workbook-20231217054856310070-Organic-Compounds-Practice-f

An environmental chemist working for the Environmental Protection Agency (EPA) was directed to collect razor clams from a heavily-contaminated river superfund site and analyze them for their Cd?+ content using graphite furnace atomic absorption spectrometry (GFAAS). The chemist dried the clams at 95 °C overnight and ground them in a scientific blender, resulting in approximately 50 g of homogenized dry weight. A representative 98.75 mg sample was taken from the approximately 50 g of dry material and dissolved in 100.0 mL of 0.1 M HCI to create a sample solution. Using the method of standard additions, the chemist prepared five standard solutions in 100.0 mL volumetric flasks, each containing 5.00 mL aliquots of the sample solution. Varying amounts of a 75.0 ppb (ug/L) Cd? + standard were added to each of the flasks, which were then brought to volume with 0.1 M HCI. The Cd? + content of the solutions was then analyzed using GFAAS, resulting in the. absorbance data given in the table.…

professor Scimemi has accepted you as a Master’s student and you are involved in a project that studies the cellular basis of neuropsychiatric diseases. For your electrophysiology recordings you have to make a recording solution containing (in mM): 119 NaCl, 2.5 KCl, 2.5 CaCl2, 1 MgCl2, 26.2 NaHCO3, 1 NaH2PO4, 22 glucose. You need 800 ml of it. How much KCl do you need to weigh out? Hint: we only care about KCl here. (MW KCl is 74.55 g/mol