{"id":181,"date":"2017-06-20T18:16:25","date_gmt":"2017-06-20T18:16:25","guid":{"rendered":"https:\/\/courses.lumenlearning.com\/chemistry2labs\/?post_type=chapter&p=181"},"modified":"2017-06-20T21:13:29","modified_gmt":"2017-06-20T21:13:29","slug":"lab-5-worksheet","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/chemistry2labs\/chapter\/lab-5-worksheet\/","title":{"raw":"Lab 5 Worksheet","rendered":"Lab 5 Worksheet"},"content":{"raw":"
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Download the .pdf file of the lab handout here<\/a><\/div>\r\nExperimental Procedure\r\n\r\nA. Determining the Freezing Point of Pure Solvent.\r\n
    \r\n \t
  1. Set up the Logger Pro as indicated in the introduction.<\/li>\r\n \t
  2. Fill a 600 mL beaker ~ 1\u20442 with ice. Add water just below the top of the ice level.<\/li>\r\n \t
  3. Add ~ 30 g NaCl to the ice water. This<\/li>\r\n<\/ol>\r\n<\/div>\r\n<\/div>\r\n
    \r\n
    \r\n\r\nvalue can be approximate and does not have any influcence on experimental calculations.\r\n
      \r\n \t
    1. Tarea50mLgraduatedcylinder.<\/li>\r\n \t
    2. Measureout~12mLofdeionizedwaterina graduated cylinder. Record the exactmass measured in your data section.<\/li>\r\n \t
    3. Transfer the deionized water to the testtube. Cover with either foil or a rubberstopper.<\/li>\r\n \t
    4. Insert the temperature probe so that probeis ~ 1\u20442 way into the solvent (it should not touch the bottom of the test tube) and in the middle of the test tube.<\/li>\r\n \t
    5. Place the stirrer into the solvent and ensure it will be able to agitate the solution without\u00a0bumping the temperature probe.<\/li>\r\n \t
    6. Secure the test tube apparatus to a ring stand with a clamp.<\/li>\r\n \t
    7. Once the test tube is secured, lower it so that the level of the solvent in the test tube is<\/li>\r\n<\/ol>\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n
      \r\n
      \r\n
      \r\n\r\nBELOW the level of ice water in the beaker. (Set up your apparatus as indicated in the\u00a0Figure).\r\n11. Begin recording temperature in 10 second intervals with constant agitation. (You may\u00a0need to move BOTH the temperature probe AND the stirrer to prevent the stirrer from hitting the probe). You do not need to include the temperature data in your data section until the temperature reaches ~15 \u25e6C. At that point, begin recording the data in your data section.\r\n\r\n12.The temperature will decrease until it reaches the freezing point. As long as both solid and liquid levels are present, the temperature will remain constant. Once the solution has completely frozen, the temperature will cool again. You should be able to see the freezing point as 3-4 temperature measurements that remain constant.\r\n\r\n13.When you feel you have sufficient data. Stop the temperature collection.\r\n14.Use the ring stand clamp to raise the test tube out of the ice bath so that the solvent can\u00a0thaw for Part B.\r\n15.While waiting for your solvent to thaw, graph your data (Temperature vs. Time) in the\u00a0space provided.\r\n\r\nB. Measuring the Freezing Point of the Solution (Covalent Compounds)\r\n
        \r\n \t
      1. Measure out 0.05 -0.1 g of a nonionizing unknown solute on the analytical balance. (Youneed at least 2 significant figures).<\/li>\r\n \t
      2. Transfer the unknown to the test tube and stir to dissolve.<\/li>\r\n \t
      3. Leaving the ice, pour the water from the 600 mL beaker down the drain. Add additionalice, if necessary, to ensure the beaker is still ~ 1\u20442 full of ice.<\/li>\r\n \t
      4. Add an addition ~20 grams of NaCl to the ice bath. This value can be approximate andwill not influence your calculations.<\/li>\r\n \t
      5. Lower the solution into the ice bath.<\/li>\r\n \t
