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

Transcription

1 M 13 WS XM 2009 UIVRSITY F WTRL PRTMT F MISTRY 14 MY 2009 TIM: 75 MIUTS 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. The names of the top 200 students will be published in the September issue of hem 13 ews. 1. Print your name here: 2. Print your school name and city on your STUT RSPS sheet. 3. Select, and enter on the STUT RSPS sheet, one of the following numbers: ode 1 ode 2 ode 3 ode 4 ode 5 ode 6 ode 7 ode 8 ntario, now studying Grade 12 hemistry in a nonsemestered school ntario, now studying Grade 12 hemistry in a semestered school ntario, Grade 12 hemistry already completed ny other ntario student Manitoba or Saskatchewan high school student Québec high school student Québec GP student lberta or ritish olumbia high school student ode 9 ew runswick, ewfoundland, ova Scotia, or Prince dward Island high school student ode 10 orthwest Territories, unavut, or Yukon high school student 4. Print your name (last name, first name and optional middle initial) on the STUT RSPS sheet. lso fill in the corresponding circles below your printed name. 5. arefully detach the last page. It is the datasheet. 6. ow answer the exam questions. Questions are not in order of difficulty. Indicate your choice on the STUT RSPS 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 igh school student outside anada ode 12 Teacher arefully detach the last page. It is the ata Sheet.

2 M 13 WS XM nswers 1 In the third period of the elements, how do the atomic radii of the elements vary? The radii increase steadily from a to r. 4 ow many moles of a should be added to 1.0 L of 0.10 mol L 1 (aq) to obtain a solution having a final p of 4.0 at 298 K? ssume no change in volume. (hoose the closest value.) The radii increase from a to l and decrease from l to r. There is no regular pattern. The radii decrease from a to S and increase from S to r. * The radii decrease steadily from a to r mol 1.8 mol 0.26 mol * mol mol K a = at 298 K for. 2 Which of the following compounds has the highest boiling point? l 3 5 Which of the following molecules do not form hydrogen bonds amongst themselves? 3 l 3 * l l 2 2 * F l l The reaction below reaches equilibrium in a closed reaction vessel. 4 l(aq) + Mn 2 (s) l 2 (g) (l) + Mn 2+ (aq) + 2 l (aq), Δ < 0 Which of the following actions increases the mass of l 2 (g) in the equilibrium mixture? adding some Mn 2 (s) 3 3 increasing the temperature 3 itrous acid, 2, is a weak acid in water. Which of the following statements concerning 2 is true? adding some Mnl 2 (s) * 2 is a weak base. K a = at 2 is a strong base. 298 K for 2. 2 is a weak acid. 2 is a strong acid. 2 is neither an acid nor a base. decreasing the volume of the reaction vessel * adding something that precipitates Mn 2+ 2 /M 13 WS XM 2009 UIVRSITY F WTRL

3 Use the following information and diagram to answer questions galvanic cell is constructed by placing a strip of zinc into a 1.0 mol L 1 solution of zinc nitrate and a strip of aluminum into a 1.0 mol L 1 solution of aluminum nitrate. The two metal strips are connected to a voltmeter by wires and a salt bridge connects the solutions. (See the diagram below.) The temperature is 25 o. The following standard reduction potentials apply: l 3+ (aq) + 3e o l(s) = 1.67 V Zn 2+ (aq) + 2e Zn(s) Zn(s) Voltmeter salt bridge o = 0.76 V l(s) 9 onsidering the standard reduction potentials given in the box on the right, which of the following is the strongest reducing agent under standard conditions? * l(s) l 3+ (aq) Zn(s) Zn 2+ (aq) impossible to determine 10 What is cell equal to when the cell described in the box reaches equilibrium at 25 o? 2.43 V V * 0 V 1.06 V none of the above 7 What is 0.15 V * 0.91 V 1.0 mol L 1 Zn( 3 ) 2 (aq) 2.43 V 3.49 V 6.53 V 1.0 mol L 1 l( 3 ) 3 (aq) o for the cell described above? 11 compound is 54.6%, 36.2% and 9.2% by mass. What is the empirical formula of the compound? 2 * What is the p of a mol L 1 l(aq)? In the cell described above, where does reduction occur? at the aluminum electrode * at the zinc electrode at the voltmeter in the salt bridge in the aluminum nitrate solution * less than UIVRSITY F WTRL M 13 WS XM / 3

