Time left 23:51:06Question 1Not yet answeredMarked out of 2.00Flag questionQuestion textIn part B of this experiment, you will quantitatively determine the amount of aspirin, phenacetin and caffeine in an "analgesic tablet" by UV-vis absorption spectroscopy.A student is asked to perform the following procedure which is similar to the preparation of the UV-vis absorption sample in part B of PHY6:1.       Place unknown sample ‘X’ in a 200 ml volumetric flask, add 50 ml of water and 10 ml of 0.5 M KOH.  Shake until the tablet breaks up and all crystalline material has dissolved.  Dilute to 200 ml with methanol. 2.       Pipette 1 ml of this solution into a 40 ml volumetric flask and make up to 40 ml with methanol.  A blank should be prepared in the same way, which contains all reagents except the tablet.3.       Record the UV-vis absorption spectrum of this solution over the range 380-220 nm, using the blank solution to set the baselineIf, 6.83 x 10-4 mol/L of aspirin is present in the diluted sample solution used to obtain the UV-vis absorption spectrum, what is the concentration of aspirin in the undiluted stock solution?

How is the purity of the aspirin assessed in this experiment?Question 1Answerby NMR spectroscopyfrom its solubilityby infrared spectroscopyfrom the colour produced by reaction with Fe3+from its melting point

To extract caffeine, a No Doz® tablet (10 g each) was crushed and added to 100 mL of distilled water and boiled for ten minutes. Suspended solids were removed, and the supernatant was transferred to a separatory funnel. Next, 100 mL of dichloromethane (DCM, density = 1.33 g/cm³) was added to the separatory funnel, and the mixture was shaken, which resulted in the formation of two layers. Each layer was separately collected, and the aqueous layer was poured back into the separatory funnel for the extraction to be repeated. One hundred mL of DCM was added to the separatory funnel, and a second extraction was performed. After the second extraction, the layers containing caffeine from both extractions were mixed together. The resulting solution was boiled gently until a white solid formed. To determine how much caffeine was expected to dissolve in each layer and how much caffeine was extracted in total, the following formulae were used to determine the partition coefficient (Ψ) of caffeine:Ψc = [Solute] in organic layer / [Solute] in aqueous layerEquation 1 Calculation of Ψ for an extractionΨa = Ï in organic layer / Ï in aqueous layerEquation 2 Approximation of Ψ for an extractionAfter completing the extraction, recrystallization was performed. Ethanol was added to the white solid, and the solution was gently warmed and allowed to cool down to 25°C. The solution was then placed on ice until crystals formed. The crystals were vacuum filtered and tested for purity via melting point determination, IR spectroscopy, and TLC plating. In the TLC procedure, DCM was used as the solvent system, and three spots were placed on the TLC plate: crude extract, recrystallized caffeine, and a pure caffeine sample.(Note: Ϊ is the solubility of a solute in a given solvent.)Question 36Which of the following is NOT a functional group present in caffeine? A.ImideB.AmideC.Primary amineD.Tertiary amine

A standard containing ascorbic acid (25.0 mg mL-1) was analysed using reversed-phase HPLC with UV detection at 250 nm, giving a peak area of 34210.  A sample containing ascorbic acid was then analysed under the same conditions, giving a peak area of 31622.  Determine the concentration of ascorbic acid in the sample (in mg mL-1).

A second-year chemistry student is asked to make up a 500.0 mL sample of 0.057 M solution of aspirin to study the rate of hydrolysis of aspirin in the digestive system. Molar mass of Aspirin, acetylsalicylic acid, C9H8O4 = 180.17 g mol-1. (a) Calculate the mass (in grams) of aspirin that the student would need to weigh out. Provide your numerical answers and units.

1. Metronidazole plasma concentration 6 hours after administration of asingle IV dose of 400mg was 16 mg/L, and the concentration after 10hours was 8.0 mg/L. calculate the elimination rate constan