wk 1 - spectrophotometry Flashcards
A —————— is used to provide a source of light at certain energy, ———–, and to measure the quantity of light that is absorbed by the sample.
a) Monochromator, spectrophotometer
b) Polychromator, wavelength
c) Spectrophotometer, wavelength
d) Wavelength, spectrophotometer
A Spectrophotometer is used to provide a source of light at certain energy, wavelength, and to measure the quantity of light that is absorbed by the sample.
4) A —————— is either a prism or a diffraction grating that separates the white light into all colours of the visible spectrum
A monochrometer is either a prism or a diffraction grating that separates the white light into all colours of the visible spectrum
Conjugated aromatic compounds, such as aromatic amino acids absorb ——— radiation.
a) Infrared
b) Microwave
c) Radio
d) Ultra violet
d) Ultra violet
The visible range is from ——— nm.
a) 190 - 380
b) 200 - 780
c) 400 - 780
d) 800 - 1000
c) 400 - 780
8) Compounds that absorb UV radiation are normally measured in cuvettes made of ———-
Compounds that absorb UV radiation are normally measured in cuvettes made of quartz
In case of determining the maximum wavelength of a compound in presence of other compounds that they overlap with it, the absorbance of the compound to be measured should be determined at the wavelength that gives it its highest absorbance.
a) True
b) False
a) True
If you did not find any letters on the cuvette, that means it is made of ——
a) Glass
b) Quartz
c) Plastic
c) Plastic
We see ———- colour when the substance doesn’t absorb any white light.
a) Black
b) Blue
c) Red
d) White
We see white colour when the substance doesn’t absorb any white light.
The ___________ is either a prism or a diffraction grating that separates the white light into all colors of the visible spectrum
a) Monochromator
b) Polychromator
c) Spectrophotometer
d) Wavelength
The monochromator is either a prism or a diffraction grating that separates the white light into all colors of the visible spectrum
A spectrophotometer is designed to detect ———————– of light at different ——————- when the light passes through a solution of a given concentration.
a) Absorbance, wavelengths
b) Photodetector, wavelength
c) Wavelength, absorbance
d) Wavelength, temperature
A spectrophotometer is designed to detect Absorbance of light at different wavelengths when the light passes through a solution of a given concentration.
A ——————- is used for UV spectrophotometer.
a) Hydrogen gas lamp
b) Laser beam
c) Cadmium lamp
d) Tungsten lamp
a) hydrogen gas lamp
(also mercury & deuterium lamps)
—– is the amount of light that has been absorbed by the sample; and the relationship between sample concentration and absorbance is —— up to a certain concentration.
Whereas, —– is the fraction of incident light that passes completely through the sample; and the relationship between the sample concentration and transmittance is ——-.
a) Absorbance
b) Transmittance
c) Linear (directly proportional)
d) Exponential (inversely proportional)
Absorbance is the amount of light that has been absorbed by the sample; and the relationship between sample concentration and absorbance is Linear (directly proportional) up to a certain concentration.
Whereas, Transmittance is the fraction of incident light that passes completely through the sample; and the relationship between the sample concentration and transmittance is Exponential (inversely proportional).
The ultraviolet range is ——— nm.
a) Below 400
b) 200 - 780
c) 400 - 780
d) 800 – 1000
e) Above 1000
a) Below 400
A ——————- is used for Vis spectrophotometer.
a) Deuterium lamp
b) Hydrogen gas lamp
c) Laser beam
d) Mercury lamp
e) Tungsten lamp
e) Tungsten lamp
A monochromatic filter only allows a narrow range of —– (essentially a single colour) to pass.
a) Absorbance
b) Concentration
c) Wavelength
c) Wavelength
The visible light is used to detect ——— substances, whereas the ultra-violet is used for ———-substances.
a) Coloured
b) Colourless
The visible light is used to detect coloured substances, whereas the ultra-violet is used for colourless substances.
A —————— is used to block out unwanted light of different colours
a) Filter
b) Monochromator
c) Spectrophotometer
d) Prism
a) filter
Arrange the following amino acids from the lowest to the highest in terms of their maximum wavelength at the UV range:
Tyrosine – Tryptophan - Phenylalanine.
a) Trp – Tyr - Phe
b) Trp – Phe – Tyr
c) Tyr – Phe - Trp
d) Phe – Trp - Tyr
e) Phe – Tyr - Trp
e) Phe – Tyr - Trp
(FYW)
name 5 possible uses for the UV spectrometer:
- Protein
- Amino Acids (aromatic)
- Pantothenic Acid (B5)
- Glucose Determination
- Enzyme Activity (Hexokinase)
Which of the following compounds are more likely to be detected at the ultraviolet range?
I. Alanine
II. Glycine
III. Serine
IV. Tyrosine
V. Tryptophan
a) I & III
b) I, II & III
c) I, II & V
d) II, II & IV
e) IV & V
e) IV & V
We see ——— colour when the substance does absorb all colours except red colour.
a) Black
b) Blue
c) Red
d) White
We see red colour when the substance does absorb all colours except red colour.
6) A ————– lamp is used for UV spectrophotometer.
A Hydrogen gas, mercury or duterium lamp can be used for UV spectrophotometry
Cuvettes were made of what 6 possible materials:
- Glass
- Quartz
- Plastic
- Sapphire
- Infra red quartz
- Fused quartz
5) A ————– lamp is used for Vis spectrophotometer.
A Tungsten lamp is used for Vis spectrophotometer.
