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

Transcription

1 VOGRO XM 2010 UNIVRSITY OF WTRLOO PRTMNT OF HMISTRY 13 MY 2010 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. The names of the top 200 students will be published in the September issue of hem 13 News. 1. Print your name here: 2. 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 2 ode 3 ode 4 ode 5 ode 6 ode 7 ode 8 ode 9 Ontario, now studying Grade 11 hemistry in a nonsemestered school Ontario, now studying Grade 11 hemistry in a semestered school Ontario, Grade 11 hemistry already completed ny other Ontario student Manitoba or Saskatchewan high school student Québec high school student not used lberta or ritish olumbia high school student 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 12 Teacher arefully detach the last page. It is the ata Sheet.

2 VOGRO XM nswers 1 ompared to an electron, a proton has 5 Which of the following has a linear geometry? the same charge and about the same mass the same charge but a much greater mass O 3 NO 2 the opposite charge and much less mass * the opposite charge and a much greater mass no charge and a much smaller mass 2 rgon has three isotopes with relative atomic masses of 36.0, 38.0 and Given that the relative atomic mass of naturally occurring argon is 39.95, which of the following statements must be correct? 40 r is less abundant than 38 r. * 40 r is more abundant than either 36 r or 38 r. 38 r is more abundant than 36 r. 36 r is more abundant than 40 r. nother isotope of lesser mass must exist. 3 n incomplete equation describing the nuclear decay of boron-9 is given below. How many neutrons or protons are also produced? e +? one neutron * one proton one neutron and one proton two protons two neutrons * 2 H 2 H 2 S F 2 O 6 Which of the following elements has properties that most closely resemble those of calcium, a? sodium, Na potassium, K * magnesium, Mg bromine, r krypton, Kr 7 What is the formula of lead(ii) nitrate? Pb 3 N 2 Pb 2 N 3 Pb 2 NO 3 * Pb(NO 3 ) 2 PbNO 3 8 Which of the following reacts with moisture in the air to form acid rain? * sulfur trioxide, SO 3 nitrogen, N 2 carbon dioxide, O 2 methane, H 4 ozone, O 3 4 When 50.0 ml of water and 50.0 ml of ethanol are mixed, the total volume is found to be 96.5 ml. What is the density of this water-ethanol solution? 1.78 g/ml g/ml g/ml 3.45 ml * g/ml ensities, in g/ml: Water, 1.00 thanol, Which of the following is an example of chemical change? boiling water dissolving alcohol in water heating copper metal compressing a gas * rusting of iron 2 / VOGRO XM 2010 UNIVRSITY OF WTRLOO

3 10 What is [Na + ] in a solution obtained by mixing 50.0 ml of mol/l NaNO 3 (aq) and 25.0 ml of mol/l Na 2 O 3 (aq)? * mol L mol L mol L mol L mol L 1 11 What is the mass of 0.67 mol Na? 29 mg * 15 g 10 g 23 g 0.67 g 12 One litre of oxygen gas is compared to one litre of carbon dioxide gas, both at 25 o and 100 kpa. Which statement is correct? The density of the oxygen gas is greater than that of the carbon dioxide gas. On average, the kinetic energy of a carbon dioxide molecule is greater than that of an oxygen molecule. 14 In an experiment, 16.0 g SO 2 is treated with 6.0 g O 2 and 18.0 g SO 3 is obtained. balanced chemical equation for the reaction is given below. 2 SO 2 (g) + O 2 (g) 2 SO 3 (g) What is the percentage yield of SO 3 in this experiment? 25% 38% 67% 60% * 75% 15 What amount of 8 H 10 O 2 N 4 contains the same number of atoms as 2 mol O 2? 2 mol 8 mol 4 mol * 0.25 mol 0.5 mol 16 In which region of the periodic table would you find the elements of highest electronegativity? top, left Molar masses (in g/mol) SO O SO Using the molar masses given, the correct answer is. However, the molar mass given for SO 3 is wrong. Question 14 was deleted. On average, a carbon dioxide molecule moves faster than does an oxygen molecule. On average, the kinetic energy of carbon dioxide molecule is less than that of an oxygen molecule. * top, right near the middle bottom, left * The two samples contain the same number of molecules. bottom, right 13 What is the net ionic equation for the reaction of Na 2 O 3 (aq) and al 2 (aq)? Na + (aq) + l (aq) Nal(s) Na 2 O 3 (aq) + al 2 (aq) 2 Nal(aq) + ao 3 (s) a + (aq) + O 3 (aq) ao 3 (s) * a 2+ (aq) + O 3 2 (aq) ao 3 (s) 2 Na + (aq) + O 3 2 (aq) O 2 (g) + Na 2 O(s) 17 Which of the following has an odd-number of electrons? NO 3 * NO 2 N 2 O NO + NO UNIVRSITY OF WTRLOO VOGRO XM / 3

