Chemistry 12. Chemistry 12 AUGUST 2005 AUGUST Course Code = CH. Course Code = CH. Student Instructions

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1 MINISTRY USE ONLY Place Personal Education Number (PEN) here. Chemistry 12 AUGUST 2005 Course Code = C Chemistry 12 AUGUST 2005 Course Code = C 1. Place the stickers with your Personal Education Number (PEN) in the allotted spaces above. Under no circumstance is your name or identification, other than your Personal Education Number, to appear on this booklet. 2. Ensure that in addition to this examination booklet, you have a Data Booklet and an Examination Response Form. Follow the directions on the front of the Response Form. 3. Disqualification from the examination will result if you bring books, paper, notes or unauthorized electronic devices into the examination room. Student Instructions 4. When instructed to open this booklet, check the numbering of the pages to ensure that they are numbered in sequence from page one to the last page, which is identified by END OF EXAMINATION. 5. At the end of the examination, place your Response Form inside the front cover of this booklet and return the booklet and your Response Form to the supervisor.

2 MINISTRY USE ONLY Question (.5) NR Question (.5) NR Place Personal Education Number (PEN) here. Question (.5) NR Question (.5) NR Chemistry 12 AUGUST 2005 Course Code = C Question (.5) NR Question (.5) NR Question (.5) NR Question (.5) NR Version

3 GENERAL INSTRUCTIONS 1. Aside from an approved calculator, electronic devices, including dictionaries and pagers, are not permitted in the examination room. 2. All multiplechoice answers must be entered on the Response Form using an B pencil. Multiplechoice answers entered in this examination booklet will not be marked. 3. For each of the writtenresponse questions, write your answer in the space provided in this booklet. 4. Ensure that you use language and content appropriate to the purpose and audience of this examination. Failure to comply may result in your paper being awarded a zero. 5. This examination is designed to be completed in two hours. Students may, however, take up to 30 minutes of additional time to finish.

4 CEMISTRY 12 PROVINCIAL EXAMINATION 1. This examination consists of two parts: Value Suggested Time PART A: 60 multiplechoice questions PART B: 8 writtenresponse questions Total: 90 marks 120 minutes 2. The following tables can be found in the separate Data Booklet: Periodic Table of the Elements Atomic Masses of the Elements Names, Formulae, and Charges of Some Common Ions Solubility of Common Compounds in Water Solubility Product Constants at 25 C Relative Strengths of BrønstedLowry Acids and Bases AcidBase Indicators Standard Reduction Potentials of alfcells No other reference materials or tables are allowed. 3. A calculator is essential for the Chemistry 12 Provincial Examination. The calculator must be a handheld device designed primarily for mathematical computations involving logarithmic and trigonometric functions and may be capable of performing graphing functions. Computers, calculators with a QWERTY keyboard or symbolic manipulation abilities, and electronic writing pads will not be allowed. Students must not bring any external devices (peripherals) to support calculators such as manuals, printed or electronic cards, printers, memory expansion chips or cards, CDROMs, libraries or external keyboards. Students may have more than one calculator available during the examination, of which one may be a scientific calculator. Calculators may not be shared and must not have the ability to either transmit or receive electronic signals. In addition to an approved calculator, students will be allowed to use rulers, compasses, and protractors during the examination. Calculators must not have any information programmed into memory that would not be acceptable in paper form. Specifically, calculators must not have any builtin notes, definitions, or libraries. There is no requirement to clear memories at the beginning of the examination but the use of calculators with builtin notes is equivalent to the use of notes in paper form. Any student deemed to have cheated on a provincial examination will receive a 0 on that examination and will be permanently disqualified from the Provincial Examination Scholarship Program.

5 PART A: MULTIPLE COICE Value: 60 marks INSTRUCTIONS: Suggested Time: 80 minutes For each question, select the best answer and record your choice on the Response Form provided. Using an B pencil, completely fill in the circle that has the letter corresponding to your answer. 1. Which of the following could not be units for reaction rate? A. sec 1 B. gml C. M min D. C hour 2. Which of the following represents the typical mathematical relationship between reaction rate and time? A. B. Rate Rate Time Time C. D. Rate Rate Time Time 2005 Province of British Columbia. All rights reserved. Page 1

6 3. Consider the following reaction: Zn( s) + 2Cl( aq) Æ ZnCl2( aq) + 2( g) In two different experiments, equal moles of Zn and equal volumes of Cl are reacted. After 2 minutes, the volume of 2 produced is recorded as follows: Zn Temp [ Cl] Volume 2 ml ( ) Experiment 1 strip 10 C M Experiment 2 powdered 15 C 30. M 73. Which of the following factors explains why the rate in Experiment 1 is different than the rate in Experiment 2? A. [ Cl] B. temperature C. nature of reactants D. surface area of Zn Page Province of British Columbia. All rights reserved.

