2 what similarities do you notice in the salts used

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Unformatted text preview: probe in the solution. Record the temperature when the solution first begins to boil. Calculate the value of “i” for each substance. Calculations: Colligative properties: Dakota State University page 170 of 232 Experiment 16: Colligative Properties General Chemistry I and II Lab Manual The equation for boiling point elevation is ∆Tb=iK b m, where m is molality (moles of solute per kilogram of solvent), and for water, the boiling point elevation constant, Kb, is 0.512 o C/m. Dakota State University page 171 of 232 Experiment 16: Colligative Properties General Chemistry I and II Lab Manual Observations: Diffusion: Observations: Solubility of Ammonia: Observations: Dakota State University page 172 of 232 Experiment 16: Colligative Properties General Chemistry I and II Lab Manual Solubility Solute Sodium Chloride Calcium Phosphate Sugar Naphthalene Ethylene Glycol Paraffin Oil Hexane Water Low Temperature High Temperature Observations: Temperature and solubility: Solute Potassium Nitrate Sugar Ethylene Glycol Observations: Dakota State University page 173 of 232 Experiment 16: Colligative Properties General Chemistry I and II Lab Manual Colligative Properties: Solute KNO3 sugar ethylene glycol Dakota State University Boiling Point Value of “i” page 174 of 232 Experiment 16: Colligative Properties General Chemistry I and II Lab Manual Name: Date: Solubility and Colligative Properties Pre-Lab Questions 1) List the salts we are using in part one and label them as polar or non-polar. 2) What similarities do you notice in the salts used in the effect of temperature on solubility? What differences? 3) What Colligative property are we studying? Dakota State University page 175 of 232 Experiment 16: Colligative Properties General Chemistry I and II Lab Manual Solubility and Colligative Properties Post-Lab Questions 1) Do you expect that cooking oil is polar or non-polar? Explain your reasoning. 2) What did you notice about the freezing point depression? Can you explain it? 3) Look at the compounds we used for boiling point elevation and the value of “i” that you calculated for each. What do you suppose “i” stands for? Dakota State University page 176 of 232 Experiment 17: Calorimetry General Chemistry I and II Lab Manual Experiment 17: calorimetry Purposes: To measure heat transfer Ping: A noise made by expensive machines in operating rooms to impress the administration Background: See “Using the Pasco System” and “Basic Laboratory Procedures”; pipettes, balance Introduction: Ever wonder how it is that scientists come to draw the conclusions that have put science where it is today? Today’s experiment is split into two parts; the first is designed to get you to practice asking questions, blind, as it were, much as scientists were a hundred years ago. Nowadays, it is easy to draw on the conclusions of scientists gone by, Dalton’s atomic theory, the Bohr atom, as convenient starting points. But, what do you do if you have no convenient starting point? Then the starting point becomes the most basic; pure observation. The next part of the experiment has several purposes; among them are t...
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