2nd Semester Exam Review. C. K eq = [N 2][H 2 ]

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1 Name: ate: 1. Which pair of formulas represents the empirical formula and the molecular formula of a compound?. H 2 O, 4 H 6 O 4. HO, 6 H 12 O 6 8. Given the reaction at equilibrium: N 2 (g) + 3H 2 (g) 2NH 3 (g) The correct equilibrium expression for this reaction is. H 4, 5 H 12. H 2, 3 H 6 2. compound contains 40% calcium, 12% carbon, and 48% oxygen by mass. What is the empirical formula of this compound?. K eq = [NH 3] 2 [N 2 ][H 2 ]. K eq = [N 2][H 2 ] [NH 3 ]. K eq = [N 2][H 2 ] [NH 3 ] 2. K eq = [NH 3] 2 [N 2 ][H 2 ] 3. ao 3. a 2 O 4. a 3 O 6. ao 2 3. compound contains 0.5 mole of sodium, 0.5 mole of nitrogen, and 1.0 mole of hydrogen. The empirical formula of the compound is. NaNH. Na 2 NH. NaNH 2. Na(NH) 2 4. Which is an empirical formula?. H. 2 H 2. 2 H 4. 4 H 8 9. Given the system at equilibrium: gl(s) g + (aq) + l (aq) When 0.1 M Hl is added to the system, the point of equilibrium will shift to the. right and the concentration of g + will decrease. right and the concentration of g + will increase. left and the concentration of g + (aq) will decrease. left and the concentration of g + (aq) will increase 5. n atom represented by X forms a compound with the formula X 3 N 2. The atom could be. Na. Mg. l. s 6. What is the molecular formula of a compound that has a molecular mass of 42 and an empirical formula of H 2?. H 2. 2 H 4. 3 H 6. 4 H Given the reaction at equilibrium: 10. Which reaction has the equilibrium expression K = [][]2 [ 2 ]. 2 (g) (g) + 2(g). 2(g) (g) + 2 (g). (g) + 2(g) 2 (g). (g) + 2 (g) 2(g) 11. In the potential energy diagram, which letter represents the potential energy of the activated complex?....? (g) + (g) + heat (g) + (g) The equilibrium will shift to the right when the. pressure is decreased. temperature is increased. concentration of (g) is decreased. concentration of (g) is increased 12. The addition of a catalyst to a reaction will cause a change in the. potential energy of the reactants. potential energy of the products. heat of reaction. activation energy page 1

2 13. In order for a chemical reaction to occur, there must always be. an effective collision between reacting particles. a bond that breaks in a reactant particle. reacting particles with a high charge. reacting particles with a high kinetic energy 14. Which arrow represents the activation energy for the forward reaction? Why can an increase in temperature lead to more effective collisions between reactant particles and an increase in the rate of a chemical reaction?. The activation energy of the reaction increases.. The activation energy of the reaction decreases.. The number of molecules with sufficient energy to react increases.. The number of molecules with sufficient energy to react decreases. 18. The potential energy diagram for a chemical reaction is shown below The minimum amount of energy required to start a chemical reaction is called. entropy. enthalpy. free energy. activation energy 16. potential energy diagram is shown. Each interval on the axis labeled Potential Energy (kj) represents 40 kilojoules. What is the heat of reaction?. 120 kj. 40 kj. +40 kj kj 19. s two chlorine atoms combine to form a molecule, energy is. absorbed. released. created. destroyed 20. Given the reaction: Which letters represent the activation energy of the forward and reverse reactions, respectively?. and. and. and. and a + 2H 2 O a(oh) 2 + H 2. How many moles of H 2 O are needed to exactly react with 2.0 moles of a? In the reaction N 2 + 3H 2 2NH 3, how many grams of H 2 are needed to produce exactly 1 mole of ammonia?. 1 g. 2 g. 3 g. 4 g page 2