4 18 What is the correct electron arrangement for a scandium (Sc) atom? (The first number in each list refers to the number of electrons in the first shell; the second number refers to the number of electrons in the second shell; and so on.) * 2, 8, 9, 2 2, 8, 2, 8, 1 2, 8, 8, 3 10, 10, 1 4, 4, 4, 4, L cylinder containing neon gas with a measured pressure of 550 kpa at 298 K is connected through a valve to a 2.50 L cylinder containing 275 kpa of helium gas at 298 K. The valve is opened and the gases mix with no change in temperature. What is the final total pressure in the system? 277 kpa 326 kpa 413 kpa * 495 kpa 599 kpa 20 What is the H-N-H angle in the NH 3 molecule? hoose the closest value. 45 o 90 o * 109 o 120 o 22 onsider the Lewis structure below for the H 3 H molecule. H What is the maximum number of atoms that can lie in the same plane? three four * five six seven 23 The following ions all have the same number of electrons. O 2, F, Na +, Mg 2+ In which of following lists are these ions arranged in order of increasing radius (from smallest to largest)? O 2 < F < Na + < Mg 2+ * Mg 2+ < Na + < F < O 2 H Na + < Mg 2+ < O 2 < F Mg 2+ < Na + < O 2 < F F < O 2 < Na + < Mg 2+ H 24 Which of the following is not a ronsted-lowry conjugate acid-base pair? H 180 o NH 3 and NH 2 21 Which of the following molecules has the strongest carbon-carbon bond? OH and O 2 * H 3 O + and OH ethanol, H 3 H 2 OH Hl and l ethanoic acid, H 3 O 2 H NH 4 + and NH 3 ethane, 2 H 6 ethene, 2 H 4 * ethyne, 2 H 2 4 / VOGRO XM 2010 UNIVRSITY OF WTRLOO

5 g sample of acid HX requires 25.4 ml of mol/l NaOH(aq) for complete reaction. What is the molar mass of the acid? 42.3 g/mol 68.4 g/mol * 98.4 g/mol 121 g/mol 29 In March of this year, the International Union of Pure and pplied hemistry (IUP) officially approved the name and atomic symbol (n) for element 112. What is the official name of element 112? * copernicium californium cupenium cernium 84.6 g/mol cuternium 26 What is the density of carbon dioxide gas at 0.00 o and kpa? * 1.96 g/l g/l 22.4 g/l 44.6 g/l 30 lement 114 would be placed directly below lead (element 82). t the present time, nuclear scientists have managed to synthesize only a few atoms of element 114 at any one time and thus, the physical appearance of a larger sample is not yet known. ased on its position in the periodic table, element 114 is most likely to be a reddish-brown volatile liquid g/l a pale yellow green gas 27 n element M forms an ion M 3+. The atom M and the ion M 3+ have the same a colourless crystal * a gray-silvery metal * number of protons a black powdery solid number of electrons radius 31 Sodium hydroxide, NaOH, is most likely found in which household product? ionization energy vinegar chemical properties soap 28 Methanoic acid, HOOH, is a weak electrolyte. In a solution prepared by dissolving 0.10 mol HOOH in water to make 1.0 L of solution, approximately 4.1% of the HOOH molecules ionize. What is the ph of this solution? bleach window cleaner * drain cleaner * UNIVRSITY OF WTRLOO VOGRO XM / 5

