Supersaturated Solutions Lab # 1 Name True Solutions Are .

Supersaturated SolutionsLab # 1NameTrue solutions are homogeneous mixtures of two or more pure substances, where the solute isuniformly (evenly) dispersed throughout the solvent. Solutions can be unsaturated, saturated,or supersaturated depending on the amount of solute dissolved in the solvent and thetemperature of the solution.Unsaturated Solution Less than the maximum amount of solute for that temperature is dissolved in thesolvent.Saturated Solution Solvent holds as much solute as is possible at that temperature.Supersaturated Solution Solvent holds more solute than is normally possible at a particular temperature. These solutions are unstable and crystallization can be stimulated by adding aseed crystal, scratching the side of the flask, or inserting a stirring rod.As a solution is heated, solubility of a solidsolute will increase. This is illustrated by acup of coffee with sugar. The hotter thecoffee is, the more sugar that can bedissolved into it. As the coffee cools down,excess sugar comes out of solution andsettles on the bottom of the cup.A supersaturated solution can be createdby heating a solution. Look at the diagram tothe right. The means change and indicatesthat heat is added. If a saturated solutionwith extra solute present is heated, the extrasolute will dissolve. As this solution iscooled, it becomes supersaturated. Thismeans that it holds more solute than isnormally possible at that temperature. Tomake the excess solute suddenly come outof solution and form a solid, thesupersaturated solution needs to be slightlydisturbed in some way.

PurposeThe purpose of this lab is to produce and observe asupersaturated solution through at different stages offormations or morphs.The word morphmeans changewhen it is used asa verb and formwhen it is used asa noun!Materials 5.0 g Sodium Acetate - Na(C2H3O2)Test Tube, test tube rack & test tube holder5.0 mL of Tap WaterBeakerHot PlateStirring rodProcedureA. Put 5.0 g of Sodium Acetate in the bottom of the test tube.B. Add 5.0 mL of water to the Sodium Acetate in the test tube. Use a stirring rod to stir the solution to helpdissolve as much sodium acetate as you can. Record your observations in the data table. At this point thesolution is at Morph 1.C. Heat the test tube containing the solution you have just created by placing it in a hot water bath. Heat itslowly and stir gently until the rest of the Sodium Acetate becomes dissolved. Record your observationsin the data table. At this point the solution is at Morph 2.D. When all of the Sodium Acetate is dissolved, carefully remove the test tube from the water bath. Placethe test tube in a test tube rack and leave undisturbed on the lab counter for at least 15 minutes to cool.E. After 15 minutes of cooling time have passed, carefully drop a crystal of solute into the supersaturatedsolution and observe what happens. Record your observations in the data table. At this point the solutionis at Morph 3.Data Table

Draw what is occurring in the test tube and describe it in words.Morph 1Morph 2Morph 3Analysis QuestionsUse the information in the introduction of this lab and your class notes to provide information to helpanswer the following questions.1. At Morph 1 was the solution unsaturated, saturated, or supersaturated? Explain your answer.2. At Morph 2 was the solution unsaturated, saturated, or supersaturated? Explain your answer.3. At Morph 3 was the solution unsaturated, saturated, or supersaturated? Explain your answer.4. When sodium acetate dissolves in solution, it breaks up into a positive sodium ion and a negativepolyatomic acetate ion. This separation of ions in water is called dissociation. Write a chemical equationthat shows the process for the dissociation of Sodium Acetate in water in the space below. In doing so, usebrackets and /- symbols to identify the ions.

5. During which Morph was all the Sodium Acetate fully dissociated into free moving ions?6. During which Morph(s) was the Sodium Acetate present in both a solid and dissociated form?7. Heating is important in the formation of a supersaturated solution. What does heat do to the kinetic energy in a solution? What does heat do to the speed at which ions and molecules move within a solution? As a supersaturated solution cools, what happens to the kinetic energy in the solution? As a supersaturated solution cools, what happens to the speed at which ions and water moleculesmove?8. 11The sudden changes that occur when excess solid solute comes out of a supersaturated solution arepictured below.Write a paragraph the fully describes how the supersaturated solution was formed and why the SodiumAcetate came out of the supersaturated solution.

