Fluorescence spectroscopy relies on:

A. the difference in color between two samples.
B. the shift in wavelength from excitation and emission.
C. the vibrations of atoms bonded together in a molecule.
D. the atomic mass of the sample the formation of specific ions.

Correct answer is b.

Explanation:

In analytical chemistry spectroscopy employs the use of spectrometers in chemical analysis.

Fluorescence spectroscopy is a type of electromagnetic spectroscopy which analyzes the fluorescence phenomenon from a sample.

It employs using a beam of light, the UV light preferably, that excites the electrons in molecules of certain compounds and causes them to emit light.

The devices that measure fluorescence phenomenon are called fluorometers.

Fluorescence however can is an emission phenomenon where an energy transition from a higher to a lower state is accompanied by radiation.

The principle has it that only molecules in their excited forms are able to emit fluorescence; thus, they have to be brought into a state of higher energy prior to the emission phenomenon.

Hence fluorescence spectroscopy relies on the shift in wavelength from excitation and emission.

"standard molar enthalpy:

h2o ( liquid water ) : - 285.8 kj/mole

h2o ( water vapor ) : - 241.8 kj / mole.

δhrxn = - 241. 8 - ( - 285.8 )= -241.8 + 285.8 = 44.0

answer: 44.0 kj"

the product of the pressure and volume is also constant