_______1. solution a. capable of being dissolved _______2. solute
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Solutions Name: _______1. solution a. capable of being dissolved _______2. solute b. solution with water as the solvent _______3. solvent c. substance that is dissolved in a solution _______4. soluble d. substance that dissolves in water to form a solution that conducts an electric current _______5. alloy e. a solution containing two or more metals _______6. aqueous solution f. homogeneous mixture of two or more substances in a single physical state _______7. electrolyte g. substance that does the dissolving in a solution In the space provided, describe and give an example of each of the following types of solutions. 8. alloy _______________________________________________________________________ 9. liquid solution _____________________________________________________________________ 10. gaseous solution ___________________________________________________________________ _________________________________________________________________________________ Solutions Practice Circle One: 11. Which state’s streams will trout survive in better? Georgia Maine 12. Which will the fizz remain better in soda? in the refrigerator at the beach 13. Which will dissolve more sugar in your drink? ice tea hot tea 14. Does CO2 dissolve more in soda under high pressure low pressure neither 15. Does sugar dissolve more in soda under high pressure low pressure neither Beaker #1 Beaker #2 Iodine & Water Salt & Water Beaker #3 Beaker #4 Salt & CCl4 Iodine & CCl4 16. List the solute: ____________ 1 _______________ _______________ _______________ 17. List the solvent: ___________ _______________ _______________ _______________ 18. Look at the beakers above, label solutes as either ionic or molecular: ______________ _______________ _______________ _______________ 19. Look at the beakers above, label solvents as either polar or nonpolar: ______________ _______________ _______________ _______________ 20. Label which solutions will be soluble or insoluble: ______________ _______________ _______________ _______________ Interpreting Solubility Curves Name ______________________________ Date ________________ Period _________ Using the solubility graph, answer the following questions. 21. Which substance does not appear to increase greatly in solubility as the temperature is increased? ____________ 22. Which substance(s) appears to decrease in solubility as the temperature is increased? __________________________________________________________________ 23. Which substance appears to increase most in solubility as the temperature is increased? ______________ 24. Which substance is most soluble at 0C? ___________________________________ 25. Which substance is least soluble at 0C? ___________________________________ 26. Which two substances have the same solubility at 73C? _______________________ 27. What is the most KNO3 that can be dissolved at 70C? ________________________ 28. What is the most NH4Cl that can be dissolved at 70C?________________________ 29. At 70C which substance, KNO3 or NH4Cl, can form the more concentrated solution? _______________ 30. At what temperature would you need 100 g of water to dissolve 70 g of NH4Cl? __________ 31. At what temperature would you need 100 g of water to dissolve 70 g of KNO3? __________ Solubility Worksheet 32. What is the solubility of KNO3 at 30C? ____________________________________ 33. What is the solubility at KNO3 at 70C? ____________________________________ 34. Which compound varies the least in solubility over the temperature range of the graph? _________________ 35. In general, what can you say about the solubility of most solids in relationship to temperature? ___________________________________________________________________________ 36. Which compounds do not appear to follow this trend? _______________________________ 37. What change occurs in the solubility of NH3 as the temperature of the solution increases from 20C to 100C? _____________________________________________________________ 38. What is the difference between the solubilities of KNO3 and NaCl at 24C? ______________ 39. What is the difference between the solubilities of KNO3 and NaCl at 73C? ______________ 40. What type of solution will be formed if 120 grams of KI dissolved in 100 ml of water at 10C? __________________________________ 41. What type of solution will be formed if 120 grams of NaNO3 dissolve in 100 ml of water at 40C? ________________________________ 42. How many grams of NaCl are needed to make a saturated solution at 100C? ________________ 43. A saturated solution of KCl is made at 70C. 100 ml of solution is cooled to 50C and stirred. How many grams of KCl solid will appear on the bottom of the beaker? ______________ 44. At 100C, the least soluble compound is ______________________. 