Solubility & Conductivity Lab #2It is common knowledge that oil and water don’t mix, but do you know why? Some substances dissolve in each other andsome do not. The purpose of this lab demonstrates how a characteristic of substances called Polarity affects whethersubstances dissolve in each other. It will provide you with the basis for classifying substance with respect to their polarity byknowing only that water is a polar substance.EQUIPMENT:24-Well plateSpatula or scoopStirring-rodDisposable pipettesPaper towelsConductivity testerGogglesCHEMICALS:PRINCIPLES:Determining polar nature, solubility, and conductivityWater, H20Vegetable OilSodium chloride, Table Salt, NaClAmmonium chloride, NH4ClMethyl alcohol, Wood Alcohol, CH3OHSodium bicarbonate, Baking Soda, NaHCO3Sucrose, Table Sugar, C12H22O11Urea, NH2CONH2Chemists say that ‘like dissolves like,’ meaning that substances with similar chemical characteristics will dissolve in each other.Specifically, polar solvents tend to dissolve polar solutes, and non-polar solvents tend to dissolve non-polar solutes. Non-polarand polar liquids are insoluble. Chemists also know that some solutions conduct electricity while others do not. Those that docontain electrolytes which are ions in solution; if there aren’t any ions, the solution can’t conduct electricity.It is possible to determine the polar nature of various substances knowing that ‘like dissolves like.’ Polar substances WILL DISSOLVEin WATER (a polar solvent), while non-polar solutes DO NOT. Non-polar substances dissolve only in other non-polar materials.Determine the polarity of each item in the table by testing its solubility in water and in oil. Then determine the presence ofelectrolytes in the solutions by using the conductivity tester.PROCEDURE:Place the well plate so that 6 wells are horizontal and 4 wells are vertical.1. Carefully add distilled water to the top 6 wells across the plate. This is one of your solvents.2. Carefully add vegetable oil to the bottom 6 wells across the plate. This is one of your solvents.3. Use a spatula (for solids) add a small amount (just enough to cover the TIP of the spatula) of theitem to be tested. For liquid solutes add 2 to 3 drops.4. Add one solute to one well of water then to one well of oil. Do this for each of the 6 solutes.5. Using a glass stirring rod, mix the solutes into the solvents. Stir for up to 2 minutes. If you used toomuch solute for the small amount of solvent, you may mistakenly think the solute is insoluble!6. Check to see if the substance dissolves into the solvent to make a solution. Check for signs of solubilitysuch as the disappearance of the solute. If you are unsure, repeat step 4, and watch to see if thesubstance dissolves.7. Record your observations of solubility in the data table.8. Write whether the substance is polar or non-polar, based on your observations, in the data table.9. Dip the conductivity tester in each well to see if the solution conducts electricity. Wipe the tester offbetween each test. Record your observations in the data table.10. Carefully pour the entire contents of the well plate into the waste beakers provided by the teacher.CLEAN-UP:1. Wash out the well plate, with soap and water, then dry with a clean paper towel.2. Return all cleaned items to lab station and throw away the paper towels.Page 5of 28

Chemistry: Finding SolutionsNameStationCopyright 2011 Stevens Institute of Technology, Center for Innovation in Engineering and Science Education; Page 6 of 28; All rights reserved.DATA LDISSOLVES inH2O?DISSOLVES in OIL?POLAR orNON POLAR?ConductsElectricity?

ChemistryHS/ScienceUnit: 10 Lesson: 02Making a 1.0 Molar Solution Lab #3Solutions are used in many everyday products. The preparation of a solution requires use of aperiodic table and careful laboratory procedures. Make your calculations using dimensional analysisand significant figures.Molarity (M) is defined as the number of moles of solute divided by the number of LITERS of solution.Molarity Moles of soluteLiters of solutionProcedures for the preparation of .25 L of a 1.0 M solution of copper (II) sulfate pentahydrate: Calculate the molar mass of copper (II) sulfate pentahydrate Cu(SO4) 5H2O: g/mol How do you obtain one mole of copper (II) sulfate pentahydrate? How much water do you add to make a liter of solution? Why would using a pipette be useful when making this solution? Explain which would dissolve faster, whole crystals or crushed crystals. Use the molarity equation to calculate how many moles you will need to make 250 mL (0.25L) of 1.0 M solution of copper (II) sulfate pentahydrate. Convert moles to grams. Tell your teacher that your group is ready to make your solution. Be prepared to explain yourprocess to make this 1.0 M solution.Teacher approval grams of copper (II) sulfate pentahydrate in a 250 mL volumetric flask. Fillthe volumetric flask about half full, and swirl the flask to dissolve the solute. When all of thecopper (II) sulfate pentahydrate has dissolved, carefully fill the flask to the 250 mL mark using apipette if needed. Swirl one more time. Clean up your lab table. Pour your copper (II) sulfate pentahydrate solution into a container, asdirected by your teacher.

Solution DilutionsEach group will prepare 100 mL of a 0.25 M copper (II) sulfate pentahydrate from the 1.0 M solution youhave already prepared.Use the dilution equation: M1V1 M2V2 to calculate how much 1.0 M solution you need to make 100 mLof 0.25 M solution. Please show your work.Write your own procedures for diluting the solution.Tell your teacher that your group is ready to make your solution.Teacher approval

2. At Morph 2 was the solution unsaturated, saturated, or supersaturated? Explain your answer. 3. At Morph 3 was the solution unsaturated, saturated, or supersaturated? Explain your answer. 4. When sodium acetate dissolves in solution, it breaks up into a positive sodium ion and a negative polyatomic acetate ion.