Unit Exam - Solutions

Unit Exam - Solutions 1.According to Henry law, the solubility of a gas in a liquid a. depends on the liquid polarity b.remains the same as the temperature increases. c. depends on the liquid density d. Increases as the gas pressure above the liquid increases 2. When KCl dissolves in water the a. K+ ions are attracted to Cl- ions on the KCl crystal b. K+ ions are attracted to the partially negative oxygen atoms of the water molecule c. Cl- ions are attracted to the partially negative oxygen atoms of the water molecule d. K+ ions are attracted to the partially positive hydrogen atoms of the water molecule 3. A solution composed of 0.5 mole of CaBr and 100 grams of water is what percent by weight in calcium bromide ? A. 1.00 B. 5.00 C. 3.80 D. 0.500 4. In general, the solubility of ________ in water decreases as temperature increases. a. liquids b. solids c. gases d. none of these 5. The process of solute particles being surrounded by solvent particles is known as __________. a. dehydration b. agglutination c. solvation d. agglomeration 6. Which of the following will not increase the rate of solvation? a. agitating the mixture b. increase the pressure c. increasing the surface area d. increasing the temperature 7. At 90oC, the amount of CO2 that can be dissolved in water is _______ than what can be dissolved at 20oC. a. less b. more c. about the same d. dependent on the molar mass dissolved 8.According to Henry s Law, what will happen to the soluability of O2 in water if the pressure is doubled at constant temp.? a. it will double b. it will remain the same c. it will be reduced by ½ d. it will be reduced by ¼ 9. The spontaneous process whereby two gases intermingle so as to form a homogeneous mixture is known as a. osmosis b. sublimation c. condensation d. diffusion 10. The mole fraction of He in a gaseous solution prepared from 4.0 g of He, 6.5 g of Ar, and 10.0 g of Ne is __________. a. 0.20 b. 0.86 c. 0.61 d. 0.11 11. Colligative properties of a solution are the result of a. chemical properties of the solutes b. the number of dissolved solute particles c. they type of solute particles d. polarity of the solutes in solution 2. 12. The decrease in solubility of a gas in a solution when the pressure is reduced is described by ______. a. Charles s law b. The ideal gas law c. Henry s law d. Boyle s law 13.What is the name for a substance that dissolves in water but does not form ions or conduct an electric current? a. electrolyte b. nonelectrolyte c. saturated d. insoluble 14. The process of a solvent and a solute completely mixing and forming a solution is ________. a. solvation b. crystallization c. ionization d. salvation 15. What is a common means of identifying a supersaturated solution? a. dissolution b. hydration c. precipitation d. salvation 16. Under which conditions could the most He gas be dissolved in water? a. High temperature, low pressure b. High temperature, high pressure c. Low Temperature, low pressure d. Low temperature, high pressure 17.Molecular compounds that dissociate in water to form a solution are called a. colligatives b. thermic c. electrolytes d. non conductors 18. The rate of solvation of a salt in water is affected by all but which of the following? a.particle size b. boiling point c. stirring d temperature 19. In comparing the freezing point of a solution to pure water it can be observed that a. pure water freezes at a lower temp. than a solution of salt water b. the presence of salt in the water lowers the freezing point c. solute concentration has no effect on the freezing point d. the solute in water makes the ice stronger 20. Which procedure is least likely to increase the solubility of nearly all solids? a. Stirring b. Pulverizing the solid c. Heating the solution d. Increasing the pressure. 21. . A solution made by dissolving 3.4 grams of NH in sufficient water to make 2.0 liters will have what molarity ? A. 0.2 B. 0.1 C. 2.0 D. 2. a. 22. The best way to produce a super saturated solution is to a. use more solute b. stir constantly c. apply heat d. cool the solution 23. How many mols of HCl are dissolved in 60.0 mL of a 0.200 M HCl solution? 1 mol HCl = 36.5 g HCl ; 1 liter = 1000 mL a. 60.0 x 0.200 b. 0.060 x 0.200 c. 60.0 / 0.200 d. 36.5 x 0.060 x 0.200 24. Reducing the pressure in the space over a liquid will a. reduce the rate of escape of molecules from the liquid b. raise the temperature of the liquid c. lower the freezing point of the liquid D. lower the boiling point of the liquid 25. Evaporation of a solvent from a solution of a solid in a liquid causes the solution to become a. more concentrated b. more dilute c. super saturated d. unsaturated 26. Calculate the molarity of a solution made by dissolving 11.5g of solid NaOH in enough water to make 1.50 L of solution. a.1.5L b. 2.5L c. 3.0L d. .75L 27. Which of the following is not a colligative property? a. boiling point elevation b. vapor pressure lowering c. increasing solubility d. freezing point depression 3. 