Carbon NMR

What is the primary use of Carbon-13 NMR in scientific research?

• To determine the molecular weight of a compound

• To identify the functional groups in a molecule

• To analyze the carbon skeleton of organic compounds

• To measure the acidity of a solution

Tags

NGSS.HS-LS1-6

In Carbon-13 NMR, what does the chemical shift indicate?

• The number of carbon atoms in a molecule

• The environment surrounding a carbon atom

• The molecular weight of the compound

• The temperature of the sample

Which of the following is a common solvent used in Carbon-13 NMR spectroscopy?

• Water

• Chloroform-d

• Ethanol

• Acetone

Tags

NGSS.HS-PS4-3

What is the typical range of chemical shifts for Carbon-13 NMR?

• 0-10 ppm

• 10-100 ppm

• 0-200 ppm

• 200-400 ppm

Why is Carbon-13 used in NMR instead of Carbon-12?

• Carbon-13 is more abundant

• Carbon-13 has a nuclear spin

• Carbon-12 is radioactive

• Carbon-12 is too heavy

What is the natural abundance of Carbon-13 isotope?

• 1.1%

• 10%

• 50%

• 99%

In a Carbon-13 NMR spectrum, what does a peak represent?

• A single carbon atom

• A group of equivalent carbon atoms

• The entire molecule

• The solvent used

What is the role of the magnetic field in Carbon-13 NMR?

• To heat the sample

• To align the nuclear spins

• To ionize the sample

• To cool the sample

Which of the following factors can affect the chemical shift in Carbon-13 NMR?

• Temperature

• Pressure

• Magnetic field strength

• All of the above

What is the purpose of using a deuterated solvent in Carbon-13 NMR?

• To increase the resolution

• To reduce the background signal

• To enhance the signal of carbon atoms

• To stabilize the sample