A sample was analysed for its Calcium concentration. A number of standard solutions were prepared (ppm) and their absorbance values were determined. The results were plotted in Excel (concentration on x-axis and absorbance on y-axis) and the following equation for the best fit line was obtained. y = 3.149 x + 0.222. The absorbance of the unknown sample was measures as 8,66. What is the concentration of the unknown sample? Answer to 2 decimal places. a) 8.56 ppm b) 2.75 ppm с) 1.66 рpm d) 2.68 ppm

A sample was analysed for its Calcium concentration. A number of standard solutions were prepared (ppm) and their absorbance values were determined. The results were plotted in Excel (concentration on x-axis and absorbance on y-axis) and the following equation for the best fit line was obtained. y = 3.149 x + 0.222. The absorbance of the unknown sample was measures as 8,66. What is the concentration of the unknown sample? Answer to 2 decimal places. a) 8.56 ppm b) 2.75 ppm с) 1.66 рpm d) 2.68 ppm

Chemistry

9th Edition

ISBN:9781133611097

Author:Steven S. Zumdahl

Publisher:Steven S. Zumdahl

Chapter4: Types Of Chemical Reactions And Solution Stoichiometry

Section: Chapter Questions

Problem 123CP: In most of its ionic compounds, cobalt is either Co(II) or Co(III). One such compound, containing...

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For the following questions (Q1-Q5), consider the compound tartrazine (Yellow 5 food dye) that has a chemical formula of C16H9N4Na3O9S2. Ana weighs out 0.1328 g of tartrazine powder on the balance for her experiment and makes a stock solution by dissolving her powder in 500.0 mL of solution. Concentration (µM or µmol/L) Absorbance 0.00 0.001 9.94 0.252 19.9 0.506 29.8 0.738 39.8 1.018 slope (m): 0.02534 1/(µM) y-intercept (b): -0.0009147 Q4. Calculate the molar extinction coefficient (molar absorptivity) of tartrazine in units of 1/(M·cm). Assume a cuvette path length of 1.00 cm.
1. A group of students from the instrumental analysis laboratory of the course analyzed the sodium content in a serum sample using ICP-OES. They used 5 flasks with 25 mL of sample serum in each and added different amounts of a standard 2.640MNaCl solution to a total volume of 50 mL . Calculate: a. Equation for calibration b. Serum sodium concentration
If the initial recorded volume titrated is 0.50 ml and the final recording is 26.95 ml, what is the total volume given a 50 ml burette?
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You measure 1.5232 g of oxalic acid on an analytical balance, add it to a 250-mL volumetric flask and add deionized H2O to a final volume of 250.0 mL. You measure 15.0 mL of the H2C2O4 solution with a 100-mL graduated cylinder and add it to a 125-mL Erlenmeyer flask. Then you add two drops of the indicator, phenolphthalein, to the oxalic acid solution in the flask. You dispense the NaOH solution from the buret into the flask (while swirling the flask) until you reach the endpoint. At the endpoint, the solution in the flask turns light pink. You repeat the titration two additional times for a total of three trials. H2C2O4 (aq) + 2 NaOH (aq) --> Na2C2O4 (aq) + 2 H2O (l) (I) (II) (III) Volume of H2C2O4 used 15.00 mL 15.00 mL 15.00 mL Molarity H2C2O4 standard solution is 0.48 M how many Moles of NaOH are there in each trial?
QUESTION 2309 A Medical Technology student was given a capsule of a multivitamins and she was asked to determine the % by mass (w/w) of ascorbic acid present in the capsule. The student analyzed the 1.032 g sample using volumetric titration. The following data was generated in the analysis: KIO3 + 5KI + 6H+ → 3I2 + 6K+ + 3H2O C6H8O6 + I2 → C6H6O6 + 2I- + 2H+ Table 1. Standardization of KIO3 Molarity of Ascorbic Acid Standard Solution 0.02612 Volume of Ascorbic Acid 25.00 mL Volume of KIO3 5.10 mL Molarity of KIO3 ______________M Table 2. Determination of Ascorbic Acid Concnetration Initial burette reading, KIO3 2.25 mL Final burette reading, KIO3 32.45 mL Volume consumed, KIO3 30.20 mL MM of Ascorbic Acid 176.12 g/mole 65.6% 54.6% 66.0% 7.30%
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Maganite is the leading brand for antacid to alleviate heartburn. Its active ingredient is a saturated solution of magnesium hydroxide (milk of magnesia) which neutralizes the sudden increase of H+ during heartburn. Its manufacturing company performed microtitration to simulate how the drug works upon intake.A 50.0 mL saturated solution was prepared. After filtering each solution, a 5.0 mL aliquot was transferred to a 25.0 mL Erlenmeyer flask and was titrated using pre-standardized 0.0320 M HCl which resembled the gastric acid. The endpoint was reached after the addition of 52.2 μL titrant.1. What is the concentration of hydroxide ions in the solution? Note: Use the scientific notation of 0.00012 = 1.2e-4 2. Determine s and Ksp of Mg(OH)2.Note: Use the scientific notation of 0.00012 = 1.2e-4
Maganite is the leading brand for antacid to alleviate heartburn. Its active ingredient is a saturated solution of magnesium hydroxide (milk of magnesia) which neutralizes the sudden increase of H+ during heartburn. Its manufacturing company performed microtitration to simulate how the drug works upon intake. A 50.0 mL saturated solution was prepared. After filtering each solution, a 5.0 mL aliquot was transferred to a 25.0 mL Erlenmeyer flask and was titrated using pre-standardized 0.0320 M HCl which resembled the gastric acid. The endpoint was reached after the addition of 52.2 μL titrant. What is the concentration of hydroxide ions in the solution? Determine solubility s.