Forensic Chemical Analysis: What is this solid!? Name______________________ No criminal is so clever that he or she never leaves a trace: this is the guiding principle of forensic scientists. Forensic Science is the use of science to analyze evidence to determine what happened, where something happened, when something happened and who was involved. The analyzed evidence is then used in criminal or civil courts of law. Those who study forensics use multiple sciences to accomplish such a task. Chemistry, which is sometimes described as the “central science,” is extremely important in forensics. Last night the lab was broken into and most of the test tubes were stolen! All that was left behind was a draw full of pens and a pile of white powder. The ransom note will be analyzed next week. This week, the goal is to identify the white powder. We know that other labs in the area have had solids such as these stolen and we want to link this crime to the others. We know that the following compounds are the most likely: sodium acetate: NaCH3CO2 sodium hydrogen carbonate: NaHCO3 oxalic acid: H2C2O4 potassium hydrogen phthalate: HKC8H4O4 oxalic acid is a diprotic acid with Ka1 = 6.5 x 10-2 and Ka2 = 6.1 x 10-5 potassium hydrogen phthalate is a weak acid with Ka = 3.9 x 10-6 Your lecture materials give you the acid/base properties and constants for the other two solids. Procedure Your goal is to determine which of these four solids your sample is. The way you do it is basically up to you. You are provided with the following: approximately 0.1 M NaOH solution approximately 0.1 M HCl solution pH meter burette balance Reminder 1: pH meters are not terribly accurate. Reminder 2: The tap water is often either a bit acidic or basic. As such, you cannot use the simple pH of a solution of the solid to determine which it is. Reminder 3: The lowest molar mass is around 50 g/mol. Use this and the concentration of HCl or NaOH to determine how much to use in any test. Check with your instructor to make sure.Yours to decide. Which solid is present?_________________________Forensic Chemical Analysis: What is this solid!?