      6. Begin recording temperature in 10 second intervals with constant agitation. (You mayneed to move BOTH the temperature probe AND the stirrer to prevent the stirrer from hitting the probe). You do not need to include the temperature data in your data section until the temperature reaches ~15 \u25e6C. At that point, begin recording the data in your data section.<\/li>\r\n \t
      7. When you feel you have sufficient data. Stop the temperature collection.<\/li>\r\n \t
      8. Usetheringstandclamptoraisethetesttubeoutoftheicebathsothatthesolventcanthaw for Part B.<\/li>\r\n \t
      9. While waiting for your solvent to thaw, graph your data (Temperature vs. Time) in thespace provided.<\/li>\r\n<\/ol>\r\n10.Repeat this process for a second trial by adding an additional 0.05 to 0.1 g of the same\u00a0unknown.\r\nC. Measuring the Freezing Point of the Solution (Ionic Compounds)\r\n\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n
        \r\n
        \r\n
        \r\n
          \r\n \t
        1. Clean and dry your test tube. Measure out another ~12 mL of deionized water in a graduated cylinder. Record the exact volume measured in your data section.<\/li>\r\n \t
        2. Set up your apparatus as used above.<\/li>\r\n \t
        3. Measure out 0.05 -0.1 g of an ionizing solute on the analytical balance. (You need atleast 2 significant figures).<\/li>\r\n \t
        4. Transfer the solute to the test tube and stir to dissolve.<\/li>\r\n \t
        5. Leaving the ice, pour the water from the 600 mL beaker down the drain. Add additionalice, if necessary, to ensure the beaker is still ~ 1\u20442 full of ice.<\/li>\r\n \t
        6. Add an addition ~20 grams of NaCl to the ice bath. This value can be approximate andwill not influence your calculations.<\/li>\r\n \t
        7. Lower the solution into the ice bath.<\/li>\r\n \t
        8. Begin recording temperature in 10 second intervals with constant agitation. (You mayneed to move BOTH the temperature probe AND the stirrer to prevent the stirrer from hitting the probe). You do not need to include the temperature data in your data section until the temperature reaches ~15 \u25e6C. At that point, begin recording the data in your data section.<\/li>\r\n \t
        9. When you feel you have sufficient data. Stop the temperature collection.<\/li>\r\n<\/ol>\r\n10.Use the ring stand clamp to raise the test tube out of the ice bath so that the solvent can\u00a0thaw for Part B.\r\n11.While waiting for your solvent to thaw, graph your data (Temperature vs. Time) in the\u00a0space provided.\r\n12.Repeat this process for a second trial by adding an additional 0.05 to 0.1 g of the same\u00a0solute.\r\n13.All solutions must be added to the CHM 112 Waste container in the back hood. 14.Clean the glassware and return all equipment to its proper location.\r\n\r\n<\/div>\r\n<\/div>\r\n
          <\/div>\r\n<\/div>\r\n
          \r\n
          \r\n
          \r\n\r\nPre-lab Assignment\/Questions\r\n\r\nN o t e \u2013 this pre-lab must be finished before you come to lab. (Please see syllabus for how to submit this assignment.)\r\n\r\n1. You add 0.991 g of a nonionizing solute to 10.972 grams of water. The freezing point of the solution is 3.48\u25e6 lower. The Kf of water is 1.86 \u25e6C\/m.\r\n\r\na. Determinethemolalityofthesolution.\r\n\r\nb. Calculate the molar mass of the solute.\r\n\r\n<\/div>\r\n<\/div>\r\n
          \r\n
          \r\n\r\nc. If the solute had been one that ionizes into 2 ions, what would the molar mass have been?\r\n\r\n<\/div>\r\n<\/div>\r\n
          \r\n
          \r\n\r\n2. Which of the following solutes should have the greatest impact on freezing point depression? Explain why using an equation.\r\n\r\nMgCl2\r\nKNO3\r\nGlucose (C6H12O6)\r\n\r\n<\/div>\r\n
          <\/div>\r\n<\/div>\r\n<\/div>\r\n
          \r\n
          \r\n
