Chemistry 12. Examination Booklet 2007/08 Released Exam August 2008 Form A DO NOT OPEN ANY EXAMINATION MATERIALS UNTIL INSTRUCTED TO DO SO.

Transcription

1 Chemistry 12 Examination Booklet 2007/08 Released Exam August 2008 Form A DO NOT OPEN ANY EXAMINATION MATERIALS UNTIL INSTRUCTED TO DO SO FOR FURTHER INSTRUCTIONS REFER TO THE RESPONSE BOOKLET Contents: 19 pages Examination: 2 hours 50 multiple-choice questions Additional Time Permitted: 60 minutes Province of British Columbia

2

3 PART A: MULTIPLE CHOICE Value: 625% of the examination Suggested Time: 80 minutes INSTRUCTIONS: For each question, select the best answer and record your choice on the Answer Sheet provided Using an HB pencil, completely fill in the bubble that has the letter corresponding to your answer You have Examination Booklet Form A In the box above #1 on your Answer Sheet, fill in the bubble as follows Exam Booklet Form/ Cahier d examen A B C D E F G H 1 Consider the reaction: H 2 ( g) + I 2 ( g) 2HI( g) Which of the following would decrease the rate of reaction? [ ] A an increase in I 2 B a decrease in [ HI] C a decrease in [ H 2 ] D an increase in temperature 2 Consider the reaction: ZnS( s) + H 2 SO 4 ( aq) O ( 2 g) ZnSO 4 ( aq) + Ss ( ) + H 2 O( ) What would increase the fraction of successful collisions? I increasing temperature II increasing surface area of ZnS III increasing [ H 2 SO 4 ] IV adding a suitable catalyst A I and II only B I and IV only C II and III only D I, II, III and IV Chemistry Form A Page 1

4 3 Consider the following two reactions occurring under the same conditions: I II C 2 H 5 Cl() C 2 H 4 ()+ g HCl() g E a = 254 kj C 2 H 5 Br() C 2 H 4 ()+ g HBr() g E a = 219 kj Which of the following is correct? A Reaction I is faster because it has a higher E a B Reaction II is faster because it has a lower E a C Reaction I is slower because it is exothermic D Reaction II is slower because it is endothermic 4 An uncatalyzed reaction has the following values for E a : E a ( forward ) = 250 kj E a ( reverse ) = 100 kj If a catalyst is added to the reaction, which of the following values could be correct? E a ( forward ) ( kj) E a ( reverse) ( kj) H ( forward ) ( kj) A B C D Page 2 Chemistry Form A

5 5 Consider the following reaction mechanism: Step 1: C 2 H 5 HgI C 2 H 5 Hg + + I Step 2: C 2 H 5 Hg + + Cl Particle 1 Overall C 2 H 5 HgI + Cl C 2 H 5 HgCl + I Identify Particle 1 and a reaction intermediate from the above mechanism Particle 1 Reaction Intermediate A C 2 H 5 Hg + C 2 H 5 HgI B C 2 H 5 HgI C 2 H 5 Hg + C C 2 H 5 HgCl I D C 2 H 5 HgCl C 2 H 5 Hg + 6 Consider the following PE diagram for a reversible reaction: 500 PE (kj) Progress of the reaction Which of the following correctly corresponds to the diagram above? PE of activated complex (kj) E a ( reverse ) (kj) H ( forward ) ( kj) A B C D Chemistry Form A Page 3

6 7 Reacting systems naturally tend toward what changes in enthalpy and entropy? Change in Enthalpy Change in Entropy A decreasing increasing B decreasing decreasing C increasing increasing D increasing decreasing Page 4 Chemistry Form A

7 Use the following equilibrium to answer questions 8 to 10 NH 4 Cl( s) NH 3 ( g) + HCl ( g) H = +176 kj 8 Which of the following would cause a shift to the right? A adding NH 4 Cl B removing NH 3 C increasing pressure D decreasing temperature 9 When HCl is added, how do the concentrations of NH 3 and HCl at the new equilibrium compare to the original equilibrium concentrations? [ NH 3 ] [ HCl] A higher higher B higher lower C lower higher D lower lower 10 Solid NH 4 Cl is added to the preceding equilibrium What will happen to the forward and reverse rates? Forward Rate Reverse Rate A increases increases B no change no change C increases decreases D decreases increases Chemistry Form A Page 5