45. At OC, the most soluble compound is ______________________. 46. Which salt is least soluble in water at 20◦C? ________________ 47. How many grams of potassium chloride, KCl, can be dissolved in 200 g of H2O at 80◦C? __________ 48. At 40◦C, how much potassium nitrate, KNO3, can be dissolved in 300 g of H2O? ___________ 49. Which salt shows the least change in solubility from O◦C to 100◦C? __________ 50. At 30◦C, if 90 g of sodium nitrate, NaNO3, is dissolved in 100 g of H2O is this solution saturated, unsaturated or supersaturated? ________________________ 51. A saturated solution of potassium chlorate is formed in 100 g of H2O. If the saturated solution is cooled from 80◦C to 50◦C, how many grams of precipitate are formed? _____________ 52. What compound shows a decrease in solubility from 0◦C to 100◦C? ________ why? ______________ 53. Which salt is most soluble at 10◦C? ____________ 54. Which salt is least soluble at 50◦C? ____________ 55. Which salt is least soluble at 90◦C? ____________ Molarity Problems Concentration of Solutions: Complete each of the following sentences by filling in the appropriate word or phrase. Then solve each of the following problems as directed. Show all your work. 56. ___________________is the concentration of a solution expressed as the number of moles of solute dissolved in each liter of solution. 57. A ______________________ solution contains as much solute as can be possibly dissolved under existing conditions of temperature and pressure. 58. The amount of solute in a given amount of solvent or solution is the ____________________ of a solution. 59. A solution that contains more solute particles than are needed to form a saturated solution is _________________________. 60. A solution that has less than the maximum amount of solute that can be dissolved is called a(n) ___________________________ solution. 61. What is the molarity of the solution formed by mixing 0.20 mol of sodium hydroxide with enough water to make 150. ml of solution? 62. How many grams of potassium bromide should be added to water to prepare 0.50 L of solution with a molarity of 0.125 M? 63. What is the molarity of the solution produced when 145 g of sodium chloride is dissolved in sufficient water to prepare 2.75 L of solution? 64. How many grams of potassium chloride are needed to prepare 0.750 L of a 1.50 M solution of potassium chloride in water? 65. What is the molarity of the solution produced when 85.6 g of hydrochloric acid is dissolved in sufficient water to prepare 0.385 L of solution? 66. To produce 3.00 L of a 1.90 M solution of sodium hydroxide, how many grams of sodium hydroxide must be dissolved? 67. If 8.77 g of potassium iodide are dissolved in sufficient water to make 4.75 L of solution, what is the molarity of the solution? 68. In order to prepare 2.00 L of a 3.00 M solution of iron (III) chloride, how many grams of iron (III) chloride must be used? 69. What is the molarity of the solution produced when 14.1 g of ammonia (NH3) is dissolved in sufficient water to prepare 0.100 L of solution? 70. Copper (II) sulfate, an important copper salt, is used in copper electroplating cells and to kill algae in swimming pools and water reservoirs. What is the molar concentration of an electroplating solution in which 1.50 mol of copper (II) sulfate are dissolved in water to make 2.00 L of solution? 71. Sodium bicarbonate is used medicinally to counteract excess stomach acidity. How many moles of solid sodium bicarbonate would be needed to make 100. mL of 0.660 mol/L solution suitable for use as an antacid? 72. What is the molar concentration of a solution in which 0.240 mol of washing soda, Na2CO3 10H2O, is dissolved in water to make 480. mL of a solution for softening wash water? 73. A useful tile and household cleaner is (tri)sodium phosphate – (TSP). Find the number of moles of Na3PO4 in 2.00 L of a 0.100 mol/L Na3PO4(aq) cleaning solution prepared for use at home. 74. A given sample of household ammonia contains 156 g of NH3(g) dissolved in water to form 2.00 L of solution. What is the molar concentration of the household ammonia solution? 75. A rust stain remover may be prepared by dissolving potassium persulfate (K2SO5) in water. How many moles of potassium persulfate are there in 500. mL of a 0.242 mol/L solution suitable for removing dust stains? 76. What is the molar concentration of 500. mL of a solution that contains 12.7 g of swimming pool chlorinator, Ca(OCl)2? 