SOLUTIONS UNIT. What composition and properties characterize a true solution(five properties)?

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1 SOLUTIONS UNIT Assignment #1 How do heterogeneous mixtures differ from homogeneous mixtures? Of the following, which are homogeneous mixtures and which are heterogeneous mixtures: black coffee, household bleach, tea, cream of mushroom soup? Name and distinguish between the two components of a solution. Explain why the dissolved component does not settle out of a solution. What composition and properties characterize a true solution(five properties)? Give a familiar example of each of these types of solutions. a. gas in liquid, b. liquid in liquid, c. solid in liquid, d. gas in gas Suppose an aqueous solution contains both sugar and salt. Can you separate either of these solutes from the water by filtration? Explain. How do hydration and solvation differ? What does hydration refer to, and what kinds of substances, ionic or molecular, does it tend to help most to become soluble in water? What four factors affect how fast a solute will dissolve in a solvent to form a What is meant by the term "polar molecule?" What is the shape of the water molecule? Explain how ionic substances dissolve in water. Why should water not be used on a grease or oil fire? Why is a solution likely to form when a polar solute and a polar solvent are combined? What factors determine the solubility of a nonpolar solid in a nonpolar liquid? "Oil and water do not mix" is an old adage. What term describes two liquids that are not mutually soluble? Why is using water to clean up a paintbrush covered with oil-based enamel not an effective cleanup method? Iodine dissolves far better in ethyl alcohol (to form "tincture of iodine") than in water. What does this tell us about molecules of ethyl alcohol, as compared with water molecules? Define miscible and immiscilbe How is solubility specified(how is is usually stated)? What is the effect of increased pressure on the solubility of gases in liquids? What is the effect of increased temperature on the solubility of solids in liquids? What is the effect of increased temperature on the solubility on gases in liquids. Distinguish between a saturated, unsaturated, and a supersaturated solution.

2 Assignment #2 Solubility Curves USE THE SOLUBILITY CURVES (at the bottom of this page) TO ANSWER THE FOLLOWING: Describe the following solutions as unsaturated, saturated, or supersaturated. a. 40 g of sodium chloride dissolved in 100 g of water at 100 o C. b. 40 g of potassium chloride dissolved in 100 g of water at 60 o C. c. 90 g of sodium nitrate dissolved in 100 grams of water at 40 o C. d. 550 g of potassium iodide dissolved in 500 g of water at 10 o C. e. 35 g of ammonia dissolved in 50 grams of water at 50 o C. How many grams of potassium chlorate must be dissolved into 100 grams of water to make a saturated solution at 70 o C? How many grams of sodium nitrate must be dissolved into 100 g of water at 50 o C to make a saturated How many grams of potassium chloride must be dissolved into 200 g of water to make a saturated solution at 80 o C? How many grams of potassium chlorate must be dissolved into 50 g of water at 40 o C to make a saturated

3 Assignment # 3 MOLARITY (M) Define the term concentration. Define the term molarity. Calculate the number of moles and the number of grams of solute in each solution. a. 1.0 L of 0.50 M NaCl b. 500 ml of 2.0 M KNO3 c. 250 ml of 0.10 M CaCl2 d. 2.0 L of 0.30 M Na2SO4 What is the molarity of a solution of silver nitrate that contains 42.5 g AgNO3 in ml of What is the molarity of a solution of sodium iodide that contains 3.75 g of NaI in L of Compute the molarities for the indicated volumes of solution. a g of Cr2(SO4)3 in 500 ml b g NH4Br in 250 ml c g CuF2 in 100 ml d g CdCl2 in 100 ml How would you prepare ml of 0.10 M potassium sulfate, K2SO4? How would prepare 50.0 ml of 0.10 M potassium thiocyanate, KSCN? Describe the preparation of each of the following solutions. a L of 4.00 M MnBr2 b L of 6.00 M LiBr c. 500 ml of 2.00 M MgBr2 d ml of 1.50 M MnSO4 Complete the following table for aqueous solutions of glucose, C6H12O6. Mass solute Moles solute Volume of solution Molarity 12.5 g 219 ml L 1.08

4 Assignment #4 Dilutions How would you prepare 100 ml of 0.40 M MgSO4 from a stock solution of 2.0 M MgSO4? You need 250 ml of 0.20 M NaCl, but the only supply of sodium chloride you have is a solution of 1.0 M NaCl. How do you prepare the required How could 50.0 ml of 4.0 M H2SO4 solution be prepared from 18.0 M H2SO4 You are asked to make 1.50 L of M HNO3 by diluting concentrated 16.0 M HNO3. What volume of the concentrated will be required to make the dilution? How much water should be used to make the new You have the following stock solutions available: 2.0 M NaCl, 4.0 M KNO3, and 0.50 M MgSO4. Calculate the volumes you must dilute to make the following solutions. a. 500 ml of 0.50 M NaCl b. 2.0 L of 0.20 M MgSO4 c. 50 ml of 0.20 M KNO3 Assignment #5 Colligative Properties of Solutions What effects will the addition of a solute have on the boiling and freezing points of a Would ocean water in which ice has been formed and then removed be a better source of salt than untreated ocean water? Explain. At the onset of arctic winter, large regions of the sea's surface freeze. Explain what happens to the freezing point of the ocean water found beneath the ice masses as winter progresses. Would spreading crystals of barium chloride on a layer on a layer of snow affect the melting process? Explain your answer. Why might calcium chloride spread on icy roads be more effective at melting ice than sodium chloride? Why would one add salt to spaghetti noodles boiling in water? Sodium hypochlorite, NaClO, is the active ingredient in liquid chlorine bleach. How does a M NaClO solution differ from a m NaClO Assignment #6 Molality (m) Calculate the molality of the following solutions. a g of NH4Cl in 4.00 X 10 2 g of water. b. 145 g of CH3ClCH3 in kg of water c g C6H12 in 231 g of benzene (C6H6) d. 157 g H2O in 1.25 kg of ethanol (C2H5OH) Calculate the molality of the following solutions. a g RbBr in 824 g of water b g SnBr2 in 1.40 X 10 2 g water c g AgClO3 in 201 g water

5 d g KF in g water Compute the mass of solute that will yield the following solutions. a. Fe2(C2O4)3 to be added to 1.00 X 10 3 g of water for a m solution. b. VOBr3 to be added to 1.00 X 10 3 g water for a m solution c. FeCl3 to g H2O for a m solution What mass of solute is needed to dissolve in the given amount of solvent to obtain the indicated solution molality? a. Br2 to 500. g CCl4 for a m solution. b. C6H6 to 100. g C7H18 for a m solution c. CCl4 to 30.0 g C6H6 for a 2.25 m solution d. C2H5OH to 750. g H2O for a 1.50 m solution.

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