8 11 Due to a change in temperature, a system at equilibrium shifts, causing the concentration of products to change Which of the following could be correct? [Products] Value of K eq A I only B II only C I and IV only D II and III only I increases no change II increases increases III decreases decreases IV decreases increases 12 Consider the following equilibrium: Cs ( ) + H 2 Og ( ) CO( g) + H 2 ( g) K eq = 016 At equilibrium, there are 060 mol C, 030 mol H 2 O and 032 mol CO in a 10 L flask What is the equilibrium [ H 2 ]? A 0090 M B 015 M C 35 M D 59M 13 Consider the equilibrium: 2SO 2 ( g) + O 2 ( g) 2SO 3 ( g) Initially, 16 mol SO 3 is placed in a 30 L container At equilibrium, [ O 2 ] = 015 M What is the value of K eq? A 026 B 12 C 40 D 43 Page 6 Chemistry Form A

9 14 Consider the following equilibrium system: 2CH 4 ( g) C 2 H 2 ( g) + 3H 2 ( g) K eq = 28 Initially, 04 mol of each substance is placed in a 10 L container Which of the following correctly describes this system as it approaches equilibrium? [ C 2 H 2 ] Forward Rate A increases decreases B increases increases C decreases decreases D decreases increases 15 Which solution will have the greatest electrical conductivity? A 010 M HCl B 10 M LiOH C 20 M H 3 PO 4 D 20 M CH 3 CH 2 OH 16 What are the ion concentrations that result when mol of K 3 PO 4 is dissolved to produce L of solution? K + 3 PO 4 A M M B M M C M M D M M Chemistry Form A Page 7

10 17 What happens when equal volumes of 02M Na 2 SO 3 and 02M CaS are mixed? A Only Na 2 S precipitates B Only CaSO 3 precipitates C Both CaSO 3 and Na 2 S precipitate D No precipitate forms 18 Consider the solubility equilibrium: SrCO 3 () s Sr 2+ ( aq) + CO 2 3 ( aq) The addition of which of the following substances will cause the equilibrium to shift right? A HCl ( aq) B SrCO 3 () s C Na 2 CO 3 ( aq) D Sr ( NO 3 ) 2 ( aq) Page 8 Chemistry Form A

11 19 Given the precipitation reaction: Na 2 Saq ( ) + Fe ( NO 3 ) 2 ( aq) FeS()+ s 2NaNO 3 ( aq) What is the K sp expression for the saturated solution formed? A K sp = Fe2+ S 2 FeS B K sp = Fe 2+ S 2 C K sp = D K sp = Fe 2+ FeS S 2 1 Fe 2+ S 2 20 What is the K sp for the salt Pb( IO 3 ) 2 if its solubility is M? A B C D What is the maximum [ IO 3 ] that can exist in a MCu 2+ solution? A M B M C M D M Chemistry Form A Page 9

12 22 Which of the following represents the results of tests on an acidic solution? Reaction with Mg() s Colour with Neutral Red A yes red B yes amber C no red D no amber 23 Which of the following represents a protonated water molecule? A H 2 O B H 3 O C H 2 O + D H 3 O + 24 Which of the following best describes a weak base? K b % Ionization A very small low B very small high C very large low D very large high 25 Which species will produce the greatest hydroxide ion concentration in solution? A + NH 4 B 3 PO 4 C HCO 3 D H 2 CO 3 Page 10 Chemistry Form A

13 26 Water will react most completely as an acid with 2 A SO 3 B H 2 BO 3 C C 6 H 5 O D CH 3 COO Use the following equilibrium equation to answer questions 27 and 28 energy + 2H 2 O( ) H 3 O + ( aq) + OH ( aq) 27 What does this equation represent? A K w B the ionization of water C the ion product of water D the equilibrium expression for water 28 Which of the following is correct for water? Temperature ph Solution Type A increases increases neutral B increases decreases acidic C increases decreases neutral D decreases increases basic Chemistry Form A Page 11