          \r\n\r\nExperimental Data and Results\r\n\r\n*Include all work, units and write answers in scientific notation (if applicable) using the correct number of significant figures for full credit. Obtain a signature prior to leaving lab.\r\n\r\n<\/div>\r\n<\/div>\r\n
          \r\n
          \r\n\r\nA. Determining the Freezing Point of Pure Solvent.\r\n\r\nB. Determining the Freezing Point of Solution (Covalent Compounds).\r\n\r\n<\/div>\r\n<\/div>\r\n<\/colgroup>\r\n\r\n\r\n\r\n
          \r\n
          \r\n
          \r\n\r\nMass of Solvent\r\n\r\n<\/div>\r\n<\/div><\/td>\r\n
          		<\/td>\r\n<\/tr>\r\n
          \r\n
          \r\n
          \r\n\r\nFreezing Point (From Cooling Curve)\r\n\r\n<\/div>\r\n<\/div><\/td>\r\n
          		<\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\n<\/colgroup>\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n
          <\/td>\r\n\r\n
          \r\n
          \r\n\r\nTrial 1\r\n\r\n<\/div>\r\n<\/div><\/td>\r\n
          		\r\n
          \r\n
          \r\n\r\nTrial 2\r\n\r\n<\/div>\r\n<\/div><\/td>\r\n<\/tr>\r\n
          \r\n
          \r\n
          \r\n\r\nMass of Solvent (Same for both trials)\r\n\r\n<\/div>\r\n<\/div><\/td>\r\n
          		<\/td>\r\n<\/td>\r\n<\/tr>\r\n
          \r\n
          \r\n
          \r\n\r\nMass of Unknown\r\n\r\n<\/div>\r\n<\/div><\/td>\r\n
          		<\/td>\r\n\r\n
          \r\n
          \r\n\r\n-----N\/A-----\r\n\r\n<\/div>\r\n<\/div><\/td>\r\n<\/tr>\r\n
          \r\n
          \r\n
          \r\n\r\nTotal Mass Unknown added\r\n\r\n<\/div>\r\n<\/div><\/td>\r\n
          		\r\n
          \r\n
          \r\n\r\n-----N\/A----\r\n\r\n<\/div>\r\n<\/div><\/td>\r\n
          		<\/td>\r\n<\/tr>\r\n
          \r\n
          \r\n
          \r\n\r\nFreezing Point from Cooling Curve\r\n\r\n<\/div>\r\n<\/div><\/td>\r\n
          		<\/td>\r\n<\/td>\r\n<\/tr>\r\n
          \r\n
          \r\n
          \r\n\r\n\uf044T (From Part A to Part B)\r\n\r\n<\/div>\r\n<\/div><\/td>\r\n
          		<\/td>\r\n<\/td>\r\n<\/tr>\r\n
          \r\n
          \r\n
          \r\n\r\nMolality of Solute\r\n\r\n<\/div>\r\n<\/div><\/td>\r\n
          		<\/td>\r\n<\/td>\r\n<\/tr>\r\n
          \r\n
          \r\n
          \r\n\r\nMolar Mass of Solute\r\n\r\n<\/div>\r\n<\/div><\/td>\r\n
          		<\/td>\r\n<\/td>\r\n<\/tr>\r\n
          \r\n
          \r\n
          \r\n\r\nAverage Molar Mass of Solute\r\n\r\n<\/div>\r\n<\/div><\/td>\r\n
          		<\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\n
          \r\n
          \r\n\r\nC. Measuring the Freezing Point of the Solution (Ionic Compounds) van\u2019t Hoff Factor ________________\r\n\r\n<\/div>\r\n<\/div>\r\n<\/colgroup>\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n\r\n
          <\/td>\r\n\r\n
          \r\n
          \r\n\r\nTrial 1\r\n\r\n<\/div>\r\n<\/div><\/td>\r\n
          		\r\n
          \r\n
          \r\n\r\nTrial 2\r\n\r\n<\/div>\r\n<\/div><\/td>\r\n<\/tr>\r\n
          \r\n
          \r\n
          \r\n\r\nMass of Solvent (Same for both trials)\r\n\r\n<\/div>\r\n<\/div><\/td>\r\n
          		<\/td>\r\n<\/td>\r\n<\/tr>\r\n
          \r\n
          \r\n
          \r\n\r\nMass of Unknown\r\n\r\n<\/div>\r\n<\/div><\/td>\r\n
          		<\/td>\r\n\r\n
          \r\n
          \r\n\r\n-----N\/A-----\r\n\r\n<\/div>\r\n<\/div><\/td>\r\n<\/tr>\r\n
          \r\n
          \r\n
          \r\n\r\nTotal Mass Unknown added\r\n\r\n<\/div>\r\n<\/div><\/td>\r\n
          		\r\n
          \r\n
          \r\n\r\n-----N\/A----\r\n\r\n<\/div>\r\n<\/div><\/td>\r\n
          		<\/td>\r\n<\/tr>\r\n
          \r\n
          \r\n
          \r\n\r\nFreezing Point from Cooling Curve\r\n\r\n<\/div>\r\n<\/div><\/td>\r\n
          		<\/td>\r\n<\/td>\r\n<\/tr>\r\n
          \r\n
          \r\n
          \r\n\r\n\uf044T (From Part A to Part C)\r\n\r\n<\/div>\r\n<\/div><\/td>\r\n
          		<\/td>\r\n<\/td>\r\n<\/tr>\r\n
