I. (a) Solution I is 0.088 M in compound Z and has an absorbance of 0.253 in a 1

Question

I.               (a) Solution I is 0.088 M in compound Z and has an absorbance of 0.253 in a 1 cm cell at 520 nm. The solvent alone exhibits an absorption of 0.079 in the same cell. What is the concentration of Z in solution II if the absorbance of solution II in the same cell and at the same wavelength is 0.377?  5 pts.

[Z] = ______ M

(b) Suppose a mixture of two solutions (of the same solute, Z) is prepared by adding 245.-mL of 0.0335 M solution to 97.0-mL of 0.932 M solution. What is the concentration of Z in the combined solution? 5 pts.

[Z] = ______ M

Explanation / Answer

a) A = el C el are constants ,

A2/A1 = C2/C1

0.377/0.253 = C2/0.088

C2 = 0.13 M

b) total moles = (0.245 x0.0335) + ( 0.097 x 0.932) = 0.099

vol total = 245+97 = 342 ml = 0.342 L

[Z] = 0.099/0.342 = 0.2895 M

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