Spectroscopic techniques

Which region of the electromagnetic spectrum has the longest wavelength?

• ultraviolet

• infrared

• radio

• visible

It is used to identify the bonds in a molecule.

• Infrared spectroscopy

• mass spectroscopy

• x ray crystallography

• NMR

In a mass spectrum, the fragment with the highest mass belongs to the _________.

• [COOH]+

• whole molecule

• most abundant ion

• molecular ion

This fragment has a mass of 15.

• OH-

• H₂O

• CH₃

• CH₃+

It causes a bond to stretch or bend.

• radio waves

• microwaves

• infrared radiation

• X rays

Which part of the EM spectrum is used in nuclear magnetic resonance spectroscopy?

What information can be obtained from the number of peaks in the H NMR spectrum of a compound?

• The number of different chemical environments occupied by the protons in one molecule of the compound.

• The number of hydrogen atoms in one molecule of the compound.

• The number of different functional groups in one molecule of the compound

• the number of carbon atoms in one molecule of the compound

It is the standard used in nuclear magnetic resonance spectroscopy.

• methyl propane

• tetramethylsilane

• benzene

• sulfuric acid

The H NMR spectrum of a compound exhibits three major peaks and the splitting patterns below.

Chemical shift/ppm Peak area
1.0         --------     3
2.0         --------     3
2.3         --------     2

• CH3CH2CH3

• CH3CH2CHO

• CH3CH2COCH3

• CH3CH2CH2CH2CH3

This technique gives information about the functional groups present in the compound.

• Mass spectroscopy

• Infrared radiation

• proton nuclear magnetic resonance

• index of hydrogen deficiency