Principles of Instrumental Analysis
7th Edition
ISBN: 9781305577213
Author: Douglas A. Skoog, F. James Holler, Stanley R. Crouch
Publisher: Cengage Learning
expand_more
expand_more
format_list_bulleted
Concept explainers
Question
Chapter 15, Problem 15.10QAP
Interpretation Introduction
Interpretation:
The percentage of quinine in the tablet should be determined.
Concept introduction:
The expression of percentage of quinine in the sample of
Expert Solution & Answer
Trending nowThis is a popular solution!
Students have asked these similar questions
tion 13 of 24 >
The standard curve was made by spectrophotographic analysis of equilibrated iron(III) thiocyanate solutions of known
concentration. You are asked to analyze a Fe(SCN)²+ solution with an unknown concentration and an absorbance value of 0.179.
The slope-intercept form of the equation of the line is y = 4536.6x + 0.0392. The unknown was analyzed on the same
%3D
instrument as the standard curve solutions at the same temperature.
What is the Fe3+ concentration of the unknown solution?
Iron(III) thiocynate standard curve
1.0 -
Fe*] =
mol/L
0.5-
0.0001
0.0002
Fe+ concentration (M)
Absorbance
Complexometric titrations are generally conducted to determine divalent cations. The most
important applications are the titration of calcium and magnesium with EDTA.
(a)
A supplement tablet containing about 300.00 mg of calcium ion was dissolved, filtered,
and diluted to 100.00 ml volume. Several 2.00 ml samples of the total solution were
titrated with 0.0100 M EDTA solution. The mean corrected titration volume was 13.65
mL. Calculate the calcium content of the supplement tablet in mg units.
(b)
A sample of Epsom Salt of mass 0.7567 g was dissolved uniformly in distilled water in
a 250.00 mL volumetric flask. Portions of the magnesium ion solution of volume 10.00
mL were titrated using a 0.01000 M solution of EDTA. The mean corrected titration
volume was 12.25 ml. Calculate the percentage by mass (% w / w) of the magnesium
in the Epsom Salt sample.
(c)
A 100.00 mL sample of tap water was titrated with 0.0100 M EDTA solution. The mean
corrected titration volume was 14.80 mL. Determine…
Solutions of cobalt (II) ions have a magenta color with a molar absorptivity constant (e) value at 511 nm of 5.87 M-1cm-1. A 0.500 mL sample is transferred from a 50.0 mL stock solution of Co(NO3)2 and diluted with water to a final volume of 7.50 mL. The dilution had an absorbance value at 511 nm in a standard cuvette (1.00 cm light path) of 0.382. Calculate the mass of Co(NO3)2 contained in the original 50.0 mL stock solution.
Chapter 15 Solutions
Principles of Instrumental Analysis
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, chemistry and related others by exploring similar questions and additional content below.Similar questions
- The acid-base indicator HIn undergoes the following reaction in dilute aqueous solution: HIncolor1H++Incolor2 The following absorbance data were obtained for a 5.00 I0-4 M solution of HIn in 0.1 M NaOH and 0.1 M HC1. Measurements were made at wavelengths of 485 nm and 625 nm with 1.00-cm cells. 0.1 M NaOH A485 = 0.075 A625 = 0.904 0.1 M HC1 A485 = 0.487 A625 = 0.181 In the NaOH solution, essentially all of the indicator is present as In-; in the acidic solution, it is essentially all in the form of HIn. (a) Calculate molar absorptivities for In- and HIn at 485 and 625 nm. (b) Calculate the acid dissociation constant for the indicator ¡fa pH 5.00 buffer containing a small amount of 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 organic acid HX required exactly 24.20 mL of a standard solution of a strong base to reach a phenolphthalein end point. When exactly 12.10 mL of the base was added to a second 25.00-mL aliquot of the acid, which contained a small amount of the Indicator under consideration, the absorbance was found to be 0.333 at 485 nm and 0.655 at 625 nm (1.00-cmcells). Calculate the pH of the solution and Ka for the weak acid. (e) What would be the absorbance of a solution at 485 and 625 nm (1.50-cm cells) that was 2.00 10-4 M in the indicator and was buffered to a pH of 6.000?arrow_forwardUse the following atomic masses (in g/mol): Mg = 24.31; O = 16; Ca = 40.08; C = 12.01; Na = 23; H = 1; N = 14.01; S = 32.06; Cl = 35.45; 8.) A sample of Chlorpheniramine Maleate weighing 0.502g was assayed by non-aqueous titrimetry using 22.2mL of HClO4 having a N of 0.1125. Calculate the %P. Each mL of 0.1N HClO4 is equivalent to 19.54mg of Chlorpheniramine Maleate.arrow_forwardThe molar absorptivities of an indicator HIn (Ka = 4.6 × 10-5) and its conjugate base In− at 630 nm were determined as εHIn = 821 and εIn- = 375, respectively. Calculate the absorbance A (b = 1.00 cm) for the buffered indicator solution with a total HIn concentration of 6.32 × 10-4 M at pH = 4.00arrow_forward
