In 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?Undiluted [aspirin] = Answer 1 Question 1 mol/L (Give your answer to 3 significant figures in scientific notation i.e. 1.23E-4).

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

Oh no! A chemist has bumped their head into a doorway in the lab and has developed a mild headache. Annoyed by this headache, they decide to take two aspirin tablets to relieve the pain. Aspirin is also known as acetylsalicylic acid (C9H8O4), which is a weak monoprotic acid with a pKa of 3.5. Each aspirin tablet contains 500 mg of aspirin. The two tablets are dissolved into 390 mL of water in a glass - to two decimal places, what is the pH of this solution?

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).

Which of the following typical clinical biochemical tests make use of the increased absorbance at 340 nm by NADH?Question 4Answera.Acid phosphatase and carbohydrate deficient transferrinb.Lactate dehydrogenase and aspartate aminotransferasec.Creatine kinase and gamma glutamyl transferased.Alkaline phosphatase and aspartate aminotransferasee.Alanine aminotransferase and gamma glutamyl transferase