A cuvette of length l is filled with a solution
of aspirin with concentration c. You are recording
the transmission of light of a certain wavelength and record a
transmission of T=90%. A= -log(%T / 100%), A=*b*c.
Show your work to receive credit.
a) What is the absorbance of the solution?
b) The concentration of aspirin is increased by a factor of 2. What is the absorbance of the cell? What is the transmission of the cell?
c) The concentration of aspirin is decreased by a factor of 2. What is the absorbance of the cell? What is the transmission of the cell?
A = εbc
ε = molar absorptivity = liters/mole cm
b = cell path length = cm
c = concentration = moles/liter
A= -log(%T / 100%) or A = log10(100/T) = log10(100) - log10 (T) = 2 - log10 (T)
a) Given T = 90% = 90/100 = 0.9, A = 2 - log10 (T) = 2 - log10 (0.9) = 1.95
absorbance of the solution = 1.95
b) If the solution concentration increases by a factor of 2 then the absorbance will also increase by a factor of 2.
absorbance of the cell = 1.95*2 = 3.9
transmission of the cell T = 10-A = 10-3.9= 0.01259%
c) If the solution concentration decreases by a factor of 2 then the absorbance will also decrease by a factor of 2.
absorbance of the cell = 1.95/2 = 0.975
transmission of the cell T = 10-A = 10-0.975= 10.59%
A cuvette of length l is filled with a solution of aspirin with concentration c. You...
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