          \r\n
          \r\n
          \r\n\r\nMolality of Solute\r\n\r\n<\/div>\r\n<\/div><\/td>\r\n
          		<\/td>\r\n<\/td>\r\n<\/tr>\r\n
          \r\n
          \r\n
          \r\n\r\nMolar Mass of Solute\r\n\r\n<\/div>\r\n<\/div><\/td>\r\n
          		<\/td>\r\n<\/td>\r\n<\/tr>\r\n
          \r\n
          \r\n
          \r\n\r\nAverage Molar Mass of Solute\r\n\r\n<\/div>\r\n<\/div><\/td>\r\n
          		<\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\n
          <\/div>\r\n<\/div>\r\n
          \r\n
          <\/div>\r\n
          \r\n
          \r\n\r\nExperimental Data and Graphs\r\n\r\nA. Determining the Freezing Point of Pure Solvent.\r\nTime Temperature Time Temperature Time Temperature\r\n\r\n<\/div>\r\n<\/div>\r\n
          \r\n
          \r\n\r\nJessica Morales. Modified from http:\/\/www.bc.edu\/schools\/cas\/chemistry\/undergrad\/genexp.html Boston College Chemistry Experiments by Lynne O'Connell is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.\r\n\r\n*Kf and Kb data from Merck Index\r\n\r\n<\/div>\r\n
          <\/div>\r\n<\/div>\r\n<\/div>\r\n
          \r\n
          <\/div>\r\n
          \r\n
          \r\n\r\nExperimental Data and Graphs\r\n\r\nB. Measuring the Freezing Point of the Solution (Covalent Compounds)\r\nTime Temperature Time Temperature Time Temperature\r\n\r\n<\/div>\r\n<\/div>\r\n
          \r\n
          \r\n\r\n*Kf and Kb data from Merck Index\r\n\r\n<\/div>\r\n<\/div>\r\n
          <\/div>\r\n<\/div>\r\n
          \r\n
          \r\n
          \r\n\r\nExperimental Data and Graphs\r\n\r\nC. Measuring the Freezing Point of the Solution (Ionic Compounds)\r\nTime Temperature Time Temperature Time Temperature\r\n\r\n<\/div>\r\n<\/div>\r\n
          \r\n
          \r\n\r\nCheck this box if all materials in your tray have been cleaned, the trays and other materials have been returned to their proper position, and all items in your drawer are accounted for.\r\n\r\nInstructor Signature_______________________________________________________________\r\n\r\n \r\n\r\n<\/div>\r\n<\/div>\r\n<\/div>\r\n
          \r\n
          \r\n
          \r\n\r\nPost Lab Questions\r\n\r\n*See this syllabus for instructions on how to turn in this section of the lab handout.\r\n
            \r\n \t
          1. A student failed to clean their test tube and had an impurity that is insoluble in water. What effect would this have on the molar mass determination (too high, too low or no change)? Explain your answer.<\/li>\r\n \t
          2. A spike in temperature is often seen when a solid is first dissolved into water. Provide an explanation for this initial increase. (See the chapter on solutions in your textbook).<\/li>\r\n \t
          3. Compare the molar mass you calculated for the unknown in Part B to the possible compounds used in Table 2. Which compound do you think your unknown was? Determine the percenterror of your calculation. \ud835\udc43\ud835\udc52\ud835\udc5f\ud835\udc50\ud835\udc52\ud835\udc5b\ud835\udc61 \ud835\udc52\ud835\udc5f\ud835\udc5f\ud835\udc5c\ud835\udc5f = \ud835\udc34\ud835\udc50\ud835\udc61\ud835\udc62\ud835\udc4e\ud835\udc59\u2212\ud835\udc38\ud835\udc65\ud835\udc5d\ud835\udc52\ud835\udc5f\ud835\udc56\ud835\udc5a\ud835\udc52\ud835\udc5b\ud835\udc61\ud835\udc4e\ud835\udc59 \ud835\udc65 100 \ud835\udc34\ud835\udc50\ud835\udc61\ud835\udc62\ud835\udc4e\ud835\udc59<\/li>\r\n \t
          4. List 2 sources of error that you could have had in Part B of this experiment. For each indicate whether the error would cause the molar mass of the solute to be calculated as too high or too low.<\/li>\r\n<\/ol>\r\n<\/div>\r\n<\/div>\r\n
            \r\n
            \r\n\r\n \r\n\r\n<\/div>\r\n<\/div>\r\n<\/div>","rendered":"
            \n
            \n
            \n
            Download the .pdf file of the lab handout here<\/a><\/div>\n

