Carefully detach the last page. It is the Data Sheet.

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1 HM 13 NWS XM 005 UNIVRSITY OF WTRLOO PRTMNT OF HMISTRY 11 MY 005 TIM: 75 MINUTS This exam is being written by several thousand students. Please be sure that you follow the instructions below. We'll send you a report on your performance. Top performers are eligible for a prize. 1. Print your name here:. Print your school name and city on your STUNT RSPONS sheet. 3. Select, and enter on the STUNT RSPONS sheet, one of the following O numbers: ode 1 ode ode 3 ode 4 ode 5 ode 6 ode 7 ode 8 Ontario, now studying Grade 1 hemistry in a nonsemestered school Ontario, now studying Grade 1 hemistry in a semestered school Ontario, Grade 1 hemistry already completed ny other Ontario student Manitoba or Saskatchewan high school student Québec high school student Québec GP student lberta or ritish olumbia high school student ode 9 New runswick, Newfoundland, Nova Scotia, or Prince dward Island high school student ode 10 Northwest Territories, Nunavut, or Yukon high school student 4. Print your name (last name, first name and optional middle initial) on the STUNT RSPONS sheet. lso fill in the corresponding circles below your printed name. 5. arefully detach the last page. It is the datasheet. 6. Now answer the exam questions. Questions are not in order of difficulty. Indicate your choice on the STUNT RSPONS sheet by marking one letter beside the question number. Mark only one answer for each question. Questions are all of the same value. There is a penalty (1/4 off) for each incorrect answer, but no penalty if you do not answer. 7. Take care that you make firm, black pencil marks, just filling the oval. e careful that any erasures are complete make the sheet white again. ode 11 High school student outside anada ode 1 Teacher arefully detach the last page. It is the ata Sheet.

2 HM 13 NWS XM nswers 1 What is the ground-state electron configuration of an isolated manganese (Mn) atom? 5 Which one of the following is a structural isomer of butanal? [r] 4d 7 H 3 H H H OH * [r] 4s 3d 5 [r] 4s 1 4p 6 * H 3 OH H 3 H 3 H H H 3 [r] 4s 4p 5 H 3 H H OOH [r] 3d 7 H 3 H OH H 3 How many electrons does it take to fill the n = 4 shell of an atom? two eight fourteen eighteen * thirty-two 3 How many unpaired electrons are there in a phosphorus atom (P), assuming the atom is in its ground electronic state? one two * three four five 6 Which of the following correctly characterizes the bonds and geometry of the H 4 molecule? four σ bonds, two π bonds and an H--H bond angle very close to 10 o six σ bonds, no π bonds and an H--H bond angle very close to 90 o five σ bonds, one π bond and an H--H bond angle very close to 109 o * five σ bonds, one π bond and an H--H bond angle very close to 10 o six σ bonds, no π bonds and an H--H bond angle very close to 10 o 7 In which of the following is the nitrogen-to-nitrogen distance the smallest? - N - N 3 N H 4 4 Which of the following ions has the largest ionic radius? Na + Mg + * N 3 O F N H * N 8 Which of the following compounds contains ionic bonds only? Il 3 F O NH 4 l * Mgl HF / HM 13 NWS XM 005 UNIVRSITY OF WTRLOO

3 9 Which of the following molecules is not linear? HN * O 3 H ef O 10 What is the molecular geometry of XeF 4? (Xe is the central atom.) see-saw * square planar T-shaped tetrahedral trigonal pyramidal 11 Which of the following molecules does not possess a permanent dipole moment? 13 The boiling points of H 4 and l 4 are -16 o and 77 o, respectively. Why is the boiling point of l 4 so much higher than that of H 4? H 4 is a molecular compound and l 4 is an ionic compound. The -H bond in H 4 is much weaker than the -l bond in l 4. The dipole-dipole forces between H 4 molecules are much less attractive than the dipole-dipole forces between l 4 molecules. The -H bond in H 4 is much less polar than the -l bond in l 4. * The London dispersion forces between H 4 molecules are much less attractive than the London dispersion forces between l 4 molecules. 14 The compound represented by the structural formula H 3 H O is most readily synthesized from O H 3 H S H 3 H 3, O and H 4 F O H 3 H H OH and H 3 OH * XeF H 4 and H 3 H OOH H O * H 3 OH and H 3 H OOH SO H 3 H OH and H 3 OOH 1 Which compound has the lowest boiling point? * H ==H H 3 H NH H 3 -O-H 3 H 3 HO H 3 H OH 15 When aqueous sodium carbonate, Na O 3, is treated with dilute hydrochloric acid, Hl, the products are sodium chloride, water and carbon dioxide gas. What is the net ionic equation for this reaction? H + (aq) + OH (aq) H O(l) Na + (aq) + l (aq) Nal(s) * H + (aq) + O 3 (aq) O (g) + H O(l) Hl(aq) + O 3 (aq) O (g) + H O(l) + l (aq) Na O 3 (aq) + H + (aq) Na + (aq) + O (g) + H O(l) 005 UNIVRSITY OF WTRLOO HM 13 NWS XM / 3

