3. An indicator is a dye whose spectrum changes with pH. Consider the following data for theabsorption spectrum of an indicator (pK = 4) in its ionized and nonionized form.InH+ → In + H*Molar absorptivity, ɛ(M1.cm1)InH+(nm)In40010,00042015,0002,0004408,0008,00046012,0004803,000The absorbance of the indicator solution is increased in a 1-cm cell and found to be400420440460480(nm)A0.250 0.425 0.400 0.300 0.075a. Calculate the pH of the solution. [4.0]b. Calculate the absorbance of the solution at 440 nm and pH 6.37 for the same total indicatorconcentration. [0.400]c. If you want to measure the quantum yield of fluorescence of In and H* independently,what wavelength would you choose for exciting In H+? For exciting In? Why?

Answered: Image /qna-images/answer/89620f12-6d74-426f-bd79-e360d0e9d30c.jpg

3. An indicator is a dye whose spectrum changes with pH. Consider the following data for the absorption spectrum of an indicator (pK = 4) in its ionized and nonionized form. InH* + In + H* Molar absorptivity, ɛ (M1.cm-1) InH (nm) In 400 10,000 15,000 8,000 420 2,000 8,000 12,000 3,000 440 460 480

3. An indicator is a dye whose spectrum changes with pH. Consider the following data for the absorption spectrum of an indicator (pK = 4) in its ionized and nonionized form. InH* + In + H* Molar absorptivity, ɛ (M1.cm-1) InH (nm) In 400 10,000 15,000 8,000 420 2,000 8,000 12,000 3,000 440 460 480

Chemistry

10th Edition

ISBN:9781305957404

Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Publisher:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Chapter1: Chemical Foundations

Section: Chapter Questions

Problem 1RQ: Define and explain the differences between the following terms. a. law and theory b. theory and...

