Respuesta :
Answer:
The answer is "[tex]4.875 \ \frac{mol}{l}\\[/tex]".
Explanation:
The molar absorptivity value is= 12.3 [tex]\frac {L}{mol \times cm}[/tex]
path length of cell = 1 [tex]\ cm[/tex]
Absorbance = 1.2
Using the beer's lambert law:
[tex]A = \varepsilon \ cl\ \ \ \ \ \ \ _{where} \\\\c= \frac{A}{ \varepsilon l } \\\\[/tex]
[tex]= \frac{1.2}{12.3 \times 1}\\\\= 0.0975 \ \frac{mol}{L}\\[/tex]
Claculating the concentration of the solution after dilution: [tex](m_2)= 0.0975 \ \ \frac{mol}{L}[/tex]
find out the dilution value before concentration :
The volume taken by the dilution: [tex](V_1) = 0.2\ ml[/tex]
The final volume after dilution:
[tex](V_2) = 9.8+0.2\\[/tex]
[tex]= 10 \ ml[/tex]
Formula:
[tex]\bold{M_1 \times V_1 = M_2 \times V_2} \\\\ M_1= \frac{M_2 \times V_2 }{V_1}\\\\[/tex]
[tex]= \frac{ 0.0975 \times 10 }{0.2}\\\\= \frac{ 0.975 }{0.2}\\\\ = 4.875 \ \frac{mol}{l}\\[/tex]
