Question

If a mixture was prepared by diluting 7.0 mL of the Blue#1 solution with water to a final volume of 10.0 mL and mixing this with 2.0 mL of diluted bleach how many seconds would it require for the mixture to have an absorbance of 0.120? Use your measured values of eb and of the average rate constant, k to answer this question. Show all work.

eb= 0.1138

k= -0.035

first order reaction

Concentration of Blue Solution= 15 M

Answer 1

Given- eb = 0.1138

K = 0.035

Cocentration of blue solution= 15M

Absorbance= 0.120

Formula-

Absorbance = A = $\varepsilon$ x C x b

Dilution law - M1V1= M2V2

Solution-

A =  $\varepsilon$ x C x b

0.120 = 0.1138 L Mol-1 x C Mol L-1

C = 1.0545 M

First order = [At] = [A0] x e -Kt

1.0545 = 15 x e -0.035 x t

ln 1.0545 = ln 15 - 0.035t

0.0531 = 2.7081 -  0.035t

t = 75.86 seconds.

time = 76 seconds.

Answer- It would take 76 seconds for mixture to attain absorbanc 0.120