Spectrophotometry

Question 1

Beer’s Law

Answer 1

Concentration of a substance is proportional to amount of light absorbed

Question 2

Transmittance

Answer 2

Intensity of a transmitted light beam divided by intensity of an incoming light beam

Question 3

Wavelength

Answer 3

Distance between crests measured in nm

Question 4

How do we characterize Electromagnetic Waves?

Answer 4

Frequency and Wavelength

Question 5

What range does Infrared Radiation fall in?

Answer 5

> 750 nm

Question 6

What range does visible light fall in?

Answer 6

380 and 750 nm

Question 7

What range does UV radiation fall in?

Answer 7

<380 nm

Question 8

Why is the concept of transmittance important?

Answer 8

Only transmitted light can be measured

Question 9

Percent Transmittance

Answer 9

Ratio of the light transmitted divided by the light of the sample

Question 10

What does a Spectrophotometer do?

Answer 10

Determine the concentration of the light absorbing substance in the solution

Question 11

What are the major components of a Spectrophotometer?

Answer 11

Light Source
Monochromator
Cuvette
Photodetector
Readout Device

Loud makes of Cars are pretty ratchet

Question 12

What is a Tungsten Lamp used for?

Answer 12

Visible wavelengths
Does not supply sufficient energy below 320 nm

Question 13

Why are filters important?

Answer 13

Cheap
Not precise but cheap

Question 14

What is widely used in Spectrophotometers?

Answer 14

Diffraction Gratings
Extremely accurate

Question 15

What do we need to know about a Cuvette?

Answer 15

Holds liquid samples
Can be round, square, or rectangular
Made from glass, quartz, or plastic

Question 16

Photodetector

Answer 16

Converts light into an electrical signal

Question 17

Readout Device

Answer 17

Converts light into a readable measurement