            Experimental Procedure<\/p>\n

            A. Determining the Freezing Point of Pure Solvent.<\/p>\n

              \n
            1. Set up the Logger Pro as indicated in the introduction.<\/li>\n
            2. Fill a 600 mL beaker ~ 1\u20442 with ice. Add water just below the top of the ice level.<\/li>\n
            3. Add ~ 30 g NaCl to the ice water. This<\/li>\n<\/ol>\n<\/div>\n<\/div>\n
              \n
              \n

              value can be approximate and does not have any influcence on experimental calculations.<\/p>\n

                \n
              1. Tarea50mLgraduatedcylinder.<\/li>\n
              2. Measureout~12mLofdeionizedwaterina graduated cylinder. Record the exactmass measured in your data section.<\/li>\n
              3. Transfer the deionized water to the testtube. Cover with either foil or a rubberstopper.<\/li>\n
              4. Insert the temperature probe so that probeis ~ 1\u20442 way into the solvent (it should not touch the bottom of the test tube) and in the middle of the test tube.<\/li>\n
              5. Place the stirrer into the solvent and ensure it will be able to agitate the solution without\u00a0bumping the temperature probe.<\/li>\n
              6. Secure the test tube apparatus to a ring stand with a clamp.<\/li>\n
              7. Once the test tube is secured, lower it so that the level of the solvent in the test tube is<\/li>\n<\/ol>\n<\/div>\n<\/div>\n<\/div>\n
                \n
                \n
                \n

                BELOW the level of ice water in the beaker. (Set up your apparatus as indicated in the\u00a0Figure).
                \n11. Begin recording temperature in 10 second intervals with constant agitation. (You may\u00a0need to move BOTH the temperature probe AND the stirrer to prevent the stirrer from hitting the probe). You do not need to include the temperature data in your data section until the temperature reaches ~15 \u25e6C. At that point, begin recording the data in your data section.<\/p>\n

                12.The temperature will decrease until it reaches the freezing point. As long as both solid and liquid levels are present, the temperature will remain constant. Once the solution has completely frozen, the temperature will cool again. You should be able to see the freezing point as 3-4 temperature measurements that remain constant.<\/p>\n

                13.When you feel you have sufficient data. Stop the temperature collection.
                \n14.Use the ring stand clamp to raise the test tube out of the ice bath so that the solvent can\u00a0thaw for Part B.
                \n15.While waiting for your solvent to thaw, graph your data (Temperature vs. Time) in the\u00a0space provided.<\/p>\n

                B. Measuring the Freezing Point of the Solution (Covalent Compounds)<\/p>\n

                  \n
                1. Measure out 0.05 -0.1 g of a nonionizing unknown solute on the analytical balance. (Youneed at least 2 significant figures).<\/li>\n
                2. Transfer the unknown to the test tube and stir to dissolve.<\/li>\n
                3. Leaving the ice, pour the water from the 600 mL beaker down the drain. Add additionalice, if necessary, to ensure the beaker is still ~ 1\u20442 full of ice.<\/li>\n
                4. Add an addition ~20 grams of NaCl to the ice bath. This value can be approximate andwill not influence your calculations.<\/li>\n
                5. Lower the solution into the ice bath.<\/li>\n
                6. Begin recording temperature in 10 second intervals with constant agitation. (You mayneed to move BOTH the temperature probe AND the stirrer to prevent the stirrer from hitting the probe). You do not need to include the temperature data in your data section until the temperature reaches ~15 \u25e6C. At that point, begin recording the data in your data section.<\/li>\n
                7. When you feel you have sufficient data. Stop the temperature collection.<\/li>\n
                8. Usetheringstandclamptoraisethetesttubeoutoftheicebathsothatthesolventcanthaw for Part B.<\/li>\n
                9. While waiting for your solvent to thaw, graph your data (Temperature vs. Time) in thespace provided.<\/li>\n<\/ol>\n

