A 5.00 mL sample of filtered orange juice was treated with 50.00 mL of 0.01019 M I3– to oxidize ascorbic acid to dehydroascorbic acid. After the oxidation was complete, excess I3– was back- titrated with 13.96 mL of 0.07125 M Na2S2O3 to starch indicator endpoint. What is the concentration of ascorbic acid (MM = 176.12) in the orange juice? Report the concentration ascorbic acid in mg/100mL. C6H8O6 + I3– → C6H6O6 + 3I- + 2H+ I3– + 2S2O32- → S4O62- + 3I2

A 5.00 mL sample of filtered orange juice was treated with 50.00 mL of 0.01019 M I3– to oxidize ascorbic acid to dehydroascorbic acid. After the oxidation was complete, excess I3– was back- titrated with 13.96 mL of 0.07125 M Na2S2O3 to starch indicator endpoint. What is the concentration of ascorbic acid (MM = 176.12) in the orange juice? Report the concentration ascorbic acid in mg/100mL. C6H8O6 + I3– → C6H6O6 + 3I- + 2H+ I3– + 2S2O32- → S4O62- + 3I2

Introductory Chemistry: An Active Learning Approach

6th Edition

ISBN:9781305079250

Author:Mark S. Cracolice, Ed Peters

Publisher:Mark S. Cracolice, Ed Peters

Chapter22: Biochemistry

Section: Chapter Questions

Problem 68E

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A 5.00 mL sample of filtered orange juice was treated with 50.00 mL of 0.01019 M I3– to oxidize ascorbic acid to dehydroascorbic acid. After the oxidation was complete, excess I3– was back- titrated with 13.96 mL of 0.07125 M Na2S2O3 to starch indicator endpoint. What is the concentration of ascorbic acid (MM = 176.12) in the orange juice? Report the concentration ascorbic acid in mg/100mL. C6H8O6 + I3– → C6H6O6 + 3I- + 2H+ I3– + 2S2O32- → S4O62- + 3I2 A. 82.51 % B. 42.89 % C. 27.34 % D. 40.85 %
2.0 g of mixture involving Na3PO4, Na2HPO4 or NaH2PO4 or involving three of them. The solution is titrated with 16.5 mL of 0.5 M HCl to reach bromocresol green end point. The same solution is also titrated with 7.6 mL of 0.7 M NaOH to reach phenolphthalein end point. What is the composition of that mixture? What are the amounts of species (%) in the mixture (H:1.0078, O:15.99, Na: 22.98, P:30.974)?
The amount of ascorbicacid ,in aorange juice was determined by oxidzing the ascorbic acid to dehydroascorbic acid , with a known excess I3 , and back titrating the excess I3 with na2s3o4. A 5 ml sample of filtered orange juice was treated with 50ml of excess 0.01023mol/l. After the oxidation was complete, 13,72 ml of 0,07203 mol/l na2s204 was needed to reach the starch indicator end point. Report the concentration acid in miligrams per 100ml
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A biochemist completely digests a glycerophospholipid with a mixture of phospholipases A and D. HPLC and mass spectrometry analysis reveals the presence of an amino acid of 105,09 Da, a saturated fatty acid of 256.43 Da, and an omega-3 monounsaturated fatty acid of 282.45 Da. Which amino acid does the glycerophospholipid contain? O valine (C,H, NO,) O alanine (C, H,NO,) O scrine (C,H,NO,) O proline (C,H,NO,) Modify the phosphoglycerol backbone to draw the most likely structure of the lipid. Add the amino acid using the groups tool. Draw Rings Groups More Erase Select
A 0.9134-g of KIO3 is dissolved in 500-mL distilled water. A 50.0-mL aliquot portion was run down into an Erlenmeyer flask and 2-g of KI and 2-mL of 6M HCl were added to it. Directly after, the solution was titrated with a 24.47-mL Na2S2O3 solution to a faint yellow solution. Starch TS was added to the resulting solution and the titration with the Na2S2O3 solution continued wherein an additional 1.33-mL was required to bring the blue color of the solution to disappear completely. MW: KIO3 = 214.0 g/mol ; Na2S2O3 = 158.1 g/mol Compute the M of the Na2S2O3 solution. 0.1047 M None of the choices 0.1107 M 0.09926 M
A glycylglycine buffer is made to a pH of 8.45 at 25 ∘C then warmed to 37 ∘C. The pH of the solution changes because of the pKa changes. Glycylglycine has a p?a=8.26 and a Δp?a/Δ?=−0.026 °C−1. Calculate the pH of the buffer at 37 ∘C.
The thiourea in a 1.455-g sample of organic material was extracted into a dilute H2SO4 solution and titrated with 37.31 mL of 0.009372 M Hg2+ via the reaction. Calculate the percent (NH2)2CS (76.12 g/mol) in the sample. 4 (NH2)2CS + Hg2+ → [(NH2)2CS]4Hg2+
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(a) (i) Write an equation showing the formation of a triacylglycerol (Molecule A) thatcontains equimolar amounts of myristoleic, capric and linolenic acids. Myristoleic acid: CH3(CH2)5CH=CH(CH2)7CO2HCapric acid: CH3(CH2)8CO2HLinolenic acid: CH3CH2(CH=CHCH2)3(CH2)6CO2H (ii) Draw the structure of the partially hydrogenated product of Molecule A.
Balance the following chemical equation (if necessary) for the synthesis of aspirin from salicylic acid and acetic anhydride shown below: C7H6O3 + C4H6O3 -> C9H8O4 + C2H4O2