Spectrophotometry

Question 1

What is the principle of spectrophotometry?
(Lecture’s principle)
(2)

Answer 1

Spectroscopy makes use of the fact that different substances absorb or emit electromagnetic radiation in different ways

These differences are observed in the spectra of substances by using a spectrophotometer

Question 2

What is a spectrometer?

Answer 2

Its a photometer (a device for measuring light intensity) that can measure intensity as a function of the colour, or more specifically, the wavelength of light

Question 3

What is a spectroscopy?

Answer 3

Spectroscopy is a type of chemical analysis done by shining light on a sample to determine what is inside

Question 4

How do biochemists make use of spectrometry?

Answer 4

Biochemists measure the absorbance or transmittance of a sample

Question 5

What is absorbance?

Answer 5

How much light is absorbed by the sample

Question 6

What is transmittance?

Answer 6

How much light passes through the sample

Question 7

List the parts of the spectrophotometer.

4

Answer 7

A light source

A holder for the sample

A diffraction grating or monochromator to separate the different wavelengths of light

A detector

Question 8

What is a monochromator/diffraction grating?

Answer 8

An optical device that transmits a mechanically selectable narrow band of wavelengths of light or other radiation chosen from a wider range of wavelengths available at the input.

Question 9

What is absorbance?

Answer 9

A quantitative measure of the extent to which a compound absorbs ultraviolet-visible radiation at a particular wavelength

Question 10

What is transmittance?

Answer 10

A quantitative measure of the extent to which a compound absorbs ultraviolet-visible radiation at particular wavelength

Question 11

What does Beer Lambert’s Law tell us?

Answer 11

Beer’s Law tells us that if a solute absorbs light of a
particular wavelength, the absorbance is directly
proportional to the concentration of substance in
solution.