                  10.Repeat this process for a second trial by adding an additional 0.05 to 0.1 g of the same\u00a0unknown.
                  \nC. Measuring the Freezing Point of the Solution (Ionic Compounds)<\/p>\n<\/div>\n<\/div>\n<\/div>\n

                  \n
                  \n
                  \n
                    \n
                  1. Clean and dry your test tube. Measure out another ~12 mL of deionized water in a graduated cylinder. Record the exact volume measured in your data section.<\/li>\n
                  2. Set up your apparatus as used above.<\/li>\n
                  3. Measure out 0.05 -0.1 g of an ionizing solute on the analytical balance. (You need atleast 2 significant figures).<\/li>\n
                  4. Transfer the solute to the test tube and stir to dissolve.<\/li>\n
                  5. Leaving the ice, pour the water from the 600 mL beaker down the drain. Add additionalice, if necessary, to ensure the beaker is still ~ 1\u20442 full of ice.<\/li>\n
                  6. Add an addition ~20 grams of NaCl to the ice bath. This value can be approximate andwill not influence your calculations.<\/li>\n
                  7. Lower the solution into the ice bath.<\/li>\n
                  8. Begin recording temperature in 10 second intervals with constant agitation. (You mayneed to move BOTH the temperature probe AND the stirrer to prevent the stirrer from hitting the probe). You do not need to include the temperature data in your data section until the temperature reaches ~15 \u25e6C. At that point, begin recording the data in your data section.<\/li>\n
                  9. When you feel you have sufficient data. Stop the temperature collection.<\/li>\n<\/ol>\n

                    10.Use the ring stand clamp to raise the test tube out of the ice bath so that the solvent can\u00a0thaw for Part B.
                    \n11.While waiting for your solvent to thaw, graph your data (Temperature vs. Time) in the\u00a0space provided.
                    \n12.Repeat this process for a second trial by adding an additional 0.05 to 0.1 g of the same\u00a0solute.
                    \n13.All solutions must be added to the CHM 112 Waste container in the back hood. 14.Clean the glassware and return all equipment to its proper location.<\/p>\n<\/div>\n<\/div>\n

                    <\/div>\n<\/div>\n
                    \n
                    \n
                    \n

                    Pre-lab Assignment\/Questions<\/p>\n

                    N o t e \u2013 this pre-lab must be finished before you come to lab. (Please see syllabus for how to submit this assignment.)<\/p>\n

                    1. You add 0.991 g of a nonionizing solute to 10.972 grams of water. The freezing point of the solution is 3.48\u25e6 lower. The Kf of water is 1.86 \u25e6C\/m.<\/p>\n

                    a. Determinethemolalityofthesolution.<\/p>\n

                    b. Calculate the molar mass of the solute.<\/p>\n<\/div>\n<\/div>\n

                    \n
                    \n

                    c. If the solute had been one that ionizes into 2 ions, what would the molar mass have been?<\/p>\n<\/div>\n<\/div>\n

                    \n
                    \n

                    2. Which of the following solutes should have the greatest impact on freezing point depression? Explain why using an equation.<\/p>\n

                    MgCl2
                    \nKNO3
                    \nGlucose (C6H12O6)<\/p>\n<\/div>\n

                    <\/div>\n<\/div>\n<\/div>\n
                    \n
                    \n
                    \n

                    Experimental Data and Results<\/p>\n

                    *Include all work, units and write answers in scientific notation (if applicable) using the correct number of significant figures for full credit. Obtain a signature prior to leaving lab.<\/p>\n<\/div>\n<\/div>\n

                    \n
                    \n

                    A. Determining the Freezing Point of Pure Solvent.<\/p>\n

                    B. Determining the Freezing Point of Solution (Covalent Compounds).<\/p>\n<\/div>\n<\/div>\n\n\n\n<\/colgroup>\n\n\n\n
                    \n
                    \n
                    \n