3 22. Given the reaction: 2 2 H O 2 + 6H 2 O What is the total number of O 2 molecules produced when one mole of 2 H 6 is consumed? ( ). 3( ). 4( ) 23. Given the reaction: 8 H 16+12O2 8O 2 + 8H 2 O How many moles of H 2 O are produced when 11.2 liters of 8 H 16 gas, measured at STP, reacts completely? In the reaction Fe 2 O 3 + 3O 2Fe + 3O 2, what is the total number of moles of O used to produce 112 grams of iron? Given the reaction: N 2 (g) + 3H 2 (g) 2NH 3 (g). What is the ratio of moles of H 2 (g) consumed to moles of NH 3 (g) produced?. 1 : 2. 2 : 3. 3 : 2. 6 : Given the reaction at STP: 2KlO 3 (s) 2Kl(s) + 3O 2 (g) What is the total number of liter of O 2 (g) produced from the complete decomposition of mole of KlO 3 (s)? 30. Which solution contains the greatest number of moles of solute?. 0.5 L of 0.5 M. 0.5 L of 2 M. 2 L of 0.5 M. 2 L of 2 M 31. How many grams of ammonium chloride (gram formula mass = 53.5 g) are contained in L of a 2.00 M solution? g g g. 107 g 32. The molarity (M) of a solution is equal to the.... number of grams of solute liter of solvent number of grams of solute liter of solution number of moles of solute liter of solvent number of moles of solute liter of solution 33. The data shown were collected at the endpoint of a titration performed to find the molarity of an Hl solution. What is the molarity of the acid solution? Volume of acid (Hl) used = 14.4 ml Volume of base (NaOH) used = 22.4 ml Molarity of standard base (NaOH) = 0.20 M. 1.6 M M M M L L L L 27. Given the reaction: 2 2 H 2 (g) + 5O 2 (g) 4O 2 (g) + 2H 2 O(g) What is the total number of grams of O 2 (g) needed to react completely with 0.50 mole of 2 H 2 (g)?. 10 g. 40 g. 80 g. 160 g 28. What is the molarity of a solution that contains 0.25 mole of solute in 250 milliliters of solution? 34. The total number of sodium atoms in 46.0 grams of sodium is What is the total number of hydrogen atoms in one mole of H 3 OH? M M M M 36. Which represents the greatest mass of chlorine? 29. How many moles of H 2 SO 4 are needed to prepare 5.0 liters of a 2.0 M solution of H 2 SO 4?. 1 mole of chlorine. 1 atom of chlorine. 1 gram of chlorine. 1 molecule of chlorine page 3

4 37. ccording to the rrhenius theory, a substance that yields hydrogen ions as the only ion in an aqueous solution is. a salt. a base. an acid. a nonelectrolyte 38. If Hl and H 2 O react together in an acid-base reaction to form their rönsted-lowry conjugates, the products would be. Hl and H 3 O +. l and OH. l 2 and H 2. l and H 3 O Which statement best describes a solution with a ph of 3?. It has an H 3 O + ion concentration of mol/l and is acidic.. It has an H 3 O + ion concentration of mol/l and is acidic.. It has an H 3 O + ion concentration of mol/l and is basic.. It has an H 3 O + ion concentration of mol/l and is basic. 45. Which ph value represents a solution with the lowest OH ion concentration? 39. Equal volumes of 0.5 M Hl and 0.5 M NaOH are mixed. The total volume of the resulting mixture is 2 liters. The ph of the resulting solution is The ph of a 0.1 M H 3 OOH solution is. less than 1. greater than 1 but less than 7. equal to 7. greater than M Hl solution differs from a 0.1 M NaOH solution in that the Hl solution What is the H + ion concentration of an aqueous solution that has a ph of 11? mol/l mol/l mol/l mol/l 47. What is the H + ion concentration of an aqueous solution in which the OH ion concentration is mole per liter? M M M M 48. cidic solutions are those that contain an excess of. has a lower ph. turns litmus blue. contains H 3 O + ions. does not contain OH. H 2 molecules. H 2 O molecules. H + ions. OH ions 42. In a solution, litmus is blue. The ph of the solution could be If a solution has a hydronium ion concentration of M, the solution is. basic and has a ph of 9. basic and has a ph of 5. acidic and has a ph of 9. acidic and has a ph of If an aqueous solution turns blue litmus red, which relationship exists between the hydronium ion and hydroxide ion concentration?. [H 3 O + ] > [OH ]. [H 3 O + ] < [OH ]. [H 3 O + ] = [OH ] = [H 3 O + ] = [OH ] = milliliter sample of Hl solution is exactly neutralized by 6.0 milliliters of a 3.0 M NaOH solution. What is the concentration of the Hl solution?. 1.0 M. 2.0 M. 1.8 M. 1.5 M 51. s the average kinetic energy of a substance increases, the temperature of the sample. decreases. increases. remains the same page 4