28.The soluability in g/100g to H2O is given for sucrose at 4 temperatures. What is the best conclusion that can b drawn from this data ,sucrose at 0oC = 179.2, at 20oC = 203.9, at 60oC = 287.3 & at 100oC = 487.2 I. all substances increase in soluability as temperature increases II. Water can hold more sucrose at 100oC than it can at 0oC III. There is a direct relationship between sucrose soluability and temperature a. only II b. I and III c. only III d. II and III 29.A single cell organism is placed in a beaker of ocean water. If protoplasm has a NaCl concentration of 1.5% and the ocean water is 4.2%, which of the following will occur? I. the organism will shrink in size II. Water will move into the organism III. The cell membrane will prevent water from entering or leaving the cell a. only I b. only II c. I and II d. II and III 30. For the most part, solutes will dissolve more quickly in hotter solvents a. True B. False 31.The greater the molality of a solution, ( the number of solute particles) the greater the increase in the boiling point. a. True b. False 32.Nonvolatile solutes are one that a. do not ionize 4. b. are non polar c. do not form gases in solution d. can not affect boiling or freezing points 33.All but which of the following are colligative properties of solutions? a. .25L b. M = .75 c. freezing point depression d. osmotic pressure 34. Osmosis is a. another name for dialysis b. the flow through a semipermeable membrane of solvent from dilute to concentrated solutions c. the flow, as above, from concentrated to dilute solutions d. the rise of liquids in tubes by capillary attraction 35.In order for solvation to occur a. solutes must separate into particles b. energy is needed to break attractive forces c. solvent particles surround solute particles d. all of these 36.The solvation process can be increased by a. causing increased collisions between the solute and solvent particles b. adding more solvent c. lowering the temperature d. all of the above 37.Sugar dissolves in water at room temperature as does table salt. With the proper set up a light bulb can be lighted by the salt solution. The reason for this is a. sugar molecules are large and interfere with the flow of electricity b. salt forms a strong ionic solution c. sugar forms an electrolytic solution d. there are more particles in the salt solution that in the sugar solution 38.All but which of the following are heterogeneous mixtures a. Suspension b. Solution c. Colloids 39.If compound A is dissolved in water, which state is true? I. Water is a solvent. II. Compound A is a colloid III. Compound A and the water comprise a solution a. I and II b. II and III c. Only I d. vegetable soup d. I and III 40. Find the concentration (M) of HCl in a solution prepared by dissolving 5.5 g of HCl in 200 g of C2H6O. The density of the solution is 0.79 g/mL. a. 21M b. 0.58M c. 6.0 × 10-4M d. 1.72M 41. Molecular compounds that dissociate in water to form a solution are called a. colligatives b. thermic c. electrolytes d. non conductors 42.The amount of sugar you put into your iced tea determines the a. coefficient of dilution b. Tyndall effect 5. c. Soluability of the tea d. None of these 43.In the process of solvation, which of the following events takes place? a. solute particles become surrounded by the solvent particles b. hydration occurs c. strong attractive forces pull the solute particles apart d. all of these occur 44.A solution contains m moles of solutes a, b and c. If you know the number of moles of a and c, you could determine the number of moles of b by using a. mole fraction b. Percent of mass formula c. Henry s Law d. the universal data table in your textbook 45.Colloids and suspensions are similar in that both __________, but are different in that _________. a. are compounds, colloids have very small particles b. heterogeneous mixtures, particles in a suspension can settle out c. are homogeneous, suspensions are types of colloids d. solutions, colloids only have one type of solute 46.The best descriptions of the substances below is I. Ocean Water II. Steel III. Air a. type of solution b. examples of types of solutions c. heterogeneous mixture d. colloidal suspensions 47.An example of a molal solution is a. 36gHCl/L b. 2.5 mol/L c. .035 M d. 0.12 m 48.If both the molarity and moles of a solution are known, it is possible to find a. molality b. mass of solute c. density of the solution d. all of these 49.Oil and water do not easily mix because a. oil is heavier than water c. oil is a compound . b. water is polar, oil is not d. water has a high specific heat 50.At 90oC, the amount of CO2 that can be dissolved in water is _______ than what can be dissolved at oC. a. less b. more c. about the same d. dependent on the molar mass dissolved 51.According to Henry s Law, what will happen to the soluability of O2 in water if the pressure is doubled at constant temp.? a. it will double b. it will remain the same c. it will be reduced by ½ d. it will be reduced by ¼ 52. The mole fraction of urea (MW = 60.0 g/mol) in a solution prepared by dissolving 16 g of urea in 39 g of H2O is __________. a. 0.37 b. 0.58 c. 0.13 d. 0.11 6. 