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Review for Benchmark #2

Review for Benchmark #2. Indicate the equilibrium expressions for the following reaction: 3Y 2 (g) + X 2 (g) <-> 2XY 3 (g). 10. [XY3] 2 / [X2][Y2] 3 [XY3]/[X2][Y2] 2[XY3]/[X2]3[Y2] [X2][Y2] 3 /[XY3] 2 [X2][Y2]/[XY3].

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Review for Benchmark #2

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  1. Review for Benchmark #2

  2. Indicate the equilibrium expressions for the following reaction: 3Y2(g) + X2(g) <-> 2XY3(g) 10 • [XY3]2 / [X2][Y2]3 • [XY3]/[X2][Y2] • 2[XY3]/[X2]3[Y2] • [X2][Y2]3/[XY3]2 • [X2][Y2]/[XY3]

  3. If the formation of ammonia, shown below, is exothermic at 25oC, what will be the effect of increasing the temperature of the system? 3H2(g) + N2(g) <-> 2 NH3(g) 10 • The equilibrium will shift to the right • The value of K will increase • The [H2] will decrease • The value of K will decrease • Equilibrium is dependent on the initial concentrations and equation stoichiometry, not on temperature. There will be no change

  4. The image shows a titration of a: 10 • Strong acid with a strong base • Strong acid with a weak base • Weak acid with a strong acid • Weak acid with a strong base • Weak base with a strong acid

  5. Catalysts lower the activation energy by: 10 • Providing an alternative pathway for the reaction • Increasing the energy content of the reactants • Changing the value of ΔH for the reaction • Adding heat to the reaction system • None of these

  6. The rate law for a reaction is determined to be rate = k[A]2[B]2. What is the overall order for the reaction? 10 • Zero • Third • Second • First • Fourth

  7. KClO3 decomposes according to the following reaction: 2KClO3 2KCl + 3O2. If the rate of decomposition of KClO3 at a certain time is determined to be 2.4 x 10-2 mol s-1, what is the rate of formation of O2 at the same time? 10 • 1.6 x 10-2 mol/s • 2.4 x 10-2 mol/s • 3.6 x 10-2 mol/s • 1.2 x 10-2 mol/s • 7.2 x 10-2 mol/s

  8. For the reaction between X and Y the data shown on the table was obtained. What is the rate law for the reaction? 10 • Rate = k[Y]2 • Rate = k[X][Y] • Rate = k[X]2[Y] • Rate = k[X][Y]2 • Rate = k[X]2[Y]2

  9. A certain first order reaction is 50% complete in 4.26 minutes. What is the rate constant for the reaction? 10 • 0.163 min-1 • 0.0252 min-1 • 6.13 min-1 • 2.95 min-1 • [A]o/2t1/2

  10. For the following reaction, A  B + C that is second order, a linear plot will result when time is plotted against: 10 • ln[B] • ln[A] • ln[B][C] • 1/[A] • [A]

  11. Which of the following statements is true for the catalyzed and uncatalyzed versions of the same reaction? 10 • The activation energies are the same • The energy content of the activated complex is higher for the catalyzed reaction • The reaction pathway is the same • The energy content of the reactants is higher for the uncatalyzed reaction • ΔHis the same

  12. The activation energy for the reaction: X2(g) + Y2(g)  2XY(g) is 125 kJ/mol and ΔH for the reaction is -45 kJ/mol. The activation energy for the decomposition of XY is: 10 • 80 kJ/mol • 170 kJ/mol • 45 kJ/mol • -80 kJ/mol • -125 kJ/mol

  13. Increasing the temperature at which a reaction occurs speeds up the reaction by: 10 • Activating catalysts • Two of these • Increasing the energy of collisions • Improving the orientation of collisions • Increasing the frequency of collisions

  14. For a first order reaction with a rate constant k = 1.2 x 10-3 s-1, how long will it take for the amount of reactant to be decreased from 0.10 mol to 0.05 mol? 10 • 6.7 s • 580 s • 8.3 x102 s • 8.3 x 103 s • None of these

  15. A certain first order decomposition reaction reaches 65% completion in 18.9 s. What is the rate constant for this reaction? 10 • 18 s-1 • 5.55 x 10-2 s-1 • 2.38 x10-2 s-1 • 9.56 x 10-2 s-1 • 19.8 s-1

  16. Consider the following equilibrium:X2(g) + Y2(g) <-> 2XY(g) + energyAddition of XY(g) will: 10 • Cause [X2] to increase • Drive the reaction to the right • Cause the energy of the system to increase • Cause [Y2] to decrease • Two of these to occur

  17. The hydrogen halides are all polar molecules which form acidic solutions. Which of the following is the weakest acid? 10 • HF • HCl • HBr • HI

  18. A chemist desires to create a buffer solution beginning with 1.00 liter of 0.200 M NH3. How many moles of gaseous HCl must be introduced in order to produce a buffer of maximum capacity? 10 • 0.200 mol HCl • 0.100 mol HCl • 0.500 mol HCl • 0.300 mol HCl • None- the solution is already buffered

  19. The Ksp of BaSO4 is 1.5 x 10-9. How many grams of BaSO4 can be dissolved in 1000 liters of solution? 10 • 0.085 g • 170 g • 9.1 g • 2.3 g • 39 g

  20. Calculate the pH of a 0.00175 M solution of KOH. 10 • -2.76 • 7.89 • 2.76 • 11.2 • 12.7

  21. Imagine a 1.0 L container in which 2.0 mol samples of gaseous substances A, B, and C are introduced. A and B react according to the following equation: A(g) + B(g) <-> 2C(g). If the value of K=4.2, in what direction does the equilibrium exist? 10 • Far to the right • Slightly to the right • Far to the left • Slightly to the left • The reaction is at equilibrium

  22. Imagine a 1.0 L container into which 2.0 mol samples of gaseous substances A, B, and C are introduced. A and B react according to the following equation: A(g) + B(g) <-> 2C(g). If K=2.68 for this reaction, what is the equilibrium concentration of C? 10 • 2.02 M • 1.3 M • 2.7 M • 0.7 M • None of these

  23. For the reaction forming ammonia, 3H2(g) + N2(g) <->2NH3(g), what effect will increasing the pressure by decreasing the volume of the system have on this system at equilibrium? 10 • It will favor the formation of more ammonia • It will shift the equilibrium to the left • The [H2] will increase • The [N2] will increase • It will have no effect on the equilibrium concentrations.

