When the compounds analyzed by Robrob were passed on to the next test, another scientist, Kikoko, needed to determine the molecular weight of the ctive compound. They created a solution with a concentration of 20.0%w/w from the solid active compound and the solution had a density of 1.40 g/mL. From this solution, 10µL was taken and mixed with 190µL of reagent and water. It was analyzed and showed a concentration of 5x104 M compound. a. What is the concentration (in molarity) of the 20%w/w solution? b. Why was the concentration of the solution expressed as %w/w initially? c. What is the molecular weight of the active compound?

When the compounds analyzed by Robrob were passed on to the next test, another scientist, Kikoko, needed to determine the molecular weight of the ctive compound. They created a solution with a concentration of 20.0%w/w from the solid active compound and the solution had a density of 1.40 g/mL. From this solution, 10µL was taken and mixed with 190µL of reagent and water. It was analyzed and showed a concentration of 5x104 M compound. a. What is the concentration (in molarity) of the 20%w/w solution? b. Why was the concentration of the solution expressed as %w/w initially? c. What is the molecular weight of the active compound?

Chemistry

9th Edition

ISBN:9781133611097

Author:Steven S. Zumdahl

Publisher:Steven S. Zumdahl

Chapter11: Properties Of Solutions

Section: Chapter Questions

Problem 109AE: Patients undergoing an upper gastrointestinal tract laboratory test are typically given an X-ray...

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Patients undergoing an upper gastrointestinal tract laboratory test are typically given an X-ray contrast agent that aids with the radiologic imaging of the anatomy. One such contrast agent is sodium diatrizoate, a nonvolatile water-soluble compound. A 0.378-m solution is prepared by dissolving 38.4 g sodium diatrizoate (NaDTZ) in.l.60 102 mL water at 3 1.2C (the density of water at 31.2C is 0.995 g/cm3). What is the molar mass of sodium diatrizoate? What is the vapor pressure of this solution if the vapor pressure of pure water at 31.2C is 34.1 torr?
A 1 mL sample of glycogen was calculated to contain 21 µmol (micromole) glucose. To 1 mL of this sample was added 2 mL of 2 M HCl. It was then hydrolysed by boiling the solution for 15 minutes. After boiling the hydrolysate was cooled and made up with H2O to a final volume of exactly 10 mL. The glucose was measured in this solution and found to have a concentration of 340 µg/mL (microgram/milliliter). i) Calculate the mass (mg) of glucose in the 10 mL of hydrolysate. As the 1 mL of glycogen sample was made up to a final volume of 10 mL, this mass of glucose was produced by the hydrolysis of the original 1 mL glycogen sample. ii) Calculate the amount (µmol) of glucose produced by the hydrolysis of the glycogen sample. iii) Calculate the purity of the glycogen used in the sample as % Purity = (moles of measured glucose/ moles of calculated glucose in glycogen) *100 iv) state your answer in a complete sentence. Show your working out such that the marker can easily understand it.…
A 1 mL sample of glycogen was calculated to contain 35 µmol (micromole) glucose. To 1 mL of this sample was added 2 mL of 2 M HCL. It was then hydrolysed by boiling the solution for 15 minutes. After boiling the hydrolysate was cooled and made up with H2O to a final volume of exactly 10 mL. The glucose was measured in this solution and found to have a concentration of 570 µg/mL (microgram/milliliter). i) Calculate the mass (mg) of glucose in the 10 mL of hydrolysate. As the 1mL of glycogen sample was made up to a final volume of 10 mL, this mass of glucose was produced by the hydrolysis of the original 1 mL glycogen sample. ii) Calculate the amount (µmol) of glucose produced by the hydrolysis of the glycogen sample. iii) Calculate the purity of the glycogen used in the sample as % Purity = (moles of measured glucose/ moles of calculated glucose in glycogen) *100 iv) state your answer in a complete sentence.
Concentration of Reagents (NH4)2S2O8 KI Na2S2O3 0.25 M 0.22 M 0.19 M Volumes of Solutions S₂082 (mL) Starch soln (mL) KNO3 (mL) EDTA soln (mL) KI (mL) S₂O32- (mL) x 5 9.7 0.9 26.4 0.5 9.9 1.1 Using the above data determine the concentration of I at the moment the reaction begins. HINT: This is a mixing problem. Determine the total number of moles of I and divide this amount by the total volume (in L). Be careful... If you go back and try this exercise again the values will change. Read the question carefully! Answer:
You have a separatory funnel containing an immiscible mixture of 1-octanol (d = 0.824 g/mL) and aqueous NaOH. If you add the five compounds below and shake the funnel to mix, which compound(s) will be in which layer? LOH NH2 HO. A В C -OH D E A [ Choose ] Bottom Layer Тop Layer В TeHOuse jT [ Choose ] D [ Choose ) [ Choose ]
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A 500.00 mg vitamin C (MW176.12g/mol) tablet was ground, acidified, and dissolved in H20 to make a 250.0 mL solution. A 50.00 mL aliquot containing vitamin C, KI and starch was analyzed and titrated with 12.31 mL of 0.01042 M KIO3. What is the % (w/w) vitamin C in the tablet? KIO3 + 5 KI + 6 H* = 3 12 + 6 K* + 3 H20 C6H8O6 + 12 = C6H6O6 + 21 + 2H* %3D 3.39 % 33.89 % 67.77 % 22.59 %
• How many grans and how many mL of 40.0 wt-% urea solution (density 1.111 g/mL) are required to react with 4.00 mol of Fe3+ in the following reactions? • (H2N)2CO + 3 H2O → CO2 + 2 NH4+ + 2 OH- Fe3+ +3 OH- + (x-1)H2O - FEOOH x x H2O(s)
Tea leaves were boiled in water and around 1.50 grams of caffeine were extracted by 200.0 mL of water. If three portions of 25.0 mL of dichloromethane were used to extract the caffeine from the aqueous layer, how much caffeine will be extracted by the dichloromethane? Solubility of caffeine in water: 2.18 g per 100 mL waterSolubility of caffeine in dichloromethane: 18.2 g per 100 mL dichloromethane
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Tea leaves were boiled in water and around 1.50 gram of caffeine were extracted by 200.0 mL of water. If three portions of 25.0 mL of dichloromethane were used to extract the caffeine from the aqueous layer, how much caffeine will be extracted by the dichloromethane? Solubility of caffeine in water: 2.18 g per 100 mL waterSolubility of caffeine in dichloromethane: 18.2 g per 100 mL dichloromethane