4 13 Which of the following statements is true? single covalent bond consists of a single delocalized electron. For a bond formed between a given pair of atoms, the bond dissociation energy increases as the bond order decreases. The bond dissociation energy for a = bond is twice that of a bond. polar covalent bond results from the transfer of one or more electrons from one atom to another. * none of the above 16 onsider the thermochemical equations below. 2 4 (g) (g) 2 2 (g) (l) Δ = 1411 kj (per mol 2 4 ) 2 (s) (g) + ½ 2 (g) 2 5 (l) Δ = 278 kj (per mol 2 5 ) 2 4 (g) + 2 (l) 2 5 (l) Δ = 44 kj (per mol 2 4 ) What is Δ for the following reaction? ll the answers below are for the combustion of one mole of (l) (g) 2 2 (g) (l) 1089 kj 632 kj 14 ow many isomers are there for 5 12? 1455 kj one 1733 kj two * 1367 kj * three four more than four 15 The enthalpy change for the reaction below is Δ = 58 kj (per mole of 2 4 formed). 2 2 (g) + 2 I (aq) k (aq) + I 2 (s) k 1 If k 1 and k 1 are the rate constants for the forward and reverse reactions, respectively, and K c is the equilibrium constant for the reaction as written, then what effect does increasing the temperature have on the values of k 1, k 1 and K c? L gas cylinder contains neon gas with a measured pressure of 5.50 atm at 298 K. The 10.0-L cylinder is then connected to an empty gas cylinder of unknown volume, and the neon gas expands to fill both cylinders. If the final pressure is found to be 3.76 atm at 298 K, then what is the volume of the second cylinder? 14.6 L 6.52 L 10.0 L * 4.63 L 9.26 L k 1 increases, k 1 decreases, K c increases k 1 increases, k 1 increases, K c increases * k 1 increases, k 1 increases, K c decreases 18 Which of the following correctly describes what happens when aqueous solutions of ammonium carbonate, ( 4 ) 2 3, and potassium bromide, Kr, are mixed? k 1 increases, k 1 decreases, K c decreases r neutralizes 4 +. k 1 decreases, k 1 decreases, K c decreases K 2 3 (s) precipitates. r is formed. 4 r(s) precipitates. * none of the above 4 /M 13 WS XM 2009 UIVRSITY F WTRL

5 Use the information and diagram below to answer questions mL sample of a weak monoprotic acid,, is titrated with 0.20 mol L 1 a(aq). The titration curve is shown below. p = p = 8.91 p = 4.89 p = p 8 19 For the titration described above, which of the following is true at the equivalence point? [] = [a + ] [ ] = [] * [a + ] = [ ] [ + ] = [ ] [ ] = [ + ] 20 ased on the titration curve above, what was the concentration of the original sample solution (i.e. before the titration started)? 0.63 mol L 1 * 0.15 mol L mol L mol L mol L V a (in ml) 21 ased on the titration curve above, what is the ionization constant (K a ) for the acid,? 22 ow many unpaired electrons are there in the nickel (i) atom in its ground state electron state? * qual volumes of 0.1 mol L 1 l(aq) and 0.1 mol L 1 F(aq) are titrated in separate experiments with 0.1 mol L 1 a(aq). Which of the following would be equal for both titrations? the initial p (i.e. the p before any a is added) the p when half the acid has been neutralized (i.e. the p at the half-neutralization point) the p at the equivalence point * the volume of a required to reach the equivalence point none of the above 24 For the reaction below, K c = What is the equilibrium concentration of 3 when 1.00 mol each of Zn( 3 ) 2 and 3 are dissolved in water to make 1.0 L of solution? Zn 2+ (aq) (aq) Zn( 3 ) 2+ 4 (aq) 0 mol L mol L mol L mol L 1 * mol L * UIVRSITY F WTRL M 13 WS XM / 5