7 2005 Province of British Columbia. All rights reserved. Page 3 4. Consider the following reaction: Br C + O Æ Br + O C Which of the following could be true of the activated complex? Structure PE (relative to reactants) A. Br C O È Î 2 lower B. Br C O È Î lower C. Br C O È Î 2 higher D. Br C O È Î higher

8 5. Consider the following PE diagram: 600 PE (kj) Progress of the reaction Which of the following is true for the forward reaction? D Ea ( kj) A B C D Which of the following would have a positive value for D? I. the evaporation of water II. the burning of a match III. the explosive reaction between 2 and O 2 IV. a chemical cold pack A. III only B. IV only C. I and IV D. II and III Page Province of British Columbia. All rights reserved.

9 7. Which of the following represents the value for the activation energy of the forward reaction in an equilibrium system? A. E = E + ( D) a( forward) a( reverse) B. E = E ( D) a( forward) a( reverse) C. E = ( D) E a( forward) a( reverse) D. E = ( D) E a( forward) a( reverse) 8. Consider the following equilibrium: CaCO3( s) Æ CaO( s) + CO2( g) In which of the flasks will this equilibrium be established? Flask 1 Flask 2 Flask 3 Flask 4 CO 2 (g) CO 2 (g) CaCO 3 (s) CaO(s) CaCO 3 (s) CaO(s) A. 1, 2, 3 only B. 1, 2, 4 only C. 1, 3, 4 only D. 3, 4 only 9. Which of the following forward reactions demonstrates decreasing enthalpy and increasing entropy?? 1 A. g( l) + O ( g) Æ go( s) D = kj ? B. 2Cl( g) Æ ( g) + Cl ( g) D = + 185kJ 2 2? C. 2gO( s) Æ 2g( l) + O ( g) D = + 182kJ? D. 2SO ( g) Æ 2SO ( g) + O ( g) D = 200 kj Province of British Columbia. All rights reserved. Page 5

10 Use the following equilibrium system to answer questions 10 to 12. 4N ( g) + 3O ( g) Æ 2N ( g) + 6 O( l) D = 1530kJ Which of the following would cause the amount of N 3 at equilibrium to increase? A. an increase in [ O 2 ] B. a decrease in volume C. a decrease in temperature D. an increase in temperature 11. What happens when O 2 is added to the above system? Equilibrium [ N 2 ] A. no shift unchanged B. shifts right decreases C. shifts right increases D. shifts left increases 12. If some O 2 is injected into the system, what happens to the forward and reverse reaction rates during the shift to reestablish equilibrium? Forward Reaction Rate Reverse Reaction Rate A. increases decreases B. decreases decreases C. increases increases D. decreases increases Page Province of British Columbia. All rights reserved.

11 13. Consider the equilibrium expression K eq1 for reaction 1: 1 SO ( g) + O ( g) Æ SO ( g) and the equilibrium expression K eq2 for reaction 2: 2SO ( g) Æ O ( g) + 2SO ( g) ow is K eq2 related to K eq1? A. K = K eq2 eq1 = ( ) 2 B. K K eq2 eq C. K D. K eq2 eq2 = Ê Ë Á 1 ˆ K eq1 = Ê Ë Á 1 ˆ K eq Which of the following describes how a K eq value is related to the relative concentrations of reactants and products? K eq value Relative Concentration I. large [ products] > [ reactants] II. large [ reactants] > [ products] III. small [ products] > [ reactants] IV. small [ reactants] > [ products] A. I only B. IV only C. I and IV only D. II and III only 2005 Province of British Columbia. All rights reserved. Page 7

12 15. Consider the following equilibrium system: N2( g) + O2( g) Æ 2NO( g) Under certain conditions, K eq = When conditions are changed, Keq becomes Which of the following could account for this? A. [ N 2 ] was changed. B. A catalyst was added. C. Pressure was changed. D. Temperature was changed. 16. Consider the following equilibrium system: 2Sg ( ) Æ 2 ( g) + S ( g) At equilibrium, a 20. L reaction vessel contained mol 2S, mol 2 and mol S 2. What is the value of K eq? A B C D Consider the following equilibrium equation: CaCO3( s) Æ CaO( s) + CO2( g) Keq = 010. Initially, g CaCO 3 were placed in a 20. L container. What mass of CO 2 will be present at equilibrium? A g CO2 B. 88. gco2 C. 15gCO2 D. 22. g CO2 Page Province of British Columbia. All rights reserved.

