-How do you find the concentrations of HCl, H2A, MB+ in the solution (total volu

Question

-How do you find the concentrations of HCl, H2A, MB+ in the solution (total volume=2000uL)? I cannot figure out how to do it at all.
-Stock concentrations are 0.104M HCl, 0.1001M H2A, 0.0002M MB+, H20 is 55.5M i believe but am not 100% sure.
-Please show work/how to get answer!

Also, less important, but if you can answer how to convert absorbance to concentration using an extinction coefficient of 56,814 M^-1 cm^-1. I believe you just divide the absorbance by the coefficient, but just wanted to make sure. Thanks!!!!

Table I: Kinetics Reaction Mixtures Trial Volume of HCl Volume of ascorbic Volume of methylene Volume of H20 blue (MB+) acid (H2A) Al 600 L 500 L 100 L 800 L

Explanation / Answer

1) We shall use the dilution equation:

M1*V1 = M2*V2

M1 = molar concentration of the more concentrated (stock) solution

M2 = molar concentration of the less concentrated (dilute) solution

V1 = volume of the more concentrated (stock) solution

V2 = volume of the less concentrated (dilute) solution

The total volume of the less concentrated (dilute) solution for all the three cases is 2000 µL. Plug in values for each of the three to find the final concentrations.

HCl:

(600 µL)*(0.104 M) = (2000 µL)*[HCl]f

===> [HCl]f = (600*0.104 M)/(2000) = 0.0312 M (ans)

H2A:

(500 µL)*(0.1001 M) = (2000 µL)*[H2A]f

===> [H2A]f = (500*0.1001 M)/(2000) = 0.025025 M (ans)

MB+:

(100 µL)*(0.0002 M) = (2000 µL)*[MB+]f

===> [MB+]f = (100*0.0002 M)/(2000) = 0.00001 M (ans).

2. The relation between absorbance (A) and the concentration (c) is

A = *c*l where = absorptivity co-efficient and l = path length of the solution. Only when l = 1, you can use the relation

c = A/ (ans).

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