4 16 In acidic aqueous solution, dichromate ion (r O 7 ) and chloride ion (l ) react to give r 3+ and l. The unbalanced chemical equation for the reaction is given below. - 7 x r O + y l m r 3+ + n l When the equation is properly balanced, what is the ratio x : y? 19 The molar enthalpies of combustion of H 3 OOOH(l ), H 3 OOH(l ) and O(g) are, respectively, 175 kj mol 1, 875 kj mol 1 and 83 kj mol 1. What is the enthalpy change for the reaction below? H 3 OOOH(l ) H 3 OOH(l ) + O(g) 1867 kj 1:1 1: 1867 kj 117 kj 1:3 * 117 kj :3 * 1:6 433 kj 17 The element M forms the compound Ml 4. If the compound is approximately 75% l by mass, then what is M? Si The molar mass of l is g mol 1. 0 For the elementary process shown below, the activation energy is 17 kj mol 1 and the enthalpy change is 173 kj mol 1. OH + H H O + H What is the activation energy for the reverse process? * 190 kj mol 1 * Ti 190 kj mol 1 Se 173 kj mol 1 Pt 156 kj mol kj mol 1 18 What is H o for the gas-phase reaction below? H 4 (g) + l (g) H 3 l(g) + Hl(g) 113 kj * 113 kj 63 kj 63 kj 147 kj ond dissociation energies (in kj mol 1 ) l-l 43 -l 339 H-l 431 H The decomposition of cyclopropane is a first-order reaction with rate constant (k) equal to min 1 at 450 o. How long does it take for 75% of a sample of cyclopropane to decompose at 450 o? 4.5 min 5.1 min 1 min 18 min * 5 min 4 / HM 13 NWS XM 005 UNIVRSITY OF WTRLOO

5 The reaction below was carried out several times in order to determine the rate equation. NO(g) + H (g) N O(g) + H O(g) The following data were obtained. (oncentrations are in mol L 1 and the initial rate is in mol L 1 s 1.) [NO] [H ] Initial Rate xpt xpt xpt solution of Hl is prepared by diluting L of a stock Hl solution to 6.0 L. If it takes 10.0 ml of the diluted Hl solution to neutralize 0.0 ml of 0.5 mol L 1 NaOH solution, then what was the concentration of the undiluted stock solution? 0.04 mol L mol L 1.5 mol L 1 What is the rate law for the reaction? 3.0 mol L 1 Rate = k [NO] [H ] * 6.0 mol L 1 Rate = k [NO] [H ] * Rate = k [NO] [H ] Rate = k [NO] [H ] Rate = k [NO] 3 [H ] 3 onsider the reversible elementary process below. k 1 k 1 k 1 and k 1 are the rate constants for the forward and reverse reactions. If K c denotes the equilibrium constant for the reaction, then which of the following conditions is satisfied when the process above reaches a state of dynamic equilibrium? 6 The reaction below comes to equilibrium in a closed reaction vessel of volume.50 L. NO(g) + O (g) NO (g) t equilibrium, there are 3.0 mol NO, 4.00 mol O, and.0 mol NO. What is the value of K c? * k 1 = k 1 k 1 = k 1 K c = k 1 k 1 * K = k / k c 1-1 K c = k 1 + k 1 4 What is the ph of mol L 1 H looh(aq) at 5 o? (K a = for H looh) 7 The equilibrium constant for the reaction below is K c = at 5 o. If the initial concentrations were [N ] = [ H ] = [HN] = 1.00 mol L 1, then what is [HN] at equilibrium? N (g) + H (g) HN(g) mol L 1 * mol L * mol L mol L mol L UNIVRSITY OF WTRLOO HM 13 NWS XM / 5

6 8 The following reaction reaches equilibrium in a closed reaction vessel. 3 Fe(s) + 4 H O(g) Fe 3 O 4 (s) + 4 H (g) Which of the following actions changes the value of the equilibrium constant? reducing the volume of the reaction vessel adding some Fe(s) * increasing the temperature adding a catalyst removing some H (g) ml sample of a (H 3 ) 3 N(aq) solution was titrated with 0.15 mol L 1 Hl(aq). The titration curve is shown below. What was the initial concentration of the (H 3 ) 3 N solution? ph Two titrations are carried out at 5 o as shown below. strong base V (in ml) * 0.18 mol L mol L mol L mol L 1 Flask ml of 0.10 mol L 1 weak monoprotic acid Flask 5.0 ml of 0.10 mol L 1 strong monoprotic acid 0.5 mol L 1 Which of the following statements is true? The weak acid requires less base than the strong acid to reach the equivalence point. The weak acid requires more base than the strong acid to reach the equivalence point. The ph at equivalence is 7.00 for both titrations. t the respective equivalence points, the ph of the solution in flask 1 is less than the ph of the solution in flask. * t the respective equivalence points, the ph of the solution in flask 1 is greater than the ph of the solution in flask. 31 Which of the following substances or mixtures produces the highest ph when dissolved in water to make 1.0 L of solution at 5 o? 1.00 mol HNO * 1.00 mol NaNO 0.50 mol HNO plus 0.50 mol NaNO K a = for HNO 0.50 mol HNO plus 0.5 mol NaOH 0.50 mol HNO plus 0.50 mol NaOH 6 / HM 13 NWS XM 005 UNIVRSITY OF WTRLOO

