Question 1 - EM radiation and visible light Flashcards
(19 cards)
What is the wavelength of red light?
620-780nm
What is the wavelength of orange light?
585-620nm
What is the wavelength of yellow light?
570-585nm
What is the wavelength of green light?
490-570nm
What is the wavelength of blue light?
440-490nm
What is the wavelength of indigo light?
420-440nm
What is the wavelength of violet light?
400-420nm
If a UV visible spectrum absorbs light at x nm what colour is the compound?
The complimentary colour of the colour being absorbed.
What is the complimentary colour of red?
Green
What is the complimentary colour of orange?
Blue
What is the complimentary colour of yellow?
Purple (violet/indigo)
What equation is used to calculate the molar extinction coefficient?
A = e c l
A = absorbance
e = molar extinction coefficient
c = concentration
l = path length
What is the SI unit for the molar extinction coefficient?
m2mol-1
What is the equation to calculate the frequency of a photon?
c = f λ
c = speed of light
f = frequency
λ = wavelength
What is the equation to calculate the energy of a photon?
E = h f
E = energy
h = planck’s constant
f = frequency
What is the nature of the electronic transition that gives rise to this absorption of a photon?
The energy of the d orbital splits by the presence of the compound’s ligands. The gap between these is the energy of the photon. Therefore the complex can absorb a photon with the given wavelength, promoting an electron from the lower to the higher d orbital.
How would a calibration graph of concentration and measured absorbance be plotted?
x = concentration
y = measured absorbance
How do you find the molar extinction coefficient from a calibration graph?
The gradient
When using A = ecl what unit should the pathlength be in?
cm if the conc is in mol-1dm3, m if mol-1m3