13 18. The solubility of a solute is best determined from which type of solution? A. a saturated solution B. any solution at 25 C C. an unsaturated solution D. a supersaturated solution 19. What will be the [ Cl ] when equal volumes of 010. M NaCl and 020. M AlCl 3 are combined? A M B M C M D M 20. Which equation represents the reaction between 0. 2MNa2CO 3 and 0. 2M Ba( NO3 ) 2? A. Na ( aq) + NO ( aq) Æ NaNO ( s) B. Ba ( aq) + CO ( aq) Æ BaCO ( s) C. Na CO ( s) Æ Na ( aq) + CO ( aq) D. Ba( NO ) ( aq) + Na CO ( aq) Æ BaCO ( aq) + 2NaNO ( s) Which of the following solutions could be used to separate the anions SO 4 2 and CO 3 2 from each other by precipitation? A. NaNO3 ( aq) B. AgNO3 ( aq) C. Fe( NO3 ) 3 ( aq) D. Ba( NO3 ) 2 ( aq) 2005 Province of British Columbia. All rights reserved. Page 9

14 22. Which pair of ions would be suitable for removing the cations responsible for hard water? A. + and Cl B. NO 3 and I C. S 2 2 and SO 4 2 D. CO 3 3 and PO What is the K sp expression for Zn( O) 2? sp = [ ][ ] sp = [ ] [ ] sp = 2 [ + ][ 2 2 ] sp = [ + ] + [ ] A. K Zn O B. K Zn O C. K Zn O 2 2 D. K Zn 2 O 24. Which compound will have the lowest solubility? A. BeS B. FeS C. ZnS D. Cs 2 S 25. A solution is found to have an initial Pb 2 + What will be observed as the ions interact? [ ] of M and a Br [ ] of M. Observation Reason A. precipitate Trial K > K B. precipitate Trial K < K C. no precipitate Trial K > K D. no precipitate Trial K < K sp sp sp sp sp sp sp sp Page Province of British Columbia. All rights reserved.

15 26. Which relationship can be used to calculate the maximum Ba 2 + solution of Na 3PO4? 2 + Ksp A. [ Ba ] = 3 [ PO4 ] B. Ba C. Ba 2 + [ ] = 2 + [ ] = K PO 3 2 sp 3 [ 4 ] K PO sp 3 [ 4 ] [ ] = [ ] sp 4 D. Ba K PO [ ] that can exist in a 27. What is produced when C3N2 acts as a base in water? A. C3N + B. C3N3 + C. C3N2 D. C2N2 28. What species will form when + ions are in the presence of O 2 molecules? A. O + B. + O 2 + C. O 3 + D. O What is the conjugate acid of the base AsO 4 2? A. AsO B. 2AsO4 C. 2AsO4 D. AsO Province of British Columbia. All rights reserved. Page 11

16 30. Which solution will have the greatest electrical conductivity? A M Cl B M RbO C M K3PO4 D. 20. M C612O6 31. The following equilibrium favours the formation of products: N O + C N Æ C N + N O Which species is the strongest acid? + A. N3O B. N O 2 C. C3N2 + D. C3N3 32. Which of the following solutions would have the greatest [ O ]? A. 01. M CO 3 B M PO 4 C. 01. M 2PO 4 D. 01. M 2BO Given that the ionization of water is endothermic, which of the following is true if temperature is decreased? K w Reason A. decreases equilibrium shifts left B. decreases equilibrium shifts right C. increases equilibrium shifts left D. increases equilibrium shifts right Page Province of British Columbia. All rights reserved.

17 34. Which of the following would be a typical p of soda pop? A. 10. B. 32. C. 68. D What is the [ KO] in a KO solution that has a p = ? A M B M C. 20. M D M What is the [ O 3 ] in 070. M CN? A M B M C M D M 37. The S 2 ion is a relatively strong base with an equilibrium constant of What is the K a value for S? A B C D Province of British Columbia. All rights reserved. Page 13

18 38. Which of the following is true as a result of the predominant hydrolysis of NaCO 3? Solution Reason A. basic K > K B. basic K > K C. acidic K > K D. acidic K > K a b a b b a b a 39. A salt forms in the reaction between F( aq) and NaO( aq). What is the net ionic equation for the hydrolysis of this salt? + A. NaF( aq) Æ Na ( aq) + F ( aq) + B. F( aq) + O( l) Æ O ( aq) + F ( aq) 2 3 C. F ( aq) + O( ) Æ F( aq) + O ( aq) 2 l D. F( aq) + NaO( aq) Æ NaF( aq) + 2O( l) 40. What is the K a for the indicator that is yellow in its basic form and blue in its acid form? A B C D What term is used to describe the point at which a chemical indicator changes colour? A. titration point B. transition point C. equivalence point D. stoichiometric point Page Province of British Columbia. All rights reserved.