14 29 What is the ph of 050 M LiOH? A B 030 C 030 D What is the equilibrium constant expression for the predominant equilibrium in NaHSO 3 ( aq)? A B H 3 O + SO 3 HSO 3 2 H 2 SO 3 OH HSO 3 C NaHSO 3 ( aq) Na + ( aq) + HSO 3 ( aq) D HSO 3 ( aq) + H 2 O( ) H 3 O + ( aq) + SO 2 3 ( aq) 31 Which of the following 010 M solutions would have the lowest ph? A HF B NH 3 C HNO 3 D H 2 CO 3 Page 12 Chemistry Form A

15 32 Which of the following describes a solution of LiClO 4 ( aq) with respect to hydrolysis? A Li + ( aq) + H 2 O( ) LiOH ( aq) + H + ( aq) B LiClO 4 ( aq) + H 2 O( ) LiOH( aq) + HClO 4 ( aq) C ClO 4 ( aq) + H 2 O( ) HClO 4 ( aq) + OH ( aq) D No hydrolysis reaction occurs 33 Which of the following is a basic salt solution? A NH 3 ( aq) B NH 4 Iaq ( ) C KNO 3 ( aq) D Na 2 CO 3 ( aq) 34 A chemical indicator typically A changes colour when acid or base is added B resists changes in ph when acid or base is added C resists changes in colour when acid or base is added D neutralizes acids and indicates this with a colour change 35 A solution was tested with two indicators and the following results were obtained: Indicator methyl red thymol blue Colour yellow yellow The approximate ph of the solution is A 52 B 60 C 94 D 106 Chemistry Form A Page 13

16 36 What is the net ionic equation for the reaction of nitric acid with NaOH ( aq)? A H + ( aq) + OH ( aq) H 2 O( ) B HNO 3 ( aq) + NaOH ( aq) NaNO 3 ( aq) + H 2 O( ) C HNO 3 ( aq) + NaOH ( aq) + H 2 O( ) NaNO 3 ( aq) + H 3 O + ( aq) + OH ( aq) D H + ( aq) + NO 3 ( aq) + Na + ( aq) + OH ( aq) Na + ( aq) + NO 3 ( aq) + H 2 O( ) 37 Consider the following buffer equilibrium system: H 2 CO 3 ( aq) + H 2 O( ) H 3 O + ( aq) + HCO 3 ( aq) What is the net result of adding a small amount of HCl? A The H 3 O + increases slightly B The ph remains the same C The ph increases slightly D The H 2 CO 3 decreases slightly 38 An oxide of which of the following elements will form a solution that acts only as a base? A P B N C Zn D Ba 39 An oxidized substance A is the reducing agent and loses electrons B is the reducing agent and gains electrons C is the oxidizing agent and loses electrons D is the oxidizing agent and gains electrons Page 14 Chemistry Form A

17 40 Consider the following redox equation: 6H 2 SO 4 + 2KIO FeSO 4 5Fe 2 ( SO 4 ) 3 + I 2 + 6H 2 O + K 2 SO 4 Which species is the reducing agent? A I from KIO 3 B S from H 2 SO 4 C H from H 2 SO 4 D Fe from FeSO 4 41 What is the oxidation number of CinNaC 7 H 5 O 2? A 4 B 2 C 2 7 D Consider the following spontaneous redox equations: X + Y X + Y + Y + + Z Y + Z + Z + X Z + + X Which of the following describes the relative strengths of the oxidizing agents? A Z > Y > X B X > Y > Z C X > Y + > Z + D Z + > Y + > X Chemistry Form A Page 15

18 43 Consider the following skeletal redox reaction in basic solution: MnO 4 + Mn 2+ MnO 2 Which of the following is the reduction half-reaction? A 2e + 4OH + Mn 2+ MnO 2 + 2H 2 O B 4OH + Mn 2+ MnO 2 + 2H 2 O + 2e C 3e + 2H 2 O + MnO 4 MnO 2 + 4OH D 4e + 2H 2 O + MnO 4 MnO 2 + 4OH 44 Pure H 3 AsO 3 solid can be used to standardize a KMnO 4 solution using a redox titration as follows: 3H 2 SO 4 + 2KMnO 4 + 5H 3 AsO 3 2MnSO 4 + 5H 3 AsO 4 + 3H 2 O + K 2 SO 4 A 0200 g sample of H 3 AsO 3 was titrated with 146mL of KMnO 4 solution What is the molarity of the KMnO 4 solution? A 00435M B 0109 M C 0272 M D 548 M Page 16 Chemistry Form A