See similar textbooks

Similar questions

In the laboratory, a general chemistry student measured the pH of a 0.589 M aqueous solution of phenol (a weak acid), C6H5OH to be 4.997. Use the information she obtained to determine the K₂ for this acld. Ka(experiment) = Submit Answer $ 4 R LL F F4 % 5 A T Retry Entire Group 9 more group attempts remaining G Cengage Learning Cengage Technical Support F5 A 6 MacBook Air S Y H & 7 ◄◄ F7 U J * 00 8 ► 11 F8 L ( 9 K F9 O 1 0 L F10 P 4) Previous Next F11 + = Save and F12 8
6) Bu analyst in a solution uning two dierent indicators. lis results were an /lowes : meanired the con cen tration n aid Mean [HCI]+ Stand Dev. 002467テ 0.0045 Indi cator A: 18 12 Indicator B: 0-02407 チ0.0032 Is the difference between te tueo indican Ys figniticand at he 95%. confiden ce loue/?
3) What is the pH of a 0.02 M solution of sodium propionate? (12 pts) Reaction of sodium propionate in water: Pr (aq) + H₂O (1) ⇒ HPr (aq) + OH-(aq) Ka= 10-4.⁹ *Hint* This is a Kb problem therefore you must convert ka to Kb. You can assume that the sodium propionate dissociates completely from the propionate and is not involved in any other important reactions. a) Is this the conjugate base or an acid that you are adding to solution? b) Write down the Mass-Balance Relations, the Proton Balance Relation and the c) Equilibrium Relation. Calculate the pH using both an analytic method, and by drawing the predominance diagram. *Hint* [OH-]=[HPr].
The value of Ksp for Mg3(AsO4)2 is 2.1 x 10-20. TheAsO43 - ion is derived from the weak acid H3AsO4 (pKa1 =2.22; pKa2 = 6.98; pKa3 = 11.50). (a) Calculate the molarsolubility of Mg3(AsO4)2 in water. (b) Calculate the pH of asaturated solution of Mg3(AsO4)2 in water.
0 The acid-base indicator HIn undergoes the following reaction in dilute aqueous solution:HIn color1 m H1 1 In2color2The following absorbance data were obtained for a 5.00 3 1024M solution of HIn in 0.1 M NaOH and0.1 M HCl. Measurements were made at wavelengths of 485 nm and 625 nm with 1.00-cm cells.0.1 M NaOH A485 5 0.075 A625 5 0.9040.1 M HCl A485 5 0.487 A625 5 0.181In the NaOH solution, essentially all of the indicator is present as In2; in the acidic solution, it is essentiallyall in the form of HIn.(a) Calculate molar absorptivities for In2 and HIn at 485 and 625 nm.(b) Calculate the acid dissociation constant for the indicator if a pH 5.00 buffer containing a small amountof the indicator exhibits an absorbance of 0.567 at 485 nm and 0.395 at 625 nm (1.00-cm cells).(c) What is the pH of a solution containing a small amount of the indicator that exhibits an absorbance of0.492 at 485 nm and 0.245 at 635 nm (1.00-cm cells)?(d) A 25.00-mL aliquot of a solution of purified weak…
ALL INFORMATION NEEDED IS PROVIDED, I NEED FIRST QUESTIONS ANSWERED FIRST BEFORE OTHERS CAN BE ANSWEREDRate = -(Delta[RCl])/Delta t andln[RCl]t=-k*t+ln[RCl]0 < [R-Cl]-time equation Test tube A = 0.30 of 0.10M NaOH(aq), 6.70ml DI H2O & 1 drop of bromophenol bue Test Tube B = 3.00M of 0.10M R-CL in acetone. Mix together in 3 water baths Bath A Trial 1= 20C, 53.6s Trial 2= 20C, 49s for color to changeBath B Trial 1= 32C, 18s Trail 2= 32C, 20s Bath C Trial 1= 10C, 204s Trial B= 10C, 200s average out both trials for each bathcolor change happens after 10% of R-Cl has reacted so In terms of R-Cl this means that 10% of the R-Cl has reacted and ____ of the R-Cl is left Q1. at the time of the color change [R-Cl]t=____[R-Cl]o (Fill in the blank) Q4. Substitute the value of [R-Cl]t into appropriate equation listed above and solve for k in terms of [R-Cl] and t. Q5. Use average time for each temp and determine the value of k (with units) at each temperature Q6. Rearrange the Arrhenius…
9-10. (a) Find the pH of a solution prepared by dissolving 1.00 g of glycine amide hydrochloride plus 1.00 g of glycine amide in 0.100 L. + Cl- H3N H2N. NH2 NH2 Glycine amide hydrochloride (BH†) FM 110.54, pK, = 8.20 Glycine amide (B) FM 74.08 (b) How many grams of glycine amide should be added to 1.00 g of glycine amide hydrochloride to give 100 mL of solu- tion with pH 8.00? (c) What would be the pH if the solution in (a) is mixed with 5.00 mL of 0.100 M HC1? (d) What would be the pH if the solution in (c) is mixed with 10.00 mL of 0.100 M NaOH?
The following is an alpha plot for a monoprotic weak acid, HA. 1.0 CL 0.5 2 4 6 pH 8 10 12 14 HA A ►
Given the chemical equation for the anthocyanin extract of red cabbage as an indicator. HIn + H20 S H;0* + In¯ Using the results from the experiment, identify which of the reactant/product are responsible for the red and green color of the indicator. Notes: solution turns red after adding acid; solution turns blue/green after adding base RED: BLUE/GREEN: Why is the color violet/blue at pH near 7? Answer in 1 sentence. Hint: What is the relationship of the species responsible for the observed colors?
Full acid, HOOC = CH-COOH is a biphatic acid and we will label it as H2M. Acid constant data for the two protonation phases of the acid: K H.M+H2O = H, 0++HM- HM +H2O = H, 0++M2– a1 = 1.3x10-2 K.2 = 5.9 x 10-7 Measure 0.1 ml of 0.100 M of malic acid with 0.100M NaOH and measure the H variability as a function of the added base volume. A. Calculate the PH value at the beginning of the titration. B. Calculate the pH value at the first equivalent point. C. Calculate the pH value at the second equivalent point. D. Draw the titration curve in the graph. Indicate in the graph titles and units for the axes.
pH Measurement Experiment 1. Objectives: Explore different methods of measuring ph II. Materials: water window cleaner pH meter apple juice 0.1 M NaCl pH paper milk 0.1 M FeCl₂ litmus paper red/blue III. Results and Observations Red litmus paper water apple juice milk window cleaner 0.1 M NaCl 0.1 M FeCl3 IV. Conclusion Blue litmus paper Acidic/basic/neutral PH
4. The molar absorptivities of the indicator weak acid HIn (K₁ = 1.42 x 105) and its conjugate base In at 570 were determined as ε(HIn) = 7120 and ɛ(In) = 961. The optical length b = 1.00 cm. (a) What is the absorbance of an unbuffered indicator solution having total indicator concentration 8.0 × 10%. (b) What is the absorbance of a buffered indicator solution having total indicator concentration 8.0 x 105 and pH = 6.5.