19 42. When ml samples of the strong acid SO following results were obtained: 2 4 were titrated with 025. M NaO the Titration Volume of NaO( aq) ml ml mL What is the concentration of the SO 2 4 sample? A M B M C M D M 43. Which of the following equations describes the predominant reaction that occurs at the equivalence point of a titration between C3 COO( aq) and NaO( aq)? + A. ( aq) + O ( aq) Æ O( ) 2 l B. C COO ( aq) + O( l) Æ C COO( aq) + O ( aq) C. C3COO( aq) + NaO( aq) Æ NaC3COO( aq) + 2O( l) D. ( aq) + CCOO ( aq) + Na ( aq) + O ( aq) Æ Na ( aq) + C COO ( aq) + O( ) l 2005 Province of British Columbia. All rights reserved. Page 15

20 Use the following equilibrium equation and data to answer questions 44 and CN( aq) + O( l) Æ O ( aq) + CN ( aq) M M M 44. Why is the solution above not considered to be a true buffer solution? A. excessive [ CN] B. + excessive O 3 [ ] [ ] C. insufficient CN D. insufficient [ CN] 45. What could be added to 1. 0L of this solution in order for it to behave as a true buffer? A. 10. mol Cl B. 10. mol CN C. 10. mol 3O + D. 10. mol NaCN 46. Which of the following equations correctly represents the reaction of a metallic oxide with water? A. KO 2 + O 2 Æ 2KO B. SO3 + 2O Æ2SO4 C. Na2O + 2O Æ Na2O2 + 2 D. NaO + O Æ Na + 2 O 2 2 Page Province of British Columbia. All rights reserved.

21 47. Identify the substance that is oxidized in the following equation: A. Br 2 B. SO 2 C. O 2 D. Na2SO4 Br + SO + Na SO + 2 O Æ 2 SO + 2NaBr What is the reducing agent in the following equation? Fe + 2I Æ 2Fe + I 2 A. I 2 B. I C. Fe 2 + D. Fe What is the oxidation number of C in the CO ion? A. 1 3 B. 2 3 C. 1 D A solution of Ag( NO 3 ) 2 (an unusual form of silver) reacts with gold metal while a solution of AgNO 3 does not react with gold. What is the order of oxidizing agents when arranged from strongest to weakest? A. Ag, Au, Ag B. Au, Ag, Ag C. Ag, Au, Ag D. Ag, Ag, Au Province of British Columbia. All rights reserved. Page 17

22 51. Which of the following best describes what happens when lead solid is placed in a 1. 0M solution of Cu( NO 3 ) 2? A. Bubbles form on the lead. B. No changes are observed. C. Copper solid forms on the lead and the solution changes colour. D. The mass of lead solid increases and the solution does not change colour. 52. Consider the following redox reaction: 2KClO + 2 C O Æ 2ClO + 2CO + K C O + 2 O What is the oxidation halfreaction? A. 2e + C O Æ 2 + 2CO B. CO Æ 2 + 2CO + 2e + C. 2 + ClO3 Æ ClO2 + 2O + e D. e + + ClO Æ ClO + O 53. A g sample of impure NaI is analyzed by titration with M CuSO 4 solution according to the following equation: 2 + 4I + 2Cu Æ 2CuI + I 2 ow many moles of NaI are present in the sample if the titration requires ml of CuSO 4 solution? A mol B mol C mol D mol Page Province of British Columbia. All rights reserved.

23 Use the following cell diagram for questions 54 to 56. electrons Volts inert electrode 1.0 M KNO3 Cd 1.0 M g(no 3 ) M Cd(NO3 )2 g(l) 54. Which of the following is the correct anode halfcell reaction? 2 + A. Cd + 2e Æ Cd 2 + B. g + 2e Æ g 2 + C. g Æ g + 2e 2 + D. Cd Æ Cd + 2e 55. Which of the following describes the change in mass of the g( l) and the movement of nitrate ions? Mass of g( l) Nitrate Ions A. increases towards the Cd electrode B. decreases towards the Cd electrode C. increases towards the inert electrode D. decreases towards the inert electrode 56. If the standard cell voltage is 125. V, what is the reduction halfcell potential for Cd? A V B V C V D V 2005 Province of British Columbia. All rights reserved. Page 19

24 57. Consider the following electrochemical cell: 2 (g) Pt (inert) Porous Barrier Cu 1.0 M Cl 1.0 M CuSO 4 Which of the following could be used to confirm the ion migration through the porous barrier? A. adding phenolphthalein to the copper halfcell B. adding phenolphthalein to the hydrogen halfcell C. adding barium nitrate solution to the copper halfcell D. adding barium nitrate solution to the hydrogen halfcell 58. Which of the following is an example of corrosion? A. copper spontaneously oxidizing B. sulphur spontaneously oxidizing C. copper nonspontaneously oxidizing D. sulphur nonspontaneously oxidizing Page Province of British Columbia. All rights reserved.