53.The solubility in g/100g to H2O is given for sucrose at 4 temperatures. What is the best conclusion that can b drawn from this data ,sucrose at 0oC = 179.2, at 20oC = 203.9, at 60oC = 287.3 & at 100oC = 487.2 I. all substances increase in soluability as temperature increases II. Water can hold more sucrose at 100oC that it can at 0oC III. There is a direct relationship between sucrose soluability and temperature a. only II b. I and III c. only III d. II and III 54.A single cell organism is placed in a beaker of ocean water. If protoplasm has a NaCl concentration of 1.5% and the ocean water is 4.2%, which of the following will occur? I. the organism will shrink in size II. Water will move into the organism III. The cell membrane will prevent water from entering or leaving the cell a. only I b. only II c. I and II d. II and III 55.Air is a mixture of gases that is best classified as a/an a. solution b. suspension c. aerosol d. colloid 56.In a colloidal suspension, particles do not settle out of solution due to a. smaller particles are lighter and tend to float b. repulsive forces between solutes and the container c. Brownian motion causes collisions between particles of the solvent and particles of solutes d. Tyndall effect on small particles 57.Which substance is not correctly matched to the type of colloid it represents? a. blood sol b. butter -- emulsion c. smoke emulsion d. colored gem solid sol 58. We want to prepare 500. mL of 1.00 M acetic acid, CH3COOH, from a 17.5 M stock solution of acetic acid. What volume of the stock solution is required? What volume of 17.5 M acetic acid do you have to remove? a.300mL b. .075L c. 29mL d. 155 mK 59.In order for solvation to occur a. solutes must separate into particles b. energy is needed to break attractive forces c. solvent particles surround solute particles d. all of these 60. Oil does not dissolve in water because a. oil is nonpolar b. oil is polar c. oil is hydrated d. water is nonpolar e water is saturated 61. Larger pieces of a solute dissolve more slowly than small pieces a. True B. False 62. A saturated solution is a solution that a. contains the maximum amount of solute b. contains the maximum amount of solvent c. is in process of crystallizing d. contains polar molecules 63. As the pressure decreases, the solubility of gases in liquids 7. a. increases b. decreases c. decreases first then increases d. remains the same 64. How many mL of 6.0 M HCl is needed to make 250 mL of a 1.5 M HCl solution a. 625mL b. .625m L c. 62.5 mL d. .062mL 65. A supersaturated solution is one which has a. b. c. d. more solute present than solvent a superoxide dissolved in a solvent in equilibrium with undissolved solute as much solute in solution as can be dissolved under any conditions more solute dissolved than can be dissolved at equilibrium 66. Pure phenol melts at 42 C. What is the melting point of a solution of 1.0 mole of napthalene in 500 g of phenol? a. 14.8 C (K for phenol is 7.40) b. 38.9 C c. 34.6 C d. 27.2 C 67. The best way to produce a super saturated solution is to a. use more solute b. stir constantly c. apply heat d. cool the solution 68. What would be the concentration of a solution made by adding 250 mL of water to 45.0 mL of 4.2 M KOH? 0.64 M a.0.64 M b. 3.56M c. .50 M d. .07M 69. One of the following pairs do not match. The reason is (a, b, c or d) I. Colloid heterogeneous mixture with small particles that stay in suspension. II. Solutions homogeneous mixture of two or more liquids. III. Precipitate solid that forms in the bottom of a solution. a. Colloids are homogeneous mixtures b. Solutions are homogeneous mixtures of solutes in a solvent. c. Precipitates only form from a synthesis reaction. d. Colloids are types of suspensions 70. Particles in a suspension could be isolated from the solvent by a. Boiling the solution b. Filtering the solution c. Allowing the solution to sit undisturbed for a period of time. d. All of these Use the graph below to answer 71-73 71. Which solution shows a decrease in solubility as the temperature decreases? a. NaNO3 b. Ce2(SO4)3 d. NaCl 72. Which solution was least affected by a temperature increase? a. KCl b. Na/cl c. Ce2(SO4)3 d. CaCl2 73. At 40C, how many grams of salt are dissolved in Pb(NO3)2? a. 70 g b. 40 c. 75 d. 0.4 74. How many grams of KCl are dissolved in 250 g H2O at 60°C? a. 45 b. 112 c. 90 d. 216 75. Predict the solubility of KCl when the temperature is 120°C. a.62 b. 70 c. 60 d. 65