5 52. s heat is added to a liquid that is boiling at constant pressure, the temperature of the liquid 57. Which of the following best describes exothermic chemical reactions?. decreases. increases. remains the same. They never release heat.. They always release heat.. They never occur spontaneously. 53. Which statement is true concerning the reaction N(g) + N(g) N 2 (g) + energy?. They always occur spontaneously.. bond is broken and energy is absorbed.. bond is broken and energy is released. 58. ccording to the potential energy diagram shown for the reaction + +, the activation energy is highest for the. bond is formed and energy is absorbed.. bond is formed and energy is released. 54. When 10 grams of a compound was dissolved in 100 grams of water, the temperature of the water rose from 25 to 30. For each gram of compound dissolved, how many calories of heat were absorbed by the water?. 5 cal. 10 cal. 50 cal. 100 cal 55. What is the total amount of heat energy, in joules, absorbed by 25.0 grams of water when the temperature of the water increases from 24.0 to 36.0?. forward reaction, which is endothermic. forward reaction, which is exothermic. reverse reaction, which is endothermic. reverse reaction, which is exothermic 56. ase your answer(s) to the following question(s) on the information below and on your knowledge of chemistry. Starting as a solid at 25, a sample of H 2 O is heated at a constant rate until the sample is at 125. This heating occurs at standard pressure. The graph below represents the relationship between temperature and heat added to the sample. 59. student dissolved a salt in water and noted that the temperature of the water decreased during the dissolving process. logical conclusion based on this observation is that the salt. dissolved exothermically. dissolved endothermically. ionized in water. oxidized in water 60. uring which phase change does 1 mole of carbon dioxide increase in entropy?. O 2 (g) O 2 (l). O 2 (l) O 2 (g). O 2 (g) O 2 (s). O 2 (l) O 2 (s) 61. t which temperature would the molecules in a one gram sample of water have the lowest average kinetic energy? Explain, in terms of heat of fusion and heat of vaporization, why the heat added during interval E is greater than the heat added during interval for this sample of water K. 100 K page 5

6 62. onsider the reaction: H 2 O(l) + energy H 2 (g) O 2(g) Which phrase best describes this reaction?. exothermic, releasing energy 68. Which graph shown could represent the uniform cooling of a substance, starting with the gaseous phase and ending with the solid phase?... exothermic, absorbing energy. endothermic, releasing energy. endothermic, absorbing energy The greatest amount of heat energy would be required to raise the temperature of a 1 gram sample of water from. 10 to to to to sample of water is cooled from 45 to 25 by the removal of 20 calories of heat. What is the mass of the water?. 10 g. 2.0 g. 20 g. 200 g 65. The graph shows the relationship between temperature and time as heat is added to one mole of a substance at a rate of 100 calories per minute. The substance is in the solid phase at Time = 0 minutes. 69. Which change of phase represents sublimation?. solid to liquid. solid to gas. liquid to gas. liquid to solid 70. t 1 atmosphere, which substance will sublime when heated?. O 2 (s). H 2 O(l). H 4 (g). Hl(aq) 71. ompared to a 1 mole sample of hydrogen at 273 K and 1 atmosphere, a 1 mole sample of hydrogen at 298 K and 1 atmosphere contains. more molecules. fewer molecules. molecules having higher average kinetic energy. molecules having lower average kinetic energy The temperature at which the substance begins to boil is Which change of phase is exothermic? 72. t STP, 44.8 liters of O 2 contains the same number of molecules as. 1.0 mole He moles of a Ne mole of H mole of N 2. gas to liquid. solid to liquid. solid to gas. liquid to gas kilogram sample of water will have the highest freezing point when it contains 73. Which sample is most likely to take the shape and total volume of its container?. O 2 (g). O 2 (l). O 2 (aq). O 2 (s) dissolved particles dissolved particles dissolved particles dissolved particles page 6