6 32 balloon was filled with helium gas to a volume of 3.0 L on a day when the atmospheric pressure was 101 kpa and the temperature was 31 o. The following day, the atmospheric pressure and temperature were measured as 98.3 kpa and 33 o, respectively. The volume of the balloon had not changed. Which of the following statements is consistent with these data? 35 ompared to a chlorine atom, a sodium atom has a larger * radius mass number of electrons ased on the changes in pressure and temperature that occurred, the volume of the balloon would not be expected to change. ionization energy electronegativity The balloon absorbed some air from the atmosphere. * Some helium gas leaked out of the balloon. Helium atoms in the balloon lost energy to the surroundings. 36 Which of the following bonds has the greatest ionic character? H O H ased on the changes in pressure and temperature that occurred, the volume of the balloon should have decreased. O F * H F 33 To prepare exactly 250 ml of 0.10 mol/l Hl(aq) starting from 1.0 L of 0.20 mol/l Hl(aq), one should O slowly add exactly 125 ml of 0.20 mol/l Hl(aq) to exactly 125 ml of water. * slowly add exactly 125 ml of 0.20 mol/l Hl(aq) to about 100 ml of water and then dilute with water to a total volume of 250 ml. evaporate 750 ml of water from 1.0 L of 0.20 mol/l Hl(aq). slowly add exactly 125 ml of water to exactly 125 ml of 0.20 mol/l Hl(aq). add 750 ml of 0.10 mol/l NaOH to 1.0 L of 0.20 mol/l Hl(aq). 34 Which of the following dilute solutions would allow a chemist to distinguish between dilute solutions of Nal(aq) and NaNO 3 (aq)? NaOH(aq) Hl(aq) 37 compound is found to be 85.62% carbon by mass and 14.38% hydrogen. What is the simplest formula of this compound? H * H 2 H 3 H 4 3 H 4 38 Mercury(II) sulfide, HgS, is practically insoluble in pure water. Its solubility at 25 o is probably no more than g/l. Of the following quantities of pure water, which is the smallest quantity that could be used to make a saturated solution of HgS? 20,000 L 1000 L 10,000 L For question 33, the intended answer was, but the volume of water was mistakenly given as 200 ml when 100 ml is what was intended. Question 33 was deleted. nswer is not the correct answer because 125 ml of Hl(aq) and 125 ml of water may not give exactly 250 ml of solution because volumes are not exactly additive. See question 4 for an extreme example. Molar masses (in g/mol) Hg S NH 3 (aq) * 2000 L H 2 SO 4 (aq) 200 L * gno 3 (aq) 6 / VOGRO XM 2010 UNIVRSITY OF WTRLOO

7 39 What is the ph of a solution prepared by mixing 50.0 ml of mol/l Hl(aq) and 50.0 ml of mol/l a(oh) 2 (aq)? ssume the temperature is 25 o K w = at 25 o * onsider the Lewis structure below. What is the charge on this molecule or ion? F r F 2 * UNIVRSITY OF WTRLOO VOGRO XM / 7

8 T SHT VOGRO XM 2010 TH RFULLY H Li Na K Rb s Fr (223) e Mg a Sr a Ra Sc Y La-Lu c-lr Ti Zr Hf Rf V Nb Ta b r Mo W Sg Mn Tc (98) 75 Re h 8 26 Fe Ru Os Hs o Rh Ir Mt Ni Pd Pt s u g u Sg Zn d Hg n l Ga In Tl Si Ge Sn Pb N P s Sb i O S Se Te Po (209) F l r I t (210) He Ne r Kr Xe Rn (222) 57 La c e Th Pr Pa Nd U Pm (145) 93 Np Sm Pu (244) 63 u m (243) 64 Gd m (247) 65 Tb k (247) 66 y f (251) 67 Ho s (252) 68 r Fm (257) 69 Tm Md (258) 70 Yb No (259) 71 Lu Lr (260) 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 298 K) F = mol 1 quations: PV = nrt k t 1/2 = ph = pk a + log ( [base] / [acid] ) 2 b b 4ac x 2a 8 / VOGRO XM 2010 UNIVRSITY OF WTRLOO