Question

Data Table 1.4. Preparation of Bromophenol Blue Dilution Series 11 Volume of 0.040 mM Sample Tube Volume of Total Volume (ml) Concentration Bromophenol Blue Stock (ml) Absorbance Water (ml) (mM) 1 (blank) 0.0 8.0 0.000 B.O 0.00 mM 2 .a3g 1.0 7.0 8.0 3 451 .48 2.0 6.0 8.0 4 3.0 5.0 B.O 5 4.0 4.0 8.0 6 5.0 3.0 8.0 1.023 7 6.0 2.0 8.0 8 7,0 1.0 8.0 I. 25 1.342 8.0 0.0 8.0 341 Unknown 8.0 ml of Unknown 0.0 8.0

What is the concentration?

Answer 1

Concentration mM Absorbance 1 2 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04 0.238 0.451 0.648 0.698 0.868 1.023 1.205 1.342 V = 32.110.077 R = 0.9885, Absorbance 0 0.005 0.01 0.035 0.04 0.045 0.015 0.02 0.025 0.03 Bromophenol Blue in mM

y = absorbance

x = concentration in mM

For unknow y = 0.347.

So, 0.347 = 32.11x +0.077

0.347 - 0.077 = 32.11x

0.27 = 32.11x

x = 0.27/32.11

= 0.0084 mM.

So the concentration of Unknown is 0.0084mM.

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