19 45 Consider the following diagram of a standard electrochemical cell: H 2 (g) e Object 1 e Metal X Porous Barrier Metal Z 10 M HCl 10 M Z(NO 3 ) 2 Which of the following is correct as the cell operates? Object 1 Metal X A voltmeter anode B voltmeter cathode C power supply anode D power supply cathode Chemistry Form A Page 17

20 Use the following electrochemical cell diagram to answer questions 46, 47 and 48 Volts 10 M KNO3 Sn Fe 10 M Sn(NO 3 ) 2 10 M Fe(NO 3 ) 2 46 What is the cathode half-cell reaction? A Sn e Sn B Fe e Fe C Fe 2+ + e Fe 3+ D Sn e Sn Which of the following correctly describes the operating cell? Direction of Positive Ion Migration Reducing Agent A towards Sn Sn B towards Sn Fe C towards Fe Sn D towards Fe Fe 48 What would be observed if the solution in the U-tube was replaced with 10 M K 2 S, leaving all of the other components the same? Sn Half-cell Fe Half-cell A precipitate precipitate B precipitate no precipitate C no precipitate precipitate D no precipitate no precipitate Page 18 Chemistry Form A

21 49 An iron pipeline can be protected from rusting by connecting it to a A zinc nitrate solution B silver nitrate solution C zinc electrode buried beside the pipeline D silver electrode buried beside the pipeline 50 What products result from the electrolysis of molten KBr? Product at the Cathode Product at the Anode A K O 2 B K Br 2 C O 2 H 2 D Br 2 K You have Examination Booklet Form A In the box above #1 on your Answer Sheet, ensure you filled in the bubble as follows Exam Booklet Form/ Cahier d examen A B C D E F G H This is the end of the multiple-choice section Answer the remaining questions in the Response Booklet Chemistry Form A Page 19

22

23 PERIODIC TABLE OF THE ELEMENTS Be Beryllium 90 5 B Boron C Carbon N Nitrogen O Oxygen F Fluorine H He Hydrogen Helium Ne Neon Atomic Number Symbol Name Atomic Mass 3 Li Lithium i Si i i Silicon Na Mg Sodium Magnesium Aluminum Silicon Phosphorus Sulphur Chlorine Argon Al Si P S Cl Ar K Ca Sc Ti V Cr Mn Fe Co Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton Ni Cu Zn Ga Ge As Se Br Kr Rb Y Zr Nb Mo Tc Ru Rh Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon (98) Sr Pd Ag Cd In Sn Sb Te I Xe Cs Ba La Hf Ta W Re Os Ir Cesium Barium Lanthanum Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury Thallium Lead Bismuth Polonium Astatine Radon (209) (210) (222) Pt Au Hg Tl Pb Bi Po At Rn Fr Ra Ac Rf Db Francium Radium Actinium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium (223) (226) (227) (261) (262) (263) (262) (265) (266) Sg Bh Hs Mt 58 Ce Cerium Based on mass of C 12 at Th Thorium Pr Praseodymium Pa Protactinium Nd Neodymium U Uranium Pm Promethium (145) 93 Np Neptunium (237) 62 Sm Samarium Pu Plutonium (244) 63 Eu Europium Am Americium (243) 64 Gd Gadolinium Cm Curium (247) 65 Tb Terbium Bk Berkelium (247) 66 Dy Dysprosium Cf Californium (251) 67 Ho Holmium Es Einsteinium (252) 68 Er Erbium Fm Fermium (257) 69 Tm Thulium Md Mendelevium (258) 70 Yb Ytterbium No Nobelium (259) 71 Lu Lutetium Lr Lawrencium (262) Values in parentheses are the masses of the most stable or best known isotopes for elements which do not occur naturally Chemistry 12 Data Page 1