- 0,0585g Na2C204 10 ml 'to adjust KMN04 solution prepared as 0,1M distilled water, 2 M H2SO4 was added, heated and 8.4 ml titrant has been spent. Calculate the true concentration of potassium permanganate accordingly.arrow_forwardAn unknown sample containing mixed alkali (NaOH, NaHCO3, or NazCO3) was analyzed using the double flask method. A 250 mg sample was dissolved in 250 mL CO2 free water. A 20.0 mL aliquot of this sample required 11.3 mL of 0.009125 M HCI solution to reach the phenolphthalein end point. Another 29.0 mL aliquot of the sample was titrated to the bromocresol green endpoint using 31.1 mL of the standard acid. How many millimoles of the components are there in the original solid sample? O 0.28 mmol Na2CO3 O 1.29 mmol NAOH, 0.97 mmol Na2CO3 O 01 mmol NaOH, 0.078 mmol NazCO3 O 1.29 mmol NażCO3, 0.97 mmol NaHCO3 O Cannot be determinedarrow_forwardA 10.00mL sample of alcoholic ethyl acetate was diluted to 100.00 mL. 20.00 mL was aliquoted and mixed with 40.00 mL of 0.04672 M KOH. The resulting mixture was heated for 2 hours. CH3COOC2H5 + OH- → CH3COO- + C2H5OH After cooling, the excess OH was back titrated with 3.41 mL of 0.05042 M H2SO4. Answer the following: Calculate the number of moles of OH- that reacted with ethyl acetate. Calculate the number of moles of ethyl acetate in the 20.00 mL solution. What is the mass of ethyl acetate (FW=88.11 g/mol) in the original 10.00 mL sample?arrow_forward
- [Standardization] A 0.3045 g of CaCO3 primary standard was dissolved using concentrated HCl, evaporated to incipient dryness, and quantitatively transferred to a 250 mL volumetric flask and diluted to mark. A 10 mL of aliquot was then transferred to an Erlenmeyer flask, together with 5mL buffer and 5 drops of EBT indicator, and was used to standardize the EDTA titrant. The solution turned blue after the addition of 24.10 mL of EDTA. A blank correction was made and was determined to be 0.4 mL. [Analysis] A 30 mL unknown water sample was treated with 37.6 mL of EDTA. A blank correction was made and was determined to be 0.4 mL. What is the concentration of CaCO3 of the unknown water sample in ppm? (MW CaCO3 = 100.0869 g/mol)?arrow_forward[Standardization] A 0.3045 g of CaCO3 primary standard was dissolved using concentrated HCl, evaporated to incipient dryness, and quantitatively transferred to a 250 mL volumetric flask and diluted to mark. A 10 mL of aliquot was then transferred to an Erlenmeyer flask, together with 5mL buffer and 5 drops of EBT indicator, and was used to standardize the EDTA titrant. The solution turned blue after the addition of 24.10 mL of EDTA. A blank correction was made and was determined to be 0.4 mL. [Analysis] A 30 mL unknown water sample was treated with 37.6 mL of EDTA. A blank correction was made and was determined to be 0.4 mL. What is the concentration of CaCO3 of the unknown water sample in ppm? (MW CaCO3 = 100.0869 g/mol)? 633.43 ppm CaCO3 626.71 ppm CaCO3 637.27 ppm CaCO3 644.11 ppm CaCO3arrow_forwardIn a Complexometric Titration Experiment, the preparation of the EDTA solution is as follows: In a 250 mL beaker, weigh 0.10 g MgCl2*6H2O and 1.0 g NaOH. Add approximately 200 mL distilled water and stir to dissolve. Add about 2.0 g of EDTA and transfer the solution quantitatively to a 1-L volumetric flask. Dilute to the mark with distilled water. What is the purpose of adding MgCl2*6H2O? Please show COMPLETE solution.arrow_forward
- [Standardization] A 0.3045 g of CaCO3 primary standard was dissolved using concentrated HCl, evaporated to incipient dryness and quantitatively transferred to a 250 mL volumetric flask, and diluted to mark. A 10 mL of aliquot was then transferred to an Erlenmeyer flask, together with 5mL buffer and 5 drops of EBT indicator, and was used to standardize the EDTA titrant. The solution turned blue after the addition of 24.10 mL of EDTA. A blank correction was performed and was determined to be 0.4 mL. What is the concentration of EDTA obtained (MW CaCO3 = 100.0869 g/mol)? 5.050 x 10-3 M 0.1284 M 0.1262 M 5.135 x 10-3 Marrow_forwardAn unknown sample containing mixed alkali (naoh, nahco3, or na2co3) was analyzed using the double flask method. a 250 mg sample was dissolved in 250 ml co2 free water. a 20.0 ml aliquot of this sample required 11.3 ml of 0.009125 m hcl solution to reach the phenolphthalein end point. another 29.0 ml aliquot of the sample was titrated to the bromocresol green endpoint using 31.1 ml of the standard acid. how many millimoles of the components are there in the original solid samplearrow_forwardA 5.323 g of dried eggshell is transferred to a 250-mL beaker and dissolved in 25 mL of 6 M HCl. The mixture was filtered and transferred into a 250 mL volumetric flask and diluted to the mark. A 20.00-mL aliquot is placed in a 125-mL Erlenmeyer flask and buffered to a pH of 10. The mixture was titrated with 0.04992 M EDTA and 43.25 mL was consumed to reach the end point. Determine the amount of calcium in the eggshell as %w/w calcium carbonate.arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
Principles of Instrumental AnalysisChemistryISBN:9781305577213Author:Douglas A. Skoog, F. James Holler, Stanley R. CrouchPublisher:Cengage Learning
Principles of Instrumental Analysis
Chemistry
ISBN:9781305577213
Author:Douglas A. Skoog, F. James Holler, Stanley R. Crouch
Publisher:Cengage Learning