Answered: If the sample turned to blue or black…

If the sample turned to blue or black upon the addition of I2 solution, is the honey genuine or not? Explain your answer

Chemical Principles in the Laboratory

11th Edition

ISBN:9781305264434

Author:Emil Slowinski, Wayne C. Wolsey, Robert Rossi

Publisher:Emil Slowinski, Wayne C. Wolsey, Robert Rossi

Chapter39: Identification Of A Pure Ionic Solid

Section: Chapter Questions

Problem 3ASA

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For a Kjeldahl analysis: you weighed 0.0312 g unknown dried blood sample and digested it with concentrated H2SO4. After the distillation into boric acid solution, Methyl Purple indicator changed its color to green. During titration with 0.0110 M H2SO4 it took 15.35 mL of this H2SO4 solution to bring the color of the mixture to grey-blue. a) What number of moles of H2SO4 reacted? b) What number of moles of boric acid reacted with NH3 during distillation? c) What number of moles of NH3 was produced during distillation? d) What was mass of N in the produced NH3? e) What is %N w/w in the original sample?
you do that? Answer every possible way and why. 3) Now there are three test tubes without labels and the solutions are NazSO4, NA3PO4, and NażCO3. To determine and label, you have added Ba(NO3)2 into three solutions and found all of them turned to white precipitate and failed to discriminate. In this situation, how would you do that? 4) Cu(NO), is a blue-colored clear solution, When you determine if Cu(NO), is in an acidic or
Treatment of ammonia with phenol in the presence of hypochlorite yields indophenol, a blue product that absrobs light at 625 nm, which can be used for the spectrophotometric determination of ammonia. ocr SHN + HO- indophenol anion To determine the ammonia concentration in a sample of lake water, three samples are prepared. In sample A, 10.0 mL of lake water is mixed with 5 mL of phenol solution and 2 mL of sodium hypochlorite solution, and diluted to 25.0 mL in a volumetric flask. In sample B, 10.0 mL of lake water is mixed with 5 mL of phenol solution, 2 mL of sodium hypochlorite solution, and 2.50 mL of a 5.50 x 104 M ammonia solution, and diluted to 25.0 mL. Sample C is a reagent blank. It contains 10.0 mL of distilled water, 5 mL of phenol solution, and 2 mL of sodium hypochlorite solution, diluted to 25.0 mL. The absorbance of the three samples is then measured at 625 nm in a 1.00 cm cuvette. The results are shown in the table. Absorbance Sample (625 nm) A 0.401 В 0.648 0.045 What…
An impure sample containing 2.00 g of sodium carbonate and bicarbonate was taken. It was dissolved in water and then crushed with hydrochloric acid (0.1 N). If the burette reading was at the end point of the phenolphthalein 7.5 ml and at the end of the orange methyl point was 20.0 ml. Calculate the ratio The percentage of sodium bicarbonate in the sample. Note that the molecular weight of sodium bicarbonate is 84 *
A 0.4108-g sample of primary-standard Na2 CO3 was treated with 46.50 mL of dilute perchloric acid. The solution was boiled to remove CO2, following which the excess HCIO4 was back-titrated with 9.90 mL of dilute NaOH. In a separate experiment, it was established that 26.90 mL of the HC1O4 neutralized the NaOH in a 24.00-mL portion. Calculate the molarities of the HCIO4 and NaOH. Molarity of the HC1O4 M Molarity of the NaOH = M
An 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 CO, 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 311 mL of the standard acid. What is/are the component/s of the sample? O Cannot be determined O NAHCO3 only O NAOH and Na,CO3 O NazCO3 only O NAHCO, and Na2CO3
An 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 CO, 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. What is/are the component/s of the sample? O NazCO3 only NaHCO3 only O NAHCO3 and Na>CO3 NaOH and NazCO3 O Cannot be determined
Why is it essential that some undissolved Ca(IO3)2 remain in the solution to be measured?
Treatment of ammonia with phenol in the presence of hypochlorite yields indophenol, a blue product that absrobs light at 625 nm, which çan be used for the spectrophotometric determination of ammonia. gan OCF OH + NH3 indophenol anion To determinè the ammonia concentration in a sample of lake water, three samples are prepared. In sample A, 10.0 mL of lake water is mixed with 5 mL of phenol solution and 2 mL of sodium hypochlorite solution, and diluted to 25.0 mL in a volumetric flask. In sample B, 10.0 mL of lake water is mixed with 5 mL of phenol solution, 2 mL of sodium hypochlorite solution, and 2.50 mL of a 5.50 x 10-4 M ammonia solution, and diluted to 25.0 mL. Sample C is a reagent blank. It contains 10.0 mL of distilled water, 5 mL of phenol solution, and 2 mL of sodium hypochlorite solution, diluted to 25.0 mL. The absorbance of the three samples is then measured at 625 nm in a 1.00 cm cuvette. The results are shown in the table. Sample Absorbance (625 nm) A 0.361 B 0.608 C…
Standard solution : 0.201 grams of acetylsalicylic acid was combined with 10 mL of 0.5 M NaOH, then transfered to a 100 mL flask and filled the rest of the way with water Then 0.500 mLs of the standard solution was transfered to a 10.00 mL flask and diluted to the 10 mL mark with 0.02 M of buffered iron chloride. Number of moles of NaOH = 0.005 moles Since the reaction between acetylsalicylic acid and NaOH is a 1:1 reaction, the number of moles of acetylsalicylic acid used in the reaction is also 0.005 moles. the concentration from analysis question 5: acetylsalicylic acid in the 100.00 mL volumetric flask is 0.050 M. From your plot, what is the value of εb? From the Beer- Lambert law For the aspirin sample, calculate the concentration of acetylsalicylic acid present using the value of εb that you found The concentration from analysis question 5 represents the concentration in the 10.00 mL sample that was prepared in the volumetric flask using an aliquot of the solution in the…
1. A “barium/calcium/magnesium" unknown solution and aqueous (NH4)2SO4 produced a white precipitate that gave a green flame test. After centrifuging and decanting, the addition of aqueous (NH4)2C204 produced a white precipitate that gave a brick-red flame test. After centrifuging and decanting, the addition of aqueous NazHPO4 and NaOH gave no reaction. State the cation(s) confirmed present and absent in the unknown solution. Cation(s) present Cation(s) absent
An 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 Na,CO3 O 1.29 mmol NaOH, 0.97 mmol Na2CO3 O 0.103 mmol NaOH, 0.078 mmol NazCO3 O 1.29 mmol Na2CO3, 0.97 mmol NaHCO3 O Cannot be determined