24 ATOMIC MASSES OF THE ELEMENTS Based on mass of C 12 at 1200 Values in parentheses are the mass number of the most stable or best known isotopes for elements that do not occur naturally Data Page 2 Chemistry 12 Actinium Aluminum Americium Antimony Argon Arsenic Astatine Barium Berkelium Beryllium Bismuth Boron Bromine Cadmium Calcium Californium Carbon Cerium Cesium Chlorine Chromium Cobalt Copper Curium Dubnium Dysprosium Einsteinium Erbium Europium Fermium Fluorine Francium Gadolinium Gallium Germanium Gold Hafnium Helium Holmium Hydrogen Indium Iodine Iridium Iron Krypton Lanthanum Lawrencium Lead Lithium Lutetium Magnesium Manganese Mendelevium Ac Al Am Sb Ar As At Ba Bk Be Bi B Br Cd Ca Cf C Ce Cs Cl Cr Co Cu Cm Db Dy Es Er Eu Fm F Fr Gd Ga Ge Au Hf He Ho H In I Ir Fe Kr La Lr Pb Li Lu Mg Mn Md (227) 270 (243) (210) 1373 (247) (251) (247) (262) 1625 (252) (257) 190 (223) (262) (258) Mercury Molybdenum Neodymium Neon Neptunium Nickel Niobium Nitrogen Nobelium Osmium Oxygen Palladium Phosphorus Platinum Plutonium Polonium Potassium Praseodymium Promethium Protactinium Radium Radon Rhenium Rhodium Rubidium Ruthenium Rutherfordium Samarium Scandium Selenium Silicon Silver Sodium Strontium Sulphur Tantalum Technetium Tellurium Terbium Thallium Thorium Thulium Tin Titanium Tungsten Uranium Vanadium Xenon Ytterbium Yttrium Zinc Zirconium Hg Mo Nd Ne Np Ni Nb N No Os O Pd P Pt Pu Po K Pr Pm Pa Ra Rn Re Rh Rb Ru Rf Sm Sc Se Si Ag Na Sr S Ta Tc Te Tb Tl Th Tm Sn Ti W U V Xe Yb Y Zn Zr (237) (259) (244) (209) (145) 2310 (226) (222) (261) (98) Element Symbol Atomic Number Atomic Mass Element Symbol Atomic Number Atomic Mass

25 NAMES, FORMULAE, AND CHARGES OF SOME COMMON IONS * Aqueous solutions are readily oxidized by air ** Not stable in aqueous solutions Positive Ions (Cations) Al 3+ Aluminum Pb 4+ Lead(IV), plumbic NH 4 + Ammonium Li + Lithium Ba 2+ Barium Mg 2+ Magnesium Ca 2+ Calcium Mn 2+ Manganese(II), manganous Cr 2+ Chromium(II), chromous Mn 4+ Manganese(IV) Cr 3+ Chromium(III), chromic Hg 2 2+ Mercury(I)*, mercurous Cu + Copper(I)*, cuprous Hg 2+ Mercury(II), mercuric Cu 2+ Copper(II), cupric K + Potassium H + Hydrogen Ag + Silver H 3 O + Hydronium Na + Sodium Fe 2+ Iron(II)*, ferrous Sn 2+ Tin(II)*, stannous Fe 3+ Iron(III), ferric Sn 4+ Tin(IV), stannic Pb 2+ Lead(II), plumbous Zn 2+ Zinc Negative Ions (Anions) Br Bromide OH Hydroxide CO 3 2 Carbonate ClO Hypochlorite ClO 3 Chlorate I Iodide Cl Chloride HPO 4 2 Monohydrogen phosphate ClO 2 Chlorite NO 3 Nitrate CrO 4 2 Chromate NO 2 Nitrite CN Cyanide C 2 O 4 2 Oxalate Cr 2 O 7 2 Dichromate O 2 Oxide** H 2 PO 4 Dihydrogen phosphate ClO 4 Perchlorate CH 3 COO Ethanoate, acetate MnO 4 Permanganate F Fluoride PO 4 3 Phosphate HCO 3 Hydrogen carbonate, bicarbonate SO 4 2 Sulphate HC 2 O 4 Hydrogen oxalate, binoxalate S 2 Sulphide HSO 4 Hydrogen sulphate, bisulphate SO 3 2 Sulphite HS Hydrogen sulphide, bisulphide SCN Thiocyanate HSO 3 Hydrogen sulphite, bisulphite Chemistry 12 Data Page 3

