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Mass of pure acetylsalicylic acid used to prepare the 250 mL pure aspirin stock

ID: 1067880 • Letter: M

Question

Mass of pure acetylsalicylic acid used to prepare the 250 mL pure aspirin stock standard solution and the concentration (mg/mL) of this solution. (200.5 mg/250 ml)/1000 L = 0.0008 mg/L times 1000 mL = 0.8020 mg/mL Concentration (mg/ml.) and absorbance for each of the four standard acetylsalicylic acid solutions prepared C_1 V_1 = C_2 V_3 0.8020 mg/ml times 10 ml = C_2(100 ml) C_1 = 0.08 mg/ml Volume and absorbance for each of the three "unknown" aspirin tablet solutions prepared. Beer's Law plot and equation for the line (calculated using Excel). y = 6.005x + 0.017 Concentration of each "unknown" aspirin tablet solution determined using the Beer's Law plot. y = 6.005x + 0.017 C = A - B/M = 0.555 -0.017/6.005 = 0.0896 mg/ml Calculated mass of acetylsalicylic acid in the tablet for each "unknown" aspirin tablet solution prepared.

Explanation / Answer

given concentrations ( Calculated from Beer law plot)

Concentration (mg/mL)                   solution Volume(ml)                    mass (mg)= concenttation* volume

0.0896                                        10                                                       0.0896*10 =0.896

0.0548                                        6                                                       0.0548*6=0.3288

0.0313                                       4                                                         0.0313*4= 0.1252