Chem Spectrophotometry

Front 1

Define the Electromagnetic Radiation Spectrum

Back 1

form of observed energy

Front 2

State the electromagnetic radiation spectrum color order:

Back 2

Red
Orange
Yellow
Green
Blue
Indigo
Violet

Front 3

What wavelength is visible light in?

Back 3

10 -6

Front 4

Increased wavelength = ?energy & ?frequency

Back 4

decreased energy and frequency

Front 5

What is produced from electromagnetic radiation + a substance?

Back 5

Energy

Front 6

Define Absorbed:
Define Transmitted:

Back 6

Absorbed: unseen light
Transmitted: light that is seen

Front 7

How are absorbance and transmittance related?

Back 7

adversly related
increased absorbance = decreased transmittance

Front 8

What transmittance does black have?

Back 8

0

Front 9

What is the formula for Absorbance?

Back 9

2- log (%trans)

Front 10

State Beers Law:

Back 10

A (absorbance) = a (absorptivity) x b (sample length) x c (conc)

Front 11

How are absorbance and concentration related?

Back 11

they are directly related
increased absorbance = increased concen.

Front 12

What factors are always constant in Beer's Law?

Back 12

a (absorptivity)
b (sample length)

Front 13

Define extrapolation:

Back 13

results that are above linearity

Front 14

Name 5 limitations for Beer's Law:

Back 14

1. non diluted specimens
2. stray light
3. non- monochromatic light
4. measuring cell irregularity
5. it cannot gaurantee specific analyte is the only substance measured

Front 15

Name the 5 parts of the spetrophotometer and describe each:

Back 15

light source (white light, tungsten/halogen)
monochromator (selects for 1 wavelength)
cuvet (optically pure measuring cell)
photocell detector (converts light into electrical energy)
recorder

Front 16

What is the purpose of a spectrophotometer?

Back 16

to measure absorbance of a substance

Front 17

name the 3 types of monochromators:

Back 17

simple
composite
interference (most popular, narrow bandpass)

Front 18

Name the 2 types of photocell detectors:

Back 18

photodiodes
photomultiplier tubes (most sensitive)

Front 19

Name 3 ways to check the QA of the spectrophotometer:

Back 19

Photometric accuracy
Wavelength check (spectral peaks)
Stray Light check

Front 20

Name the 5 types of spectrophotometry:

Back 20

Basic
Atomic Absorption
Flame Emission
Florescence
Luminescence

Front 21

Name the two types of concentration measuring devices that use light scattering technique?

Back 21

Nephrometry
Turbidometry

Front 22

Atomic Absorption Spectrophotometry:

Elements used?
Elements used must be?
What does the flame act as?

Back 22

Lead, Copper, Lithium

Elements must be reduced into a neutral state and vaporized

Flame is the measuring cell

Front 23

What two types of Spectrophotometry use light emission principles?

Back 23

Flame Emission
Luminescence

Front 24

Flame Emission Photometry:

The flame works as the?
Lacks what value for the Beer law?
The Emmission is equal to the:

Back 24

Flame is the light source

No "b" value (sample length)

Emission = concentration

Front 25

Flourescence:

What is used to excite the atoms?
What is common with the atoms during excitation?
What substance is used?
WHat is this technique sensitive too?

Back 25

Electromagnetic radiation

The Atoms lose and emit energy when excited

Flourophore

sensitive to pH & temp

Front 26

Luminescence:

Uses what principle and technique?
What are the 2 types?
What is used to measure light emission/ absorption?

Back 26

Light Emission Principle using enzyme/chemical reactions

Chemi-luminescence
Bio-Luminescence

Scintillation counter for cps of absorption