77. A car battery terminal protective coating can be prepared by dissolving 240.0 g of sodium silicate, (Na2SiO3), in water to make 250. mL of solution. What is the molar concentration of the solution? 78. Since a saturated solution of calcium chloride does not freeze until –55 ºC, calcium chloride can be used to melt ice on roads and walks. What is the molar concentration of a saturated solution in which 3.944 kg of calcium chloride is dissolved in water to make 5.00 L of solution? 79. Sodium phosphate may be used to remove scale deposits from a car radiator. What volume of a 0.075 mol/L solution would contain the necessary 1.10 mol of sodium phosphate to remove the radiator scales? 80. Sodium thiosulfate pentahydrate, known as hypo, is used as a fixer in photography because it readily dissolves silver compounds. Describe how to prepare 100. mL of a 0.120 mol/L hypo solution. 81. A solution of sodium phosphate makes a very efficient cleaner for old brushes hardened with paint. What volume of 0.700 mol/L brush cleaning solution can be prepared from the 126 g sodium phosphate? 82. Ammonium carbonate is a suitable substitute replacement for the aqueous solution of ammonia as a household cleaning agent because it yields ammonia readily. Describe how to prepare 500. mL of a 0.450 mol/L solution of ammonium carbonate. Equilibrium Name ______________________________ Le Chatelier’s Principle Period _____________ Date ____________ 83. In a chemical reaction, a dynamic equilibrium is established when the rate of the forward reaction is _________________ to the rate of the reverse reaction, as represented by the general equation: A + B C + D 84. Now we will consider factors that disturb this equilibrium, causing either: a. the forward reaction to increase, producing a shift to the right in the equilibrium b. the reverse reaction to increase, producing a shift to the left in the equilibrium 85. Factor #1 – Concentration If more molecules of “A” are added to the system at equilibrium, then there will be more collisions between “A” molecules and the remaining “B” molecules, producing more the products, “C” and “D,” causing the equilibrium to shift to the right. 86. Suppose more molecules of “C” are added to the system: the increased number of “C” molecules can react with _______ molecules, forming more molecules of __________. 87. In other words, when more molecules of “C” are added to the system, the equilibrium shifts to the left, forming more (reactants / products). 88. In the following system: 2H2O 2H2 + O2 If more H2O is introduced, will there be (more / less) H2 and O2 formed? 89. Therefore, to relieve the stress of extra H2O, the equilibrium shifts to the (right / left) forming more (products / reactants). 90. Considering the same system used in #6, if more H2 is added to the system, which reaction is increased? (forward / reverse) 91. Therefore, to relieve the stress of extra H2, the equilibrium shifts to the (right / left). 92. Factor #2 – Pressure 93. Given: 2 A(g) + B(g) C(g) + D(g) If the above system is gaseous, in a closed container, at a constant temperature, then there are 3 volumes of reactants to every 2 volumes of products. If the pressure is increased on the system, (according to Boyle’s Law, increased pressure means ______________ volume), then the system will try to occupy a smaller volume which is accomplished by forming more products because 2 volumes occupy less space than 3 volumes. Therefore, the _____________ reaction will increase forming more C and D. 94. Conversely, if pressure is decreased, then the system will occupy a larger volume, which means the (forward / reverse) reaction will increase, forming more (products / reactants). 95. 2H2O(g) 2H2(g) + O2(g) In the above gaseous system, at constant temperature, if the pressure is increased, which reaction will increase (forward / reverse)? (More / Less) products will form; (more / less) reactants will form. 96. CO(g) + NO2(g) CO2(g) + NO(g) Suppose the pressure on the above system is increased, which will increase (products/ reactants)? 97. Factor #3 Temperature A + B C + D + heat Note that the above reaction, reading from the left to right is exothermic, i.e., it ______________ heat. Note that, reading from the right to left, the reverse reaction is endothermic, i.e., it ____________ heat. If the temperature is increased on the above system, then the reaction which absorbs or uses heat will be increased, in this case, the reverse reaction ______________. 98. 2HI H2 + I2 + heat If the temperature is increased, there be (more / less) HI formed as the result. 99. CH2OH + heat CO + 2H2 If the temperature is increased, there be (more / less) CO and H2 as a result. 