7 3 For Li 3 PO 4 (s), K sp = at 98 K. What is the solubility of Li 3 PO 4 in water at 98 K? 36 onsider the galvanic cell shown below. The temperature is 5 o mol L 1 platinum wire mol L mol L 1 Ni(s) salt bridge Pb(s) * mol L mol L 1 33 What is the equilibrium concentration of g + in solution when 0.50 L of 0.10 mol L -1 gno 3 (aq) and 0.50 L of 0.0 mol L -1 Nal(aq) are mixed? 0 mol L mol L -1 * mol L -1 K sp = for gl 1.0 mol L -1 Ni(NO 3 ) (aq) 1.0 mol L -1 Pb(NO 3 ) (aq) The relevant half-reactions and standard reduction potentials are: Pb + (aq) + e - Pb(s) Ni + (aq) + e - Ni(s) o = volts o = volts Which one of the following statements is true? mol L mol L What is the oxidation state of l in HlO? 0 The Pb electrode is the anode. t equilibrium, the cell potential is volts. The standard cell potential is volts. Positive ions in the salt bridge migrate towards, and then diffuse into, the Ni(NO 3 ) solution. 1 * t equilibrium, [Ni + ] is greater than 1.0 mol L * Which of the following statements concerning the Lewis structure below is true? H O l O The l atom is sp hybridized. * The O-l-O bond angle is very close to the ideal tetrahedral bond angle of 109 o. 37 Which of the following will reduce H + to H in aqueous solution under standard conditions? * Ni(s) Half-reaction o (in volts) F (g) + e F (aq).889 u + (aq) + e u(s) r (l) + e r (aq) H + (aq) + e H (g) 0.0 Ni + (aq) + e Ni(s) 0.36 Zn + (aq) + e Zn(s) 0.76 u(s) The H-O-l bond angle is 180 o. r (l) This structure is unrealistic because the l atom does not obey the octet rule. The l atom is sp hybridized. F (aq) Zn + (aq) 005 UNIVRSITY OF WTRLOO HM 13 NWS XM / 7

8 38 What mass of chromium metal will be deposited if a current of 0.57 amperes is passed through a solution of r(no 3 ) 3 for 45 minutes? g * 0.76 g 0.89 g 1.33 g 1 ampere = 1 coulomb per second Faraday s constant: F = coulombs per mole tomic weight of r, g 39 What is the value of K c for the reaction below? HNO (aq) + NH 3 (aq) NO (aq) + + NH 4 (aq) * K a = for HNO K b = for NH 3 K w = n aqueous solution of HOH H OH has a density of g ml 1 and is 3.% (by mass) HOH H OH. What is the molar concentration of HOH H OH in this solution? mol L mol L mol L 1 The molar mass of HOH H OH is g mol 1. * 5.43 mol L mol L 1 8 / HM 13 NWS XM 005 UNIVRSITY OF WTRLOO

9 T SHT HM 13 NWS XM 005 TH RFULLY H Li Na K Rb s Fr (3) 4 e Mg a Sr a Ra Sc Y La c Ti Zr Hf Rf V Nb Ta b r Mo W Sg Mn Tc (98) 75 Re h 8 6 Fe Ru Os Hs o Rh Ir Mt 10 8 Ni Pd Pt Uun u g u Uuu 1 30 Zn d Hg Uub l Ga In Tl Uut Si Ge Sn Pb N P s Sb i O S Se Te Po (09) F l r I t (10) 18 8 He Ne r Kr Xe Rn () 58 e Th Pr Pa Nd U Pm (145) 93 Np Sm Pu (44) 63 u m (43) 64 Gd m (47) 65 Tb k (47) 66 y f (51) 67 Ho s (5) 68 r Fm (57) 69 Tm Md (58) 70 Yb No (59) 71 Lu Lr (60) onstants: onversion factors: N = mol 1 1 atm = kpa = 760 torr = 760 mm Hg R = atm L K 1 mol 1 0 o = K = kpa L K 1 mol 1 = J K 1 mol 1 K w = (at 98 K) F = mol 1 quations: PV = nrt k t 1/ = ph = pk a + log ( [base] / [acid] ) b± b 4ac x = a 005 UNIVRSITY OF WTRLOO HM 13 NWS XM / 9