                    Mass of Solvent<\/p>\n<\/div>\n<\/div>\n<\/td>\n

                    		<\/td>\n<\/tr>\n
                    \n
                    \n
                    \n

                    Freezing Point (From Cooling Curve)<\/p>\n<\/div>\n<\/div>\n<\/td>\n

                    		<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n\n\n\n\n<\/colgroup>\n\n\n\n\n\n\n\n\n\n\n
                    <\/td>\n\n
                    \n
                    \n

                    Trial 1<\/p>\n<\/div>\n<\/div>\n<\/td>\n

                    		\n
                    \n
                    \n

                    Trial 2<\/p>\n<\/div>\n<\/div>\n<\/td>\n<\/tr>\n

                    \n
                    \n
                    \n

                    Mass of Solvent (Same for both trials)<\/p>\n<\/div>\n<\/div>\n<\/td>\n

                    		<\/td>\n<\/td>\n<\/tr>\n
                    \n
                    \n
                    \n

                    Mass of Unknown<\/p>\n<\/div>\n<\/div>\n<\/td>\n

                    		<\/td>\n\n
                    \n
                    \n

                    —–N\/A—–<\/p>\n<\/div>\n<\/div>\n<\/td>\n<\/tr>\n

                    \n
                    \n
                    \n

                    Total Mass Unknown added<\/p>\n<\/div>\n<\/div>\n<\/td>\n

                    		\n
                    \n
                    \n

                    —–N\/A—-<\/p>\n<\/div>\n<\/div>\n<\/td>\n

                    		<\/td>\n<\/tr>\n
                    \n
                    \n
                    \n

                    Freezing Point from Cooling Curve<\/p>\n<\/div>\n<\/div>\n<\/td>\n

                    		<\/td>\n<\/td>\n<\/tr>\n
                    \n
                    \n
                    \n

                    \uf044T (From Part A to Part B)<\/p>\n<\/div>\n<\/div>\n<\/td>\n

                    		<\/td>\n<\/td>\n<\/tr>\n
                    \n
                    \n
                    \n

                    Molality of Solute<\/p>\n<\/div>\n<\/div>\n<\/td>\n

                    		<\/td>\n<\/td>\n<\/tr>\n
                    \n
                    \n
                    \n

                    Molar Mass of Solute<\/p>\n<\/div>\n<\/div>\n<\/td>\n

                    		<\/td>\n<\/td>\n<\/tr>\n
                    \n
                    \n
                    \n

                    Average Molar Mass of Solute<\/p>\n<\/div>\n<\/div>\n<\/td>\n

                    		<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
                    \n
                    \n

                    C. Measuring the Freezing Point of the Solution (Ionic Compounds) van\u2019t Hoff Factor ________________<\/p>\n<\/div>\n<\/div>\n\n\n\n\n<\/colgroup>\n\n\n\n\n\n\n\n\n\n\n
                    <\/td>\n\n
                    \n
                    \n

                    Trial 1<\/p>\n<\/div>\n<\/div>\n<\/td>\n

                    		\n
                    \n
                    \n

                    Trial 2<\/p>\n<\/div>\n<\/div>\n<\/td>\n<\/tr>\n

                    \n
                    \n
                    \n

                    Mass of Solvent (Same for both trials)<\/p>\n<\/div>\n<\/div>\n<\/td>\n

                    		<\/td>\n<\/td>\n<\/tr>\n
                    \n
                    \n
                    \n

                    Mass of Unknown<\/p>\n<\/div>\n<\/div>\n<\/td>\n

                    		<\/td>\n\n
                    \n
                    \n

                    —–N\/A—–<\/p>\n<\/div>\n<\/div>\n<\/td>\n<\/tr>\n

                    \n
                    \n
                    \n

                    Total Mass Unknown added<\/p>\n<\/div>\n<\/div>\n<\/td>\n

                    		\n
                    \n
                    \n

                    —–N\/A—-<\/p>\n<\/div>\n<\/div>\n<\/td>\n

                    		<\/td>\n<\/tr>\n
                    \n
                    \n
                    \n

                    Freezing Point from Cooling Curve<\/p>\n<\/div>\n<\/div>\n<\/td>\n

                    		<\/td>\n<\/td>\n<\/tr>\n
                    \n
                    \n
                    \n