  24. Calculate Ksp of Ba(OH)2 given the fact that the solubility of Ba(OH)2 in water is 4.6 g per 0.250 liter. 10 • 4.9 x 10-3 • 1.2 x 10-2 • 1.1 x 10-1 • 1.5 x 10-4 • 2.0 x 10-7

  25. A buffer solution is prepared that is 0.50 M in propanoic acid and 0.40 M in sodium propanoate with a solution volume of 1.00 L. (Ka for propanoic acid = 1.3 x 10-5. What is the pH of the solution when 0.60 mol of NaOH (s) is added to the solution? Assume no change in solution volume. 10 • 3.97 • 4.97 • 4.77 • 4.67 • 4.91

  26. 200.0 mL of 0.200 M HCl is titrated with 0.050 M NaOH. What is the pH after the addition of 100 mL of the NaOH solution? 10 • 1.45 • 0.76 • 0.93 • 1.03 • 0.82

  27. You are given a box containing NH3, H2, and N2 at equilibrium at 1000oC. Analysis of the contents shows the concentrations as follow: [NH3] = 0.102 M, [H2] = 1.62 M, and [N2] = 1.03 M. Calculate K for the reaction: 2NH3(g) <-> N2(g) + 3H2(g) 10 • 2.37 x 10-3 • 4.21 x 102 • 3.89 x 10-4 • 3.89 x 104 • 9.02 x 10-6

  28. Imagine a 1.0 L container into which 2.0 mol samples of gaseous substances A, B, and C are introduced. A and B react according to the following equation: A(g) + B(g) <-> 2C(g). An increase in temperature of the system would: 10 • Drive the reaction to the right • Drive the reaction to the left • Have no effect on the reaction • The effect cannot be determined

  29. Which of the following is always true for a reaction whose value for K is 4.4 x 104? 10 • The reaction proceeds far to the right • The reaction proceeds far to the left • The reaction occurs quickly • The reaction occurs slowly • Two of these

  30. If an acid, HA, is 15% dissociated in a 2.00 M solution, what is the Ka for the acid? 10 • 7.5 x 10-2 • 1.2 x 10-2 • 1.1 x 10-2 • 5.3 x 10-2 • 6.4 x 10-3

  31. Suppose that 0.250 L of a buffer solution contains 0.225 M acetic acid and 0.225 M soldium acetate. What would be the pH change if 30.0 mL of 0.100 M HCl is added to this buffer? Assume the volumes are additive. Ka for acetic acid is 1.8 x 10-5. 10 • 4.70 to 4.78 • 4.74 to 4.70 • 4.74 to 4.82 • 5.40 to 7.68 • 6.40 to 4.56

  32. At 25oC a solution has a [OH-] = 2.90 x 10-2. Calculate the pH of the solution. 10 • 12.5 • 1.54 • -4.54 • 9.03 • 3.17

  33. What is the pH of a buffer solution consisting of 0.150 mol of NH3 plus 0.250 mol of NH4Cl in enough water to make 0.750 liter of solution? Kb = 1.81.x 10-5. 10 • 9.038 • 4.963 • 2.721 • 11.279 • 8.547

  34. 50.0 mL of 0.100 M NH3 Is titrated with 0.025 M HCl. What is the pH of the solution after 100 mL of HCl has been added? Kb for NH3 = 1.81 x 10-5 10 • 4.74 • 12.45 • 10.90 • 8.99 • 9.26

  35. What is the pH of a 0.00350 M HNO3 solution? 10 • -2.46 • 2.46 • 1.01 • 6.78 • 4.90

  36. What is the correct unit for the rate constant for a reaction that is first order overall? 10 • L/mol s • Mol/L s • Mol2/L2 s • L2/Mol2 s • s-1

  37. The most common types of radioactive decay, in order from most penetrating to least penetrating, is 10 • alpha, beta, gamma • beta, gamma, alpha • gamma, alpha, beta • gamma, beta, alpha

  38. Phophorus-15 has a half life of 14 days. What fraction of the original phosphorus-15 remains after 8 weeks? 10 • ¼ • 1/8 • 1/32 • ½ • 1/16

  39. What isotope forms as potassium-37 undergoes positron emission? 10 • Argon-37 • Argon-38 • Argon-36 • Calcium-37 • Calcium-38

  40. Which of the following statements is true? 10 • All man-made isotopes are radioactive. • Some man-made isotopes are radioactive • None of the man-made isotopes are radioactive.

  41. The nuclide radium-226 is the daughter nuclide resulting from the alpha decay of what parent nuclide? 10 • Radium-225 • Polonium-214 • Thorium-230 • Radon-222 • Thorium-228

  42. An electron emitted from the nucleus during some kinds of radioactive decay is known as 10 • A beta particle • An alpha particle • A gamma ray • A positron

  43. Carbon-12 and carbon-13 are stable isotopes of the element. Which of the following isotopes is most likely to undergo positron emission? 10 • Carbon-11 • Carbon-14 • Carbon-12 • Carbon-13 • Carbon-15

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