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Unformatted text preview: I f soluble in wat er Lab #4: Whittling Down the Possibilities Purpose : To find the identity of four unknowns by determining the presence of a dipole moment, solubility in water, density relative to water, and boiling point. Part I Procedure First, presence of a dipole moment was determined. We began by rubbing a rod with a cloth to induce a charge and then, using a filled Pasteur pipette, dropping the unknown adjacent to the charged rod into a beaker. If the stream of liquid was diverted, there is a significant dipole moment. We then determined solubility by combining 0.5mL unknown and 0.5mL of water in a reaction tube and mixing the solution thoroughly by expelling and mixing with a Pasteur pipette. If the unknown is soluble (there are no distinct layers), we move onto step four. If two layers were seen, the unknown is not soluble in water. In this case, we then move on to step three. Step three consists of using a Pasteur pipette and removing the top layer of solution. We placed this solution onto a watch glass containing a mound of sodium chloride. If the salt dissolved, the top layer solution onto a watch glass containing a mound of sodium chloride....
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- Spring '08