26 SOLUBILITY OF COMMON COMPOUNDS IN WATER The term soluble here means > 01 mol/l at 25 C Negative Ions (Anions) Positive Ions (Cations) Solubility of Compounds All Alkali ions: Li +, Na +, K +, Rb +, Cs +, Fr + Soluble All Hydrogen ion: H + Soluble All Ammonium ion: NH 4 + Soluble Nitrate, NO 3 All Soluble or or Chloride, Cl Bromide, Br Iodide, I All others Ag +, Pb 2+, Cu + Soluble Low Solubility Sulphate, SO 4 2 All others Ag +, Ca 2+, Sr 2+, Ba 2+, Pb 2+ Soluble Low Solubility Sulphide, S 2 Alkali ions, H +, NH 4 +, Be 2+, Mg 2+, Ca 2+, Sr 2+, Ba 2+ All others Soluble Low Solubility Hydroxide, OH Alkali ions, H +, NH + 4, Sr 2+ All others Soluble Low Solubility or or Phosphate, PO 4 3 Carbonate, CO 3 2 Sulphite, SO 3 2 Alkali ions, H +, NH 4 + All others Soluble Low Solubility Data Page 4 Chemistry 12

27 SOLUBILITY PRODUCT CONSTANTS AT 25 C Name Barium carbonate Barium chromate Barium sulphate Calcium carbonate Calcium oxalate Calcium sulphate Copper(I) iodide Copper(II) iodate Copper(II) sulphide Iron(II) hydroxide Iron(II) sulphide Iron(III) hydroxide Lead(II) bromide Lead(II) chloride Lead(II) iodate Lead(II) iodide Lead(II) sulphate Magnesium carbonate Magnesium hydroxide Silver bromate Silver bromide Silver carbonate Silver chloride Silver chromate Silver iodate Silver iodide Strontium carbonate Strontium fluoride Strontium sulphate Zinc sulphide Formula BaCO 3 BaCrO 4 BaSO 4 CaCO 3 CaC 2 O 4 CaSO 4 CuI Cu(IO 3 ) 2 CuS Fe(OH) 2 FeS Fe(OH) 3 PbBr 2 PbCl 2 Pb(IO 3 ) 2 PbI 2 PbSO 4 MgCO 3 Mg(OH) 2 AgBrO 3 AgBr Ag 2 CO 3 AgCl Ag 2 CrO 4 AgIO 3 AgI SrCO 3 SrF 2 SrSO 4 ZnS K sp Chemistry 12 Data Page 5

28 RELATIVE STRENGTHS OF BRØNSTED-LOWRY ACIDS AND BASES in aqueous solution at room temperature Name of Acid Acid Base K a STRONG STRENGTH OF ACID WEAK 4 4 Perchloric HClO Æ H + ClO Hydriodic HI Æ H + I Hydrobromic HBr Æ H + Br Hydrochloric HCl Æ H + Cl 3 3 Nitric HNO Æ H + NO very large very large very large very large very large Sulphuric H2SO4 Æ H + HSO4 very large + + Hydronium Ion H3O Æ H + H2O 10 - Iodic HIO3 Æ H + IO Oxalic H C O Æ H + HC O Sulphurous ( SO2 + H2O) H2SO3 Æ H + HSO3 Hydrogen sulphate ion HSO4 Æ H + SO Phosphoric H PO Æ H + H PO Hexaaquoiron ion iron III ion Fe( H2O) 6 Æ H + Fe( H2O) ( OH) +, ( ) 5 Citric H3C6H5O7 Æ H + H2C6H5O7 Nitrous HNO2 Æ H + NO Hydrofluoric HF Æ H + + F Methanoic, formic HCOOH Æ H + HCOO Hexaaquochromium ion, chromium( III) ion Cr( H2O) Æ H + Cr( H O) ( OH) Benzoic C6H5COOH Æ H + C6H5COO Hydrogen oxalate ion HC2O4 Æ H + C2O4 Ethanoic, acetic CH COOH 3 H CH3COO Dihydrogen citrate ion H C H O Æ H + HC H O Hexaaquoaluminum ion, aluminum ion Al( H O) Æ H + Al( H O) ( OH) Carbonic ( CO2 + H2O) H2CO3 Æ H + HCO Monohydrogen citrate ion 2- + HC6H5O7 Æ H + CHO Hydrogen sulphite ion HSO3 Æ H + SO Hydrogen sulphide H2S Æ H + HS Dihydrogen phosphate ion H2PO4 Æ H + HPO Boric H3BO3 Æ H + H2BO Ammonium ion NH4 Æ H + NH Hydrocyanic HCN Æ H + CN Phenol C6H5OH Æ H + C6H5O Hydrogen carbonate ion HCO3 Æ H + CO Hydrogen peroxide H2O2 Æ H + HO Monohydrogen phosphate ion 2- HPO4 Æ H + PO Water H O Æ H + OH Hydroxide ion 2 - OH H + O very small 3 2 Ammonia NH H + NH very small 14 WEAK STRENGTH OF BASE STRONG Data Page 6 Chemistry 12

