Chemistry 12 Name Exam IV Form A Section

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1 Chemistry 1 Name Exam IV Form A Section August, Student No. IMORTANT: On the scantron (answer sheet), you MUST clearly fill your name, your student number, section number, and test form (white cover = test form A; yellow cover = test form B). Use a # pencil. There are 7 questions on this exam. Check that you have done all of the problems and filled in the first 7 bubbles on the scantron. Your score will be reported in percents (max 100%). Exam policy Hints Calculators with text-programmable memory are not allowed. Relevant data and formulas, including the periodic table, are attached at the end of this exam. Your grade will be based only on what is on the scantron form. The answer key will be posted on the web after the exam (under "News"). As you read the question, underline or circle key words to highlight them for yourself. Avoid errors from "mis-reading" the question. ay attention to units and magnitudes (decimal places) of numbers obtained from calculations. There is no penalty for guessing.

2 Chemistry 1 Exam 4 Basic Skills 1.) Which one of the following is the ground state electron configuration of Zn? a) [Kr] 4s 3d 10 b) [Ar] 4s 1 3d 10 c) [Ar] 4s 3d 10 d) [Ar] 3s 3d 10 e) [Kr] 3s 3d 10.) What is the balanced net ionic equation for precipitation of CaCO 3 when aqueous solutions of Na CO 3 and CaCl are mixed? a) Na + (aq) + CO 3 (aq) Na CO 3 (aq) b) Na + (aq) + Cl (aq) NaCl(aq) c) Na + (aq) + Cl (aq) NaCl(aq) d) Ca + (aq) + CO 3 (aq) CaCO 3 (s) e) Na CO 3 (aq) + CaCl (aq) NaCl(aq)+ CaCO3(s) 3.) Which one of the follow has 54 electrons? i ii iii a) i only b) ii only c) iii only d) i and ii e) ii and iii Ba + 18 Te 5 13 Xe ) A stock solution is prepared by adding 7.00 ml of.19 M MgCl to enough water to make 1.00 ml. What is the Cl concentration of ml of the stock solution? a) M b) M c) M d) 1.48 M e).96 M

3 5.) How many valence electrons are there in ClO 4? a) 3 b) 30 c) 9 d) 8 e) 5 6.) An ionic compound has the formula MO 4. What is the identity of M? a) Na b) Mg c) H d) Al e) Ca 7.) What are the spectator ions in the reaction between aqueous hydrochloric acid and aqueous ammonia? a) H + and NH 3 b) H +, Cl +, NH 3, and NH 4 c) Cl + and NH 4 d) H +, Cl +, and NH 4 e) Cl only 8.) ut these atoms in order of increasing size (radius). Ba O F S Mg a) O < F < S < Mg < Ba b) F < S < O < Mg < Ba c) F < O < S < Ba < Mg d) O < F < S < Ba < Mg e) F < O < S < Mg < Ba End of Basic Skills

4 9.) The value of K eq for the equilibrium H (g) + I (g) HI (g) is 54.0 at 47 C. What is the value of K eq at 47 C for the equilibrium below? HI (g) ½H (g) + ½I (g) a) 7 b) 7.35 c) d).9 x 10 3 e) 3.43 x ) A 3.8 g sample of magnesium nitride is reacted with 7.73 g of water and 3.60 g of MgO is recovered. Mg 3 N + 3H O NH 3 + 3MgO What is the percent yield of the reaction? a) 94.5% b) 78.8% c) 46.6% d) 49.4% e) 99.9% 11.) hosphorous trichloride and phosphorous pentachloride equilibrate in the presence of molecular chlorine according to the reaction: Cl 3 (g) + Cl (g) An equilibrium mixture at 450 K contains Cl 3 = 0.0 atm Cl = 0.56 atm Cl 5 = 3.45 atm What is the value of K p at this temperature? a) 66.7 b) 1.50 x 10 c) 1.78 x 10 1 d).99 e) 7.54 Cl 5 (g)

5 1.) A solution is prepared by mixing 50.0 ml of M HCl and 10.0 ml of 0.00 M NaCl. What is the molarity of chloride ion in this solution? a) 0.183M b) 8.57M c) 3.50M d) M e) 0.117M 13.) When the following equation is balanced, the coefficient of H 3 O 4 is. H 3 O 4 (aq) + NaOH (aq) Na 3 O 4 (aq) + H O (l) a) 1 b) c) 3 d) 4 e) 0 14.) In which species does sulfur have the highest oxidation number? a) S 8 (elemental form) b) H S c) SO d) H SO 3 e) K SO 4 15.) At 400 K, the equilibrium constant for the reaction below is K p = 7.0. Br (g) + Cl (g) BrCl (g) A closed vessel at 400 K is initially charged with 1.00 atm of Br (g), 1.00 atm of Cl (g), and.00 atm of BrCl(g). Which one of the statements below is true? a) The equilibrium partial pressures of Br (g), Cl (g), and BrCl(g) will be the same as the initial values. b) The equilibrium partial pressure of Br (g) will be greater than 1.00 atm. c) At equilibrium, the total pressure in the vessel will be less than the initial total pressure. d) The equilibrium partial pressure of BrCl(g) will be greater than.00 atm. e) The reaction will go to completion (i.e., all of the reactants will be used up) since initially there are equal amounts of Br (g) and Cl (g).