25 59. A student brought an old silver medal to the Chemistry Lab to plate it with copper. e set up a cell like the one in the following diagram: Object 1 Object 2 Medal 1.0 M CuSO 4 Which of the following combinations should produce the best result? Object 1 Electron Flow Object 2 A. AC power supply towards the medal Ag B. DC power supply towards the medal copper C. DC power supply from the medal copper D. voltmeter from the medal Pt 60. Which of the following occurs when a solution of NiSO 4 is electrolyzed using inert carbon electrodes? A. The cathode dissolves. B. ydrogen gas is produced. C. The p of the solution decreases. D. The Ni 2 + concentration increases. This is the end of the multiplechoice section. Answer the remaining questions directly in this examination booklet Province of British Columbia. All rights reserved. Page 21

26 PART B: WRITTEN RESPONSE Value: 30 marks INSTRUCTIONS: Suggested Time: 40 minutes You are expected to communicate your knowledge and understanding of chemical principles in a clear and logical manner. Your steps and assumptions leading to a solution must be written in the spaces below the questions. Answers must include units where appropriate and be given to the correct number of significant figures. For questions involving calculations, full marks will NOT be given for providing only an answer. 1. Consider the following reaction mechanism: Step 1 Cl2 Æ 2Cl (fast) Step 2 Cl + CO Æ COCl (slow) Step 3 COCl + Cl2 Æ COCl2 + Cl (fast) Identify a reaction intermediate in the reaction mechanism and write the equation for the overall reaction. Explain why increasing the CO but increasing the Cl 2 Reaction Intermediate: Overall Reaction Equation: Explanation: [ ] will increase the reaction rate, [ ] will not. (5 marks) Page Province of British Columbia. All rights reserved.

27 2. Consider the following equilibrium: CO( g) + O( g) Æ CO ( g) + ( g) K = eq 46. Initially, 050. mol CO, 050. mol 2O, 0. 62mol CO 2 and 0. 62mol 2 are placed in a 10. L container, and the reaction proceeds towards products. Calculate the equilibrium [ 2 ]. (3 marks) 3. A solution is prepared by mixing equal moles of Ba( NO 3 ) 2, K2SO4 and BaS and precipitation occurs. Identify the precipitate(s) and write the net ionic equation(s) for the reaction(s). (3 marks) Precipitate(s): Net Ionic Equation(s): 2005 Province of British Columbia. All rights reserved. Page 23

28 4. Write balanced equations to show water acting as an acid with C3C2N2, then water acting as a base with 2 O 2. (4 marks) As an acid: As a base: 5. Calculate the initial concentration of a solution of N 3 which has a p = and Kb = Begin by writing the equation for the predominant reaction. (5 marks) Page Province of British Columbia. All rights reserved.

29 6. A sample of the strong acid Cl( aq) is titrated with a sample of N3 ( aq), a weak base. Write the formula, complete ionic and net ionic equations for the titration reaction. (3 marks) 7. In an unusual compound, IPO 4, iodine exists as Iodine(III). The compound decomposes as follows: 3 IPO Æ I + IO + PO ( acidic) Balance this redox equation in acidic solution. (4 marks) 2005 Province of British Columbia. All rights reserved. Page 25

30 8. In separate electrolysis experiments, 10. M NaCl, 10. M KNO 3, 10. M Li2SO 4, and 10. M Cs3PO 4 all produced the same gas at their cathodes. Write the equation for the formation of this gas and explain why this same reaction occurs in all four cases. (3 marks) END OF EXAMINATION Page Province of British Columbia. All rights reserved.

PROVINCIAL EXAMINATION MINISTRY OF EDUCATION CHEMISTRY 12 GENERAL INSTRUCTIONS

INSERT STUDENT I.D. NUMBER (PEN) STICKER IN THIS SPACE JUNE 1998 PROVINCIAL EXAMINATION MINISTRY OF EDUCATION CHEMISTRY 12 GENERAL INSTRUCTIONS 1. Insert the stickers with your Student I.D. Number (PEN)