7 74. P (atm) V (ml) The table shows the changes in the volume of gas as the pressure changes at constant temperature. Which equation best expresses the relationship between pressure and volume for the gas? 75. Given the reaction at equilibrium: 2H 2 (g) + O 2 (g) 2H 2 O(g) + heat Which concentration changes occur when the temperature of the system is increased?. The [H 2 ] decreases and the [O 2 ] decreases.. The [H 2 ] decreases and the [O 2 ] increases... P = 500 atm ml V. PV = 500 atm ml V 1 = 500 atm ml. PV = atm ml P 500. The [H 2 ] increases and the [O 2 ] decreases.. The [H 2 ] increases and the [O 2 ] increases. 76. Which quantity contains a total of molecules of l 2 at STP?. 112 l g l g 77. Given the reaction: 4NH 3 (g) + 5O 2 (g) 4NO(g) + 6H 2 O(g) t STP, what is the total volume of O 2 (g) required to produce 80.0 liters of NO(g)? L L L. 100 L 78. What is the volume of 1.50 moles of an ideal gas at STP? L L L L 79. t constant pressure, which graph shows the correct relationship between the volume of a gas (V) and its absolute temperature (T)? 81. The behavior of a real gas would be most similar to the behavior of an ideal gas under conditions of. high pressure and high temperature. high pressure and low temperature. low pressure and high temperature. low pressure and low temperature Real gas behavior deviates from ideal gas behavior because the molecules of real gases. never collide... attract one another. are arranged in a regular geometric pattern. have no volume 80. t STP, the volume occupied by 32 grams of a gas is 11.2 liters. The gram molecular mass of this gas is closest to 83. Under the same conditions of temperature and pressure, which of the following gases would behave most like an ideal gas?. He(g). NH 3 (g). l 2 (g). O 2 (g). 8.0 g. 16 g. 32 g. 64 g page 7

8 84. When sugar is dissolved in water, the resulting solution is classified as a 87. solution in which an equilibrium exists between dissolved and undissolved solute must be. homogeneous mixture. heterogeneous mixture. homogeneous compound. heterogeneous compound. saturated. unsaturated. dilute. concentrated 88. s 1 gram of sodium hydroxide dissolves in 100 grams of water, the conductivity of the solution 85. In an aqueous solution of potassium chloride, the solute is. l. K. Kl. H 2 O 86. The following data were recorded while determining the solubility of a certain salt. Temp. ( ) Grams Solute/ 100 g H 2 O Which graph best represents the solubility of this salt?.. decreases. increases. remains the same 89. Which 0.1 M aqueous solution is the best conductor of electricity?. HF. HNO 2. H 2 SO 4. H 3 PO Which solution will freeze at the lowest temperature?. 1 mole of sugar in 500 g of water. 1 mole of sugar in 1,000 g of water. 2 moles of sugar in 500 g of water. 2 moles of sugar in 1,000 g of water. 91. Which of the following solutions, each containing a nonvolatile solute, will boil at the highest temperature?. 1 mole of electrolyte dissolved in 1000 g of H 2 O. 2 moles of electrolyte dissolved in 1000 g of H 2 O. 1 mole of nonelectrolyte dissolved in 1000 g of H 2 O. 2 moles of nonelectrolyte dissolved in 1000 g of H 2 O. 92. Which of the following gases is monatomic at STP?. hydrogen. chlorine. oxygen. helium. 93. Which substance is a conductor of electricity in the liquid phase but not in the solid phase?. r 2. Hr. Na. Nal 94. redox reaction always involves. a change in oxidation number. a change in phase. the transfer of protons. the formation of ions page 8

9 95. In the reaction l 2 + H 2 O HlO + Hl, the oxidation number of chlorine. decreases, only. increases, only. neither decreases nor increases. both decreases and increases 96. Which half-reaction correctly represents reduction?. S 2 + 2e S 0. S 2 S 0 + 2e. Mn e Mn 4+. Mn 7+ Mn e 97. Which occurs in the half-reaction Na(s) Na + + e?. Na(s) is reduced. Na(s) is oxidized. Na(s) gains electrons. Na + is oxidized 98. Which is a redox reaction?. ao 3 ao + O 2. NaOH + Hl Nal + H 2 O. 2NH 4 l + a(oh) 2 2NH 3 + 2H 2 O + al 2. 2H 2 O 2H 2 + O Which half-reaction correctly represents reduction?. Sn Sn 2+ 2e. Sn 2+ Sn e. Sn + 2e Sn 2+. Sn e Sn When the redox reaction shown is completely balanced using the smallest whole numbers, what is the coefficient of NO? g + HNO 3 gno 3 + NO + 2H 2 O 100. When the redox equation r 3+ (aq) + 3Mn(s) Mn 2+ (aq) + r(s) is completely balanced, the coefficient of r 3+ (aq) will be page 9

10 Problem-ttic format version c Educide Software Licensed for use by melanie campbell Terms of Use at 05/06/

11 Teacher s Key Page J The heat of vaporization of water is 2260 J/g and the heat of fusion for water is only 334 J/g. The heat of fusion of water is much less than its heat of vaporization

12 Teacher s Key Page

California Standards Test (CST) Practice

California Standards Test (CST) Practice 1. Which element has properties most like those of magnesium? (a) calcium (b) potassium (c) cesium (d) sodium 5. Which pair of atoms will share electrons when a