6 16.) Write the balanced equation for the reaction that occurs when methanol, CH 3 OH(l), is burned in air. What is the coefficient of oxygen in the balanced equation? a) 1 b) c) 3 d) 4 e) 5/ 17.) The value of ΔH for the reaction below is kj: CH 3 OH(l) CO(g) + H (g) How many kj of heat are consumed when 15.5 g of CH 3 OH (l) decomposes as shown in the equation? a) 0.48 kj b) 6.0 kj c) 1.3 x 10 kj d) 3 kj e) 8.3 kj 18.) What volume (ml) of 7.48 x 10 M perchloric acid (HClO 4 ) can be neutralized with 115 ml of 0.44 M sodium hydroxide? a) 15 ml b) 8.60 ml c) 188 ml d) 750 ml e) 375 ml 19.) For which one of the following reactions is ΔH rxn equal to the heat of formation of the product? a) N (g) + 3H (g) NH 3 (g) b) (1/)N (g) + O (g) NO (g) c) 6C(s) + 6H(g) C 6 H 6 (l) d) H 3 (g) + 4HBr(g) H 4 Br(l) e) 6C(s) + 11H O(g) C 6 H O 11 (s) 0.) Which of the following is an oxidation-reduction reaction? a) Cu(s) + AgNO 3 (aq) Ag(s) + Cu(NO3) (aq) b) HCl(aq) + NaOH(aq) H O(l) + NaCl(aq) c) AgNO 3 (aq) + HCl(aq) AgCl(s) + HNO3(aq) d) Ba(C H 3 O ) (aq) + Na SO 4 (aq) BaSO 4 (s) + NaC H 3 O (aq) e) H CO 3 (aq) + Ca(NO 3 ) (aq) HNO 3 (aq) + CaCO 3 (s)

7 1.) Given the data in the table below, what is ΔH rxn for the reaction: C H 5 OH(l) + O (g) CH 3 CO H(l) + H O(l) Substance ΔH f (kj/mol) C H 4 (g) 5.3 C H 5 OH(l) 77.7 CH 3 CO H(l) H O(l) 85.8 a) 79.0 kj b) kj c) kj d) 49.6 kj e) There is insufficient information to answer this question..) Given the following bond enthalpies, estimate ΔH for the complete combustion of one mole of (CH 3 CH 3 ) in oxygen. C O 336 kj/mol O H 467 kj/mol C C 356 kj/mol O 498 kj/mol C H 416 kj/mol C=O 803 kj/mol a) 1419 kj/mol b) 648 kj/mol c) +648 kj/mol d) 838 kj/mol e) None of these are correct to within 1% of the answer. 3.) Consider the following reaction at equilibrium: NH 3 (g) N (g) + 3H (g) Which one of the following changes will cause an increase in the moles of H in the reaction container? a) The removal of some NH 3 from the reaction vessel (V and T constant) b) A decrease in the total pressure by changing the volume (T constant) c) Addition of some N to the reaction vessel (V and T constant) d) A decrease in the total volume of the reaction vessel (T constant) e) An increase in total pressure by addition of helium gas (V and T constant) roceed to next page

8 4.) Given the following reactions: H O (l) H O (g) H (g) + O (g) ΔH = kj H O (g) ΔH = kj what is the enthalpy for the decomposition (shown below) of liquid water into gaseous hydrogen and oxygen? H O (l) H (g) + O (g) a) kj b) kj c) kj d) kj e) kj 5.) The combustion of ammonia in the presence of excess oxygen yields NO and H O: 4 NH 3 (g) + 7 O (g) 4 NO (g) + 6 H O(g) If 34.0 g of ammonia is consumed, how many moles of oxygen will be consumed? a).0 moles b) 4.0 moles c) 7.0 moles d) 14 moles e) 3.5 moles 6.) What is the expression for K p for the reaction below? 4CuO(s) + CH 4 (g) CO (g) + 4Cu(s) + H O(g) CH4 a) b) CO H [ Cu] CO HO 4 [ CuO] CH4 c) d) e) CO HO CH4 CO HO CuO CH4 HO CO roceed to last page

9 7.) 7.0 g of Al are mixed with 3.0 g of O. Assuming the reaction goes to completion, how many moles of Al O 3 will form? a) moles b) moles c) 1.0 mole d).00 moles e) 1.5 moles

10 Form A 1. C. D 3. D 4. C 5. A 6. D 7. E 8. E 9. C 10. B 11. A 1. E 13. A 14. E 15. D 16. C 17. B 18. E 19. B 0. A 1. D. A, D=1/ 3. B 4. D 5. E 6. C 7. A