University of Florida CHM 2210 NMR Spectroscopy || Possible
Questions Accurately Answered.
It is used to determine... correct answers Molecular structure, how individual atoms are
connected to each other
Involves the study of... correct answers The interaction b/w electromagnetic radiation and the
nuclei of atoms
Nuclear spin correct answers When a nucleus has an odd number of protons and/or neutrons,
which can be probed by NMR spec.
A spinning proton is a rotating sphere of charge that generates a magnetic field (magnetic
moment)
Alpha spin state correct answers When the magnetic moment of a proton and an external
magnetic field line up.
When exposed to electromagnetic radiation, the nucleus can undergo absorption if the energy of
the photon is equivalent to the energy gap. The absorption causes the nucleus to flip to the beta
state, and the nucleus is said to be in resonance
Beta spin state correct answers When the magnetic field of a proton goes against an external
magnetic field
Diamagnetism correct answers The electron field in the presence of an external magnetic field
produces a local (induced) magnetic field that opposes the external magnetic field.
This effect allows all protons to absorb different amounts of rf radiation
Shielded correct answers A nucleus whose chemical shift is decreased, feels weaker magnetic
field due to the addition of electron density, magnetic induction, etc. in neighboring atoms or
groups.
The proton is said to be shielded by the electrons
, Deshielded correct answers A nucleus whose chemical shift is increased, feels stronger magnetic
field due to the removal of electron density, magnetic induction, etc. in neighboring atoms or
groups
Energy gap correct answers Produced by magnetic field and source of rf radiation.
Increases with increasing magnetic field strength, and allows nucleus to absorb rf radiation
Range of frequencies used... correct answers Depends on strength of magnetic field
FT-NMR correct answers Sample is irradiated with a short pulse that covers the entire range of fr
frequencies, exciting all protons simultaneously and return to their original spin states. This
decay allows the proton to emit energy in their own particular way generating an electrical
impulse over a receiver coil (records FID)
Location of signal... correct answers Indicates the electronic environment of the protons giving
rise to the signal
Area underneath the signal... correct answers Indicates the # of protons giving rise to the signal
Shape of the signal... correct answers Indicates the # of neighboring protons
Number of signals... correct answers Indicates the # of different kinds of protons in different
electronic environments
Chemically equivalent correct answers Protons that occupy identical electronic environments,
producing only one signal.
Determined if they can be interchanged by either rotational or reflectional symmetry.
Homotopic correct answers Protons who are chemically equivalent
Questions Accurately Answered.
It is used to determine... correct answers Molecular structure, how individual atoms are
connected to each other
Involves the study of... correct answers The interaction b/w electromagnetic radiation and the
nuclei of atoms
Nuclear spin correct answers When a nucleus has an odd number of protons and/or neutrons,
which can be probed by NMR spec.
A spinning proton is a rotating sphere of charge that generates a magnetic field (magnetic
moment)
Alpha spin state correct answers When the magnetic moment of a proton and an external
magnetic field line up.
When exposed to electromagnetic radiation, the nucleus can undergo absorption if the energy of
the photon is equivalent to the energy gap. The absorption causes the nucleus to flip to the beta
state, and the nucleus is said to be in resonance
Beta spin state correct answers When the magnetic field of a proton goes against an external
magnetic field
Diamagnetism correct answers The electron field in the presence of an external magnetic field
produces a local (induced) magnetic field that opposes the external magnetic field.
This effect allows all protons to absorb different amounts of rf radiation
Shielded correct answers A nucleus whose chemical shift is decreased, feels weaker magnetic
field due to the addition of electron density, magnetic induction, etc. in neighboring atoms or
groups.
The proton is said to be shielded by the electrons
, Deshielded correct answers A nucleus whose chemical shift is increased, feels stronger magnetic
field due to the removal of electron density, magnetic induction, etc. in neighboring atoms or
groups
Energy gap correct answers Produced by magnetic field and source of rf radiation.
Increases with increasing magnetic field strength, and allows nucleus to absorb rf radiation
Range of frequencies used... correct answers Depends on strength of magnetic field
FT-NMR correct answers Sample is irradiated with a short pulse that covers the entire range of fr
frequencies, exciting all protons simultaneously and return to their original spin states. This
decay allows the proton to emit energy in their own particular way generating an electrical
impulse over a receiver coil (records FID)
Location of signal... correct answers Indicates the electronic environment of the protons giving
rise to the signal
Area underneath the signal... correct answers Indicates the # of protons giving rise to the signal
Shape of the signal... correct answers Indicates the # of neighboring protons
Number of signals... correct answers Indicates the # of different kinds of protons in different
electronic environments
Chemically equivalent correct answers Protons that occupy identical electronic environments,
producing only one signal.
Determined if they can be interchanged by either rotational or reflectional symmetry.
Homotopic correct answers Protons who are chemically equivalent