99. Going back to the generalized equation in #15, if the temperature is decreased, then the reaction which produces heat is increased, in this case, the forward reaction, producing more (A and B / C and D). 100. 2 SO2 + O2 2 SO3 + heat If the temperature is decreased on the above system, which reaction increases, (forward / reverse)? There will be (more / less) SO3. 101. 2CO2 + heat 2 CO + O2 If the temperature is decreased on the above system, which reaction is increased? (forward / reverse) There will be (more / less) CO2. There will be (more / less) CO and O2? 102.These examples have been illustrations of LeChatelier’s Principle which states that a system at equilibrium, when subjected to stress, will temporarily adjust itself to relieve the stress. This means that the shift to the right or left, or the increased forward or reverse reaction, will be temporary and a new equilibrium will be reestablished. 103. Apply these principles in the following equations: 2SO2(g) + O2(g) 2SO3(g) + heat What conditions of temperature and pressure favor high equilibrium concentrations of SO3? (high / low) pressure; (high / low) temperature 104. 3 H2(g) + N2(g) 2 NH3(g) + heat The commercial production of ammonia uses the Haber Process which is expressed by the above equation. What condition of temperature and pressure will provide a maximum yield of NH3? (high / low) pressure: (high / low) temperature 105. 4HCl(g) + O2(g) 2 H2O(g) + 2 Cl2(g) + heat Increasing the temperature of the reaction will (increase / decrease) the forward reaction. Decreasing the pressure on the system will (increase / decrease) the forward reaction. LeChatelier’s Principle Fill in all blanks with increase (↑), decrease (↓), or no change (NC). Under the SHIFT column show LEFT (←) or RIGHT (→). 106. N2(g) + 3H2(g) ↔ 2NH3(g) + HEAT Stress [N2] [H2] Add N2 Increase Pressure Cool Rxn. Remove NH3 Remove H2 Add Heat Add H2 Remove N2 Add NH3 Decrease Pressure How can you make the maximum amount of NH3? [NH3] HEAT SHIFT Chart #2 Fill in all blanks with increase (↑), decrease (↓), or no change (NC). Under the SHIFT column show LEFT (←) or RIGHT (→). 107. H2(g) Stress [H2] + F2(g) ↔ [F2] Add H2 Increase Pressure Cool Rxn. Remove HF Remove F2 Add Heat Add F2 Remove H2 Add HF Decrease Pressure How can you make the maximum amount of HF? 2HF(g) [HF] H = +541 KJ HEAT SHIFT Directions: Indicate the effect of the stress on each substance in each reaction. Use the following symbols to show changes in concentration and shifts: () Increase, () Decrease, (NC) No change, () Shift to the left, () Shift to the right. 108. 4NH3(g) Stress Add O2 [NH3] + 5O2(g) 4 NO(g) + 6 H2O(g) [O2] [NO] H = -906 kJ [H2O] Shift Remove NO Remove O2 Add H 2O Decrease volume Decrease temperature 109. C2H6(g) Stress Increase volume Increase pressure Remove C2H6 Add H2 Remove C2H4 [C2H6] H2(g) + [H2] C2H4(g) [C2H4] Shift 110. PbSO 4(s) Stress + H+(aq) Pb+2(aq) + 2HSO4-(aq) [H+] [PbSO4] [Pb+2] [HSO4-] Shift Heat Shift Add PbSO4 Add H+ Remove Pb+2 Add HSO4Remove PbSO4 Remove H+ Increase pressure 111. N2(g) Stress Add N2 [N2] + 3H2(g) 2NH3(g) + [H2] [NH3] Heat Increase Pressure Cool the Mix Remove NH3 Remove H2 Add Heat 112. Given the equilibrium reaction, list 4 factors which favor a high equilibrium concentration of SO 3. SO2(g) + ½ O2(g) SO3(g) + 23 kcal Explain how each of the following can affect the rate of a reaction. 113. The nature of the reactants means ___________________________________________________ This can make the reaction slower if ___________________________________________________ This can make the reaction rate faster if ________________________________________________ 114. The temperature is equal to the ______________________________ Typically reactions proceed faster if they are ________ and proceed slower if they are ________, because there will be more __________________ if particles are moving faster. 115. The concentration of reactants means _____________________________________________ If the concentration of one of the reactants is increased the rate of the reaction will _______________ If the concentration of one of the reactants is decreased the rate of the reaction will ______________ 116. Increasing the surface area of reactants means ___________________________________________ If you increase the surface area of a reactant, the reaction will proceed _______________. If you decrease the surface area of a reactant, the reaction will proceed _______________. 117. Catalysts ________________ the rate of a reaction without being _________________. This means that catalysts are neither a __________________ nor a __________________. 