6 25 Which of the following molecules is polar? S 2 * 2 l 4 29 The unbalanced chemical equation for the oxidation of Zn by 3 is given below. The reaction occurs in aqueous basic solution. Zn + 3 Zn() ow many moles of 3 are required to oxidize exactly one mole of Zn? PF 5 1 mol S 3 * ¼ mol 26 onsider the compounds al, gl and 2 in terms of their solubilities in water. Which of these compounds exhibits an increase in solubility if the temperature is lowered and the pressure is increased? 4 mol 8 mol ⅛ mol al only gl only * 2 only al and gl al, gl and 2 27 When a 1.00 mol L 1 solution of M 2+ (aq) is electrolyzed with a current of 2.5 amperes for 0.2 hours, g of M(s) are deposited. What is the identity of M? (ote: 1 ampere = 1 s 1 )? * r Rh a Mg g 30 Two students each made four measurements of the mass of an object. Their results are shown in the table below. Student Student Measurements: 51.6 g 50.1 g 50.8 g 49.6 g 52.2 g 51.0 g 50.2 g 49.4 g verage: 51.3 g 50.0 g If the exact mass of the object is 51.0 g, then which of the following statements is true? Student s results are more accurate and more precise. Student s results are more accurate and more precise. * Student s results are more accurate but less precise. Student s results are more accurate but less precise. The two sets of results are equally precise. 28 Iron (III) oxide, Fe 2 3, reacts with hydrochloric acid to produce only water and a salt. What is the formula of the salt? * Fel 3 Fel 2 Fel 31 Which of the following compounds displays the greatest ionic character in its bonds? 2 2 * 2 3 Fe 2 l 3 Fel 6 F 2 6 /M 13 WS XM 2009 UIVRSITY F WTRL

7 32 What is the oxidation state of oxygen in F? The molecular structure of F is shown below. * zero F 33 xperiment shows that in the formamide molecule, 2, the -- angle is 119 o and the -- angle is 124 o. Which of the following structures is an acceptable structure for 2 and is consistent with the experimentally-determined bond angles? 34 Which of the following best describes the bonding in the 2 molecule? one σ bond and one π bond two σ bonds and one π bond two π bonds three π bonds * one σ bond and two π bonds 35 When building up the electron configuration of a neutral atom, which orbital fills immediately after the 5s orbital? * 4d 4f 5p 6s 5d 36 Perovskite is a mineral containing a, and Ti. The smallest repeating unit in the structure of perovskite is shown below. (There is a single titanium atom at the centre of the cube.) y considering the total number of atoms of each type that lie inside the cube below, determine the formula of perovskite. What is the formula of perovskite? ati * a 6 Ti a 8 6 Ti Ti a 2 3 Ti * a 3 Ti a 2009 UIVRSITY F WTRL M 13 WS XM / 7

8 37 onsider the Lewis structure shown below for the polyatomic ion, F 2 2. The central atom,, is an unidentified element. Which of the following atoms could represent? oxygen () * sulfur (S) bromine (r) nitrogen () F F 2 40 Which of the following is present in the greatest number in a dilute sulfuric acid ( 2 S 4 ) solution? 2 S 4 molecules S 4 ions S 4 2 ions * + ions ions xenon (Xe) 38 onsider the following reaction mechanism. ( 3 ) 3 r ( 3 ) r ( 3 ) ( 3 ) 3 3 ccording to this mechanism, ( 3 ) 3 + is a reaction product * a reaction intermediate an activated complex a catalyst a Lewis base 39 What is the final temperature when ml of water at 90.0 and ml of water at 10.0 are mixed? ssume no heat is lost to the surroundings. hoose the closest value. * 40 o 50 o 70 o 80 o Properties of water density = 1.0 g ml 1 specific heat = 4.18 J g 1 o 1 heat of vaporization = 2260 J g o 8 /M 13 WS XM 2009 UIVRSITY F WTRL

9 T ST M 13 WS XM 2009 T RFULLY Li a K Rb s Fr (223) e Mg a Sr a Ra Sc Y La c Ti Zr f Rf V b Ta b r Mo W Sg Mn Tc (98) 75 Re h 8 26 Fe Ru s s o Rh Ir Mt i Pd Pt Uun u g u Uuu Zn d g Uub l Ga In Tl Uut Si Ge Sn Pb P s Sb i S Se Te Po (209) F l r I t (210) e e r Kr Xe Rn (222) 58 e Th Pr Pa d U Pm (145) 93 p Sm Pu (244) 63 u m (243) 64 Gd m (247) 65 Tb k (247) 66 y f (251) 67 o s (252) 68 r Fm (257) 69 Tm Md (258) 70 Yb o (259) 71 Lu Lr (260) onstants: onversion factors: = mol 1 1 atm = kpa = 760 torr = 760 mm g R = atm L K 1 mol 1 0 o = K = kpa L K 1 mol 1 = J K 1 mol 1 K w = (at 298 K) F = mol 1 quations: PV = nrt k t 1/2 = p = pk a + log ( [base] / [acid] ) 2 b± b 4ac x = 2a 2009 UIVRSITY F WTRL M 13 WS XM / 9