29 ACID-BASE INDICATORS Indicator Methyl violet Thymol blue Orange IV Methyl orange Bromcresol green Methyl red Chlorophenol red Bromthymol blue Phenol red Neutral red Thymol blue Phenolphthalein Thymolphthalein Alizarin yellow Indigo carmine ph Range in Which Colour Change Occurs Colour Change as ph Increases yellow to blue red to yellow red to yellow red to yellow yellow to blue red to yellow yellow to red yellow to blue yellow to red red to amber yellow to blue colourless to pink colourless to blue yellow to red blue to yellow Chemistry 12 Data Page 7

30 STANDARD REDUCTION POTENTIALS OF HALF-CELLS Ionic concentrations are at 1M in water at 25 C Oxidizing Agents Reducing Agents - - F2 ( g)+ 2e Æ 2F SO e Æ 2SO HO H + 2e Æ 2HO MnO4 + 8H + 5e Æ Mn + 4H2O Au + 3e Æ Au() s BrO3 + 6H + 5e Æ 2 Br2()+ l 3H2O ClO4 + 8H + 8e Æ Cl + 4H2O Cl2( g)+ 2e Æ - 2Cl Cr2O H + 6e Æ 2Cr + 7H2O O2( g)+ 2H + 2e Æ HO MnO2()+ s 4H + 2e Æ Mn + 2H2O IO3 + 6H + 5e Æ 2 I2()+ s 3H2O Overpotential Br2 ()+ l 2e Æ 2Br Effect AuCl4 + 3e Æ Au()+ s 4Cl NO3 + 4H + 3e Æ NO( g)+ 2H2O Hg + 2e Æ Hg() l O ( g )+ 2H ( 10 M)+ 2e Æ H2O NO3 + 4H + 2e Æ N2O4 + 2H2O Ag + e Æ Ag() s Hg2 + e Æ Hg() l Fe + e Æ 2+ Fe O2( g)+ 2H + 2e Æ H2O MnO4 + 2H2O + 3e Æ MnO2()+ s 4OH I2()+ s 2e Æ - 2I Cu + e Æ Cu() s HSO H + 4e Æ Ss ()+ 3HO Cu + 2e Æ Cu() s SO4 + 4H + 2e Æ H2SO3 + H2O Cu + e Æ + Cu Sn + 2e Æ 2+ Sn Ss ()+ 2H + 2e Æ H2Sg ( ) H + 2e Æ H2( g) Pb + 2e Æ Pb() s Sn + 2e Æ Sn() s Ni + 2e Æ Ni() s -026 HPO H + 2e Æ HPO HO Co + 2e Æ Co() s -028 Se()+ s 2H + 2e Æ H2Se Cr + e Æ 2+ Cr HO 2 + 2e Æ H2 + 2OH ( 10 M) Fe + 2e Æ Fe() s -045 Overpotential - 2- Ag2S()+ s 2e Æ 2Ag()+ s S -069 Effect 3 Cr + 3e Æ Cr() s Zn + 2e Æ Zn() s -076 Te()+ s 2H + 2e Æ H2Te HO 2 + 2e Æ H2( g)+ 2OH Mn + 2e Æ Mn() s Al + 3e Æ Al() s Mg + 2e Æ Mg() s -237 Na + e Æ Na() s Ca + 2e Æ Ca() s Sr + 2e Æ Sr() s Ba + 2e Æ Ba() s -291 K + e Æ K() s -293 Rb + e Æ Rb() s -298 Cs + e Æ Cs() s -303 Li + e Æ Li() s -304 Data Page 8 Chemistry 12 STRONG STRENGTH OF OXIDIZING AGENT WEAK E ( Volts ) WEAK STRENGTH OF REDUCING AGENT STRONG

