Question

The chemical 5-amino-2,3-dihydro-1,4-phthalazinedione, better known as luminol, is used by forensic scientists in analyzing crime scenes for the presence of washed-away blood. luminol is so sensitive that it can detect blood that has been diluted 10,000 times. a basic solution of luminol is often sprayed onto surfaces that are suspected of containing minute amounts of blood. luminol has a molecular weight of 177 g/mol. before investigating the scene, the technician must dilute the luminol solution to a concentration of 4.00 Ã 10â2 m . the diluted solution is then placed in a spray bottle for application on the desired surfaces. how many millimoles of luminol are present in 1.92 l of the diluted spray

Answer 1

Part A: Molar mass luminol = 177g/mol 10g = 10/177 = 0.0565 mol Luminol Dissolved in 75mL solution = 0.075L Molarity = 0.0565/0.075 = 0.753M solution Part B. There should be no problem with this part If .0L contains 3.0*10^-2 mol Luminol, then 2.0L will contain 2*3.0*10^-2 = 6.0*10^-2 mol Part C: Use equation: M1V1 = M2V2 0.753 *V1 = (3.0*10^-2) * 1000 V1 = 30/0.753 V1 = 39.8 mL of stock solution contains 3.0*10^-2 mol Luminol.