Nagwa uses cookies to ensure you get the best experience on our website. Learn more about our Privacy Policy.

Lesson: Generating NMR Spectra

In this lesson, we will learn how to generate an applied magnetic field and how an RF pulse can be used to produce NMR spectra from spin-active nuclei.

Worksheet • 7 Questions

Q1:

The electromagnetic radiation used for NMR spectroscopy falls in which region?

  • ARadio wave
  • BUltraviolet
  • CMicrowave
  • DGamma ray
  • EX-ray

Q2:

NMR involves what kind of analysis?

  • AUsing radio waves to detect nuclei present in a molecule (such as H or C ) and based on extensive data bases of “chemical shifts,” determine what each type is bonded to.
  • BSpinning nuclei in such a way that they can be seen with infrared radiation and functional groups determined from the frequency.
  • CUsing high energy beams to excite the electrons so they can be detected by magnetic field fluctuations.
  • DMagnetizing the molecules so they can be separated by traveling through a vacuum down a long tube surrounded by static magnets.

Q3:

Which of the following molecular properties is affected by the measurement of an NMR spectrum?

  • ANuclear spin
  • BMolecular rotations
  • CValence electrons
  • DMolecular vibrations
  • ECore electrons

Q4:

In which units are NMR chemical shifts usually reported?

  • Appm
  • BHz
  • Cnm
  • DMHz

Q5:

In a NMR experiment, a radio frequency (RF) signal is applied to the sample, in addition to the magnetic field. What happens to the spins of the sample?

  • AThe RF will flip the spin, inducing a spin transition to a slightly higher-energy state.
  • BThe RF will force all spins to align opposite to the magnetic field.
  • CThe RF will force all spins to align with the magnetic field.
  • DThe RF will force all spins to assume a random orientation.

Q6:

In a NMR experiment, an external magnetic field is applied to the sample. What happens to the protons in the sample?

  • ASome protons align with the field and some align opposite to it.
  • BAll protons align opposite to the field.
  • CAll protons assume a random orientation.
  • DAll protons align with the field.

Q7:

In NMR spectroscopy, what happens to the chemical shift and resonance frequency of a compound when the spectrometer frequency changes?

  • AThe chemical shift remains constant; the resonance frequency changes.
  • BThere is no way to predict the effect.
  • CThe chemical shift and resonance frequency also change.
  • DThe chemical shift and resonance frequency remain constant.
  • EThe chemical shift changes; the resonance frequency remains constant.
Preview

Related Lessons