The central nervous system stimulant caffeine can be extracted from commercial No Doz® tablets. Pure caffeine has a melting point of 235°C and a density of 1.23 g/cm3. The solubility of caffeine at standard temperature is 0.14 g/mL in dichloromethane and 0.02 g/mL in distilled water.Figure 1 CaffeineTo 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 37Following the procedure of the experiment, how much total caffeine could you expect to extract? A.6.50 gB.9.84 gC.11.72 gD.12.97 g

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

What is the molecular formula for Caffeine?

Caffeine can safely be consumed in amounts greater than 500 mg/day.Group of answer choicesTrueFalse

This is a multiple answers question.Why was dichloromethane chosen as the organic solvent to be used for the extraction of caffeine from water?Group of answer choicesDichloromethane is not miscible with water.Dichloromethane has a higher solubility for caffeine than water at room temperature, i.e. 20oC.Dichloromethane has a higher solubility for caffeine than hot water.Dichloromethane is more dense than water.

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).