118. List three ways to increase the rate at which a reactions proceeds: _________________________________________________ _________________________________________________ _________________________________________________ 119. If a reaction takes place very slowly, the bonds that are broken and reformed may be ___________ 120. If you decrease the temperature of a reaction, the molecules will move __________________. This causes the rate of the reaction to ___________________. 121. Which will react faster with water, a lump of calcium or finely powdered calcium? ______________ Explain: __________________________________________________________________________ 122. A chemical reaction rate doubles when the concentration of one reactant is doubled. Explain this in terms of the Collision Theory:________________________________________________________ _________________________________________________________________________________ 123. Catalysts lower the energy of activation by ______________________________________________ _________________________________________________________________________________ 124. Inhibitors slow down a reaction by ____________________________________________________ _________________________________________________________________________________ 125. Using the Kinetic-Molecular Theory, give two reasons why reactions occur more rapidly at high temperatures: ________________________________ ___________________________________ 126. On the energy diagram below draw a curve representing the same reaction with a catalyst. How do the activation energies differ? _________________________________________________ Does the addition of a catalyst change the final energy of the products? ___________ Explain___________________________________________________________________________ _______________________________________________________________________________ __ The Reaction Process Define each term below: 127. Collision Theory: Theory that explains how molecules must ________________with proper ____________________ and with enough _____________ in order to react. 128. Kinetic Energy: energy of ________________. This includes both ___________ and _________________ (speed and direction.) 129. Activation Energy: difference in energy from the ____________ of the diagram to the energy of the __________________. 130. Activated Complex: a _____________-lived complex formed during bond ________________ and _________________. It is neither _________________ nor ___________________. 131. The Collision Theory states that __________________ must collide in order to react. 132. A collision is effective if it leads to the formation of ________________. 133. In an effective _________________, the particles must be oriented in a favorable position that allows bonds to break and atoms to rearrange. 134. Conservation of energy means that energy is __________________ from one form to another. 135. The energy required to break bonds among reactants comes from the _______________ ________________ (motion) of the reacting particles. 136. The difference between energy at the peak of the activation diagram and the energy of the reactants is called the ____________________ ___________________. 137. When particles collide with energy equal to the activation energy, existing ___________ are disrupted and new bonds form. 138. During the transition state, the reactants form an __________________ _______________ which is short-lived and is neither reactant nor __________________. 139. The _________________ __________________ may then reform the original __________________ or form new bonds and separate into ________________________. 140. The activated complex is a very short-lived molecular complex in which the _________ are in the process of being broken and reformed. 141. Label the energy diagram to the right by placing the terms reactants and products in the appropriate locations. Indicate the activation energy with a double headed arrow. Place an “X” where the activated complex is located. How much activation energy is needed to start this reaction? ____________ Is this reaction endo or exothermic? _____________ 142. The diagram below shows the oxidation of glucose as the forward reaction. For this reaction, the activation energy hill is small. The reverse reaction, which is photosynthesis of glucose, has a higher activation energy hill. a. Which reaction requires a higher activation energy, photosynthesis or oxidation? ______________ b. Which reaction requires a net energy input, photosynthesis or oxidation? ____________________ c. Does activation energy have any effect of the net energy change of a reaction? _______ Explain. _______________________________________________________________________________
