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11 Nov 2019
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A two-colored acid-base indicator has an acid form, which absorbs visible radiation at 410 nm with a molar absorptivity of 347 liter-mole-1 cm·1·The base form of the indicator has an absorption band with a maximum of 640 nm and a molar absorptivity of 100 liter-mole 1 cm. In addition, the acid form does not absorb significantly at 640 nm, and the base form exhibits no measurable absorbance at 410 nm. A small quantity of the indicator was added to an aqueous solution, and the absorbance values were observed to be 0.118 at 410 nm and 0.267 at 640 nm for a 1-cm spectrophotometric cell. Assuming that the indicator has a pKa value of 3.90, calculate the pH of the aqueous solution 8. Estimate pK, of an acid from the data below. Concentration of acid in each buffer solution is 0.001M. Only A absorbs 9. pH Absorbance 6 0.10 0.75 1.00 1.15 1.25 1.25 10 10. The following data were obtained in the absorption measurement of solutions containing the bipyridine complex of iron. Absorbance 0.077 0.126 0.230 0.280 Concentration 0.40ppm 0.80ppm Application of linear regression to the data gave a slope of 0.254 and an intercept of 0.025. What is the concentration of iron in a solution when the measured absorbance is 0.200, assuming the same measurement conditions?
Could you write clearly ?
A two-colored acid-base indicator has an acid form, which absorbs visible radiation at 410 nm with a molar absorptivity of 347 liter-mole-1 cm·1·The base form of the indicator has an absorption band with a maximum of 640 nm and a molar absorptivity of 100 liter-mole 1 cm. In addition, the acid form does not absorb significantly at 640 nm, and the base form exhibits no measurable absorbance at 410 nm. A small quantity of the indicator was added to an aqueous solution, and the absorbance values were observed to be 0.118 at 410 nm and 0.267 at 640 nm for a 1-cm spectrophotometric cell. Assuming that the indicator has a pKa value of 3.90, calculate the pH of the aqueous solution 8. Estimate pK, of an acid from the data below. Concentration of acid in each buffer solution is 0.001M. Only A absorbs 9. pH Absorbance 6 0.10 0.75 1.00 1.15 1.25 1.25 10 10. The following data were obtained in the absorption measurement of solutions containing the bipyridine complex of iron. Absorbance 0.077 0.126 0.230 0.280 Concentration 0.40ppm 0.80ppm Application of linear regression to the data gave a slope of 0.254 and an intercept of 0.025. What is the concentration of iron in a solution when the measured absorbance is 0.200, assuming the same measurement conditions?
Jarrod RobelLv2
29 Jun 2019