31 MINISTRY USE ONLY MINISTRY USE ONLY Question (5) NR Question (5) NR Place Personal Education Number (PEN) here Question (5) NR Question 4 Course Code = CH /08 RELEASED EXAM AUGUST 2008 Exam Booklet, Form/ Cahier d examen A B C D E F G H Question Question (5) (5) NR NR (5) NR Student Instructions Question 7 1 Place your Personal Education Number (PEN) label at the top of this Booklet AND fill in the bubble (Form A, B, C, D, E, F, G or H) that corresponds to the letter on your Examination Booklet Question (5) (5) NR NR 2 Use a pencil to fill in bubbles when answering questions on your Answer Sheet 3 Use a pencil or blue- or black-ink pen when answering written-response questions in this Booklet 4 Read the Examination Rules on the back of this Booklet 814 Version 06011

32 MINISTRY USE ONLY Place Personal Education Number (PEN) here Course Code = CH 12 Chemistry /08 RELEASED EXAM AUGUST 2008 Response Booklet Province of British Columbia

33 PART B: WRITTEN RESPONSE Value: 375% of the examination Suggested Time: 40 minutes 1 (4 marks) Solid sodium bicarbonate and acetic acid were reacted in an open flask as follows: NaHCO 3 ()+ s CH 3 COOH ( aq) NaCH 3 COO ( aq) + H 2 O( ) + CO 2 ( g) The following data was recorded: Time (s) Mass of Flask and Contents (g) g g g g Calculate the overall rate of reaction in grams of NaHCO 3 per minute Chemistry Response Booklet Page 1

34 2 (4 marks) Consider the following equilibrium: O 2 ( g) + 2F 2 ( g) 2OF 2 ( g) Initially, some OF 2 was placed in a 10 L container and allowed to react The amount of OF 2 was monitored over 4 minutes and the following graph was produced: [OF ] 2 mol ( L ) Time (min) Calculate the value of K eq Page 2 Chemistry Response Booklet

35 3 (4 marks) Consider the equilibrium for a saturated solution of PbI 2 : PbI 2 () s Pb 2+ ( aq) + 2I ( aq) What is the maximum Ag + that can exist in a saturated solution of PbI 2 without causing a precipitate to form? Chemistry Response Booklet Page 3

36 4 (3 marks) Complete the following equilibrium, then predict whether the reactants or products will be favoured and explain why HSO 4 + HSO 3 5 (5 marks) Calculate the initial concentration of a KF salt solution that has a ph = 865 Begin by writing the equation for the predominant equilibrium reaction Page 4 Chemistry Response Booklet

37 6 (3 marks) In three separate trials, 1000 ml samples of H 2 SO 4 were titrated with 040 M NaOH and the results are tabulated below Trial Volume of 040 M NaOH ml ml ml Calculate the concentration of the H 2 SO 4 Chemistry Response Booklet Page 5

38 7 (4 marks) Balance the following redox equation in basic solution: O 2 + Co( NH 3 ) Co( NH 3 ) 6 (basic) 8 (3 marks) A solution of MnSO 4 is electrolyzed using inert electrodes Write the anode and cathode half-reactions and describe any observations at the cathode Anode half-reaction: Cathode half-reaction: Cathode observation: Page 6 Chemistry Response Booklet

39

40 Examination Rules 1 The time allotted for this examination is two hours You may, however, take up to 60 minutes of additional time to finish 2 Answers entered in the Examination Booklet will not be marked 3 Cheating on an examination will result in a mark of zero The Ministry of Education considers cheating to have occurred if students break any of the following rules: Students must not be in possession of or have used any secure examination materials prior to the examination session Students must not communicate with other students during the examination Students must not give or receive assistance of any kind in answering an examination question during an examination, including allowing one s paper to be viewed by others or copying answers from another student s paper Students must not possess any book, paper or item that might assist in writing an examination, including a dictionary or piece of electronic equipment, that is not specifically authorized for the examination by ministry policy Students must not copy, plagiarize or present as one s own, work done by any other person Students must immediately follow the invigilator s order to stop writing at the end of the examination time and must not alter an Examination Booklet, Response Booklet or Answer Sheet after the invigilator has asked students to hand in examination papers Students must not remove any piece of the examination materials from the examination room, including work pages 4 The use of inappropriate language or content may result in a mark of zero being awarded 5 Upon completion of the examination, return all examination materials to the supervising invigilator