Once cool using crucible tongs determine the mass of

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Unformatted text preview: ydrate, place the crucible with the hydrate on the clay triangle with the lid slightly ajar. Heat it slowly; if it seems to be heating too rapidly, that is, if there is splattering or too much smoke from the crucible, remove the heat, allow the crucible to cool for a minute, and resume the slow heating. Once it seems as though heating no longer causes splattering, smoke or Dakota State University Page 85 of 232 Experiment 5: Empirical Formula General Chemistry I and II Lab Manual even steam, heat the crucible vigorously until the bottom is, again, red hot. Once hot, remove the heat, put the lid fully on the crucible with crucible tongs, and allow the crucible to cool. Once cool, using crucible tongs, determine the mass of the crucible, lid and the anhydrous salt. To be sure all of the water has been driven off, repeat the step for drying the salt, and again determine the mass of the crucible, lid and anhydrous salt. If the mass of the crucible, lid and anhydrous salt is greater than 0.02 g between the two drying steps for the salt, repeat this step one more time. Dispose of the anhydrous salt as instructed to do so in lab. Dakota State University Page 86 of 232 Experiment 5: Empirical Formula General Chemistry I and II Lab Manual Observations: Mass of crucible and lid after heating 1: Mass of crucible and lid after heating 2: Mass of crucible and lid after heating 3 (if necessary): Mass of crucible, lid and hydrated salt: Mass of crucible and lid: Mass of hydrated salt: Observations: Mass of crucible, lid, and anhydrous salt after heating 1: Mass of crucible, lid, and anhydrous salt after heating 2: Mass of crucible, lid, and anhydrous salt after heating 3 (if necessary): Mass of crucible, lid and anhydrous salt: Mass of crucible and lid: Mass of anhydrous salt: Mass of water: Moles of anhydrous salt: Moles of water: Molar ratio of water to anhydrous salt: Empirical formula of compound: Dakota State University Page 87 of 232 Experiment 5: Empirical Formula General Chemistry I and II Lab Manual Calculations: From the mass of the crucible, lid and hydrated salt, and the mass of the crucible and lid after the FINAL drying step, determine the mass of the hydrated salt. From the mass of the crucible, lid and anhydrous salt and the mass of the crucible and lid, both after the FINAL drying steps, determine the mass of the anhydrous salt. From the mass of the hydrated salt and the anhydrous salt, determine the mass of the water that was driven off. From the empirical formula of the anhydrous salt provided by your lab instructor, determine the molecular mass of the anhydrous salt. From the molecular mass of this salt and the mass of the anhydrous salt, determine the moles of anhydrous salt. Similarly, determine the moles of the water. Divide the moles of water by the moles of anhydrous salt; from this, determine the empirical formula. Dakota State University Page 88 of 232 Experiment 5: Empirical Formula General Chemistry I and II Lab Manual Pre-Lab Quest...
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This note was uploaded on 09/18/2012 for the course CHEMISTRY 1010 taught by Professor Kumar during the Fall '11 term at WPI.

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