                    \uf044T (From Part A to Part C)<\/p>\n<\/div>\n<\/div>\n<\/td>\n

                    		<\/td>\n<\/td>\n<\/tr>\n
                    \n
                    \n
                    \n

                    Molality of Solute<\/p>\n<\/div>\n<\/div>\n<\/td>\n

                    		<\/td>\n<\/td>\n<\/tr>\n
                    \n
                    \n
                    \n

                    Molar Mass of Solute<\/p>\n<\/div>\n<\/div>\n<\/td>\n

                    		<\/td>\n<\/td>\n<\/tr>\n
                    \n
                    \n
                    \n

                    Average Molar Mass of Solute<\/p>\n<\/div>\n<\/div>\n<\/td>\n

                    		<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
                    <\/div>\n<\/div>\n
                    \n
                    <\/div>\n
                    \n
                    \n

                    Experimental Data and Graphs<\/p>\n

                    A. Determining the Freezing Point of Pure Solvent.
                    \nTime Temperature Time Temperature Time Temperature<\/p>\n<\/div>\n<\/div>\n

                    \n
                    \n

                    Jessica Morales. Modified from http:\/\/www.bc.edu\/schools\/cas\/chemistry\/undergrad\/genexp.html Boston College Chemistry Experiments by Lynne O’Connell is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.<\/p>\n

                    *Kf and Kb data from Merck Index<\/p>\n<\/div>\n

                    <\/div>\n<\/div>\n<\/div>\n
                    \n
                    <\/div>\n
                    \n
                    \n

                    Experimental Data and Graphs<\/p>\n

                    B. Measuring the Freezing Point of the Solution (Covalent Compounds)
                    \nTime Temperature Time Temperature Time Temperature<\/p>\n<\/div>\n<\/div>\n

                    \n
                    \n

                    *Kf and Kb data from Merck Index<\/p>\n<\/div>\n<\/div>\n

                    <\/div>\n<\/div>\n
                    \n
                    \n
                    \n

                    Experimental Data and Graphs<\/p>\n

                    C. Measuring the Freezing Point of the Solution (Ionic Compounds)
                    \nTime Temperature Time Temperature Time Temperature<\/p>\n<\/div>\n<\/div>\n

                    \n
                    \n

                    Check this box if all materials in your tray have been cleaned, the trays and other materials have been returned to their proper position, and all items in your drawer are accounted for.<\/p>\n

                    Instructor Signature_______________________________________________________________<\/p>\n

                     <\/p>\n<\/div>\n<\/div>\n<\/div>\n

                    \n
                    \n
                    \n

                    Post Lab Questions<\/p>\n

                    *See this syllabus for instructions on how to turn in this section of the lab handout.<\/p>\n

                      \n
                    1. A student failed to clean their test tube and had an impurity that is insoluble in water. What effect would this have on the molar mass determination (too high, too low or no change)? Explain your answer.<\/li>\n
                    2. A spike in temperature is often seen when a solid is first dissolved into water. Provide an explanation for this initial increase. (See the chapter on solutions in your textbook).<\/li>\n
                    3. Compare the molar mass you calculated for the unknown in Part B to the possible compounds used in Table 2. Which compound do you think your unknown was? Determine the percenterror of your calculation. \ud835\udc43\ud835\udc52\ud835\udc5f\ud835\udc50\ud835\udc52\ud835\udc5b\ud835\udc61 \ud835\udc52\ud835\udc5f\ud835\udc5f\ud835\udc5c\ud835\udc5f = \ud835\udc34\ud835\udc50\ud835\udc61\ud835\udc62\ud835\udc4e\ud835\udc59\u2212\ud835\udc38\ud835\udc65\ud835\udc5d\ud835\udc52\ud835\udc5f\ud835\udc56\ud835\udc5a\ud835\udc52\ud835\udc5b\ud835\udc61\ud835\udc4e\ud835\udc59 \ud835\udc65 100 \ud835\udc34\ud835\udc50\ud835\udc61\ud835\udc62\ud835\udc4e\ud835\udc59<\/li>\n
                    4. List 2 sources of error that you could have had in Part B of this experiment. For each indicate whether the error would cause the molar mass of the solute to be calculated as too high or too low.<\/li>\n<\/ol>\n<\/div>\n<\/div>\n
                      \n
                      \n

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