Question

The absorbance of a chemical solution is 0.5 at 400 nm. The concentration of the solution is 50 mM. The pathlength of the cuvette is 1 cm. What is the molar absorptivity of the chemical at this wavelength?

Answer #1

The formula for absorbance is :- A = ɛ x l x c

In this, A is absorbance, ɛ is molar abaorptiviy, l is length of the cuvette and c is the concentration of the solution.

Now we can move the equation for ɛ and it becomes :-

ɛ = A/lc (Here we took lc to the other side)

Now we have the values of A, l and c given.

A is 0.5

c is 50mM = 0.05 M (We converted it into M by dividing 50 with 1000)

l is 1 cm

So putting the values in the equation

ɛ = 0.5/(1 X 0.05)

ɛ = 10 L Mol-1 cm-1

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