CHEM 053 Lecture Notes - Lecture 7: Aspirin, Reagent, Absorbance
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Look at objectives (student should be able to) Ex: using funnels, spectroscopy, write a reaction equation. Before: clean and replace all pieces from your drawer this week. Write procedure for first half of aspirin lab, review two others- 10 pts. What we"re looking at: solvents (hopefully all excess water evaporated- take mass again) , unreacted sm. If purple, some sal acid is still in there. If wavelength absorbed was between 500-550 nm (absorbed green light) the thing itself is red. Emission: color of object measured is same as readout. Abs: color of object is opposite of readout. Absorbance = molar absorptivity x lath length x concentration. Measure max wavelength on each graph of 45 solutions of known concentration. We"re trying to measure the amount of salicylic acid in product. Serial dilutions-- start with stock, add water to get 2, add more water to get 3, etc.
