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A Beer's Law Plot of sample A gives a slope equal to 1.2 M-1cm-1. Calculate molar concentration of this sample at a wavelength of 420 nm and an absorbance reading of 0.23 in a 1 cm cuvette.

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boffeemadrid

Answer:

[tex]0.192\ \text{M}[/tex]

Explanation:

A = Absorbance of solution

E = Molar absorptivity

l = Length of cuvette = 1 cm

c = Concentration of solution

Beer's law is given by

[tex]A=Elc[/tex]

The equation of a straight line is given by

[tex]y=mx+c[/tex]

Comparing the above equations we get

Value on [tex]y[/tex] axis = A = Absorbance of solution = 0.23

[tex]m[/tex] = Slope of line = El = Molar absorptivity multiplied with length = [tex]1.2\times 1\ \text{M}^{-1}[/tex]

[tex]x[/tex] = Value of x axis = c = Concentration of solution

So we get

[tex]c=\dfrac{A}{El}\\\Rightarrow c=\dfrac{0.23}{1.2\times 1}\\\Rightarrow c=0.192\ \text{M}[/tex]

The molar concentration of the sample is [tex]0.192\ \text{M}[/tex]

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