In a laboratory experiment, you are asked to determine the molar concentration of a solution of an unknown compound, X. The solution diluted in with water (200 µL of X + 800 µL of H2O) has an absorbance at 425 nm of 0.8 and a molar extinction coefficient of 1.5 x103 M-1cm-1 at 425 nm. What is the molar concentration of the original solution of X?

Complete Question

In a laboratory experiment, you are asked to determine the molar concentration of a solution of an unknown compound, X. The solution diluted in with water (200 µL of X + 800 µL of H2O) has an absorbance at 425 nm of 0.8 and a molar extinction coefficient of 1.5 x103 M-1cm-1 at 425 nm. What is the molar concentration of the original solution of X? (1 cm cuvette)

The original concentration is

Explanation:

From the question we are told that

The original volume of solution X is

The volume of solution X after dilution is

The absorbance is

The molar extinction coefficient is

Generally from Beer's law

Here

L is the path length with a value of 1 cm

C_2 is the concentration of the solution at the given absorbance

=>

=>

=>

Generally we have that

=>

number of molecules / avogadro's number * molecule molecular = mass

explanation:

we define a gram-molecular weight as the mass of one mole of any element or compound. a mole contains avogadro's number of units (molecules) –  

6.022

x

10

23

. so, dividing the number of molecules by avogadro's number gives us the number of moles. multiplying that by the molecular weight gives us the mass. from the periodic table we find the gram-molecular weight of u to be238 and of f to be19. so,  

u

f

6

will have a gram-molecular weight of 352g.

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