrometers are used to determine which of the following? Composition in sample Concentration of elements in sample Relative mass of atoms Properties of sample
Relative mass of atoms
62
63. Who invented mass spectrometers? J.J Thompson Goldstein Nikola Tesla Aston
J.J Thompson
63
In mass spectrometer, the sample that has to be analysed is bombarded with which of the following? Protons Electrons Neutrons Alpha particles
Electrons
64
Mass spectrometer separates ions on the basis of which of the following? Mass Charge Molecular weight Mass to charge ratio
Mass to charge ratio
65
In mass spectrometer, the ions are sorted out in which of the following ways? By accelerating them through electric field By accelerating them through magnetic field By accelerating them through electric and magnetic field By applying a high voltage
By accelerating them through electric and magnetic field
66
No two molecules will be fragmented and ionized in exactly the same manner. True False
True
67
The procedure for mass spectroscopy starts with which of the following processes? The sample is bombarded by electron beam The ions are separated by passing them into electric and magnetic field The sample is converted into gaseous state The ions are detected
The sample is converted into gaseous sta
68
In mass spectrometer, the ion currents are measured using which of the following? Scintillation counter Ion counter Electrometer tube Electric fields
Electrometer tube
69
Which of the following ions pass through the slit and reach the collecting plate? Negative ions of all masses Positive ions of all masses Negative ions of specific mass Positive ions of specific mass
Positive ions of specific mass
70
Which of the following statements is not true about mass spectrometry? Impurities of masses different from the one being analysed interferes with the result It has great sensitivity It is suitable for data storage It is suitable for library retrival
Impurities of masses different from the one being analysed interferes with the resul
71
In mass spectrometer, the sample gas is introduced into the highly evacuated spectrometer tube and it is ionised by electron beam. True False
True
72
end
end

ANAL CHEM (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions