7. Consider the reaction coordinate diagram shown. Which statement is true? C D

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1 SPRING 2001 FINAL 1. A solution prepared by dissolving 6.54 g of a non-volatile solute in 60.0 g of water boils at C. What is the approximate molar mass of the solute? K b of H 2 O = C/m. A g/mol B g/mol C. 151 g/mol D. 295 g/mol E. 543 g/mol 2. A molar solution of sugar is separated from pure water by a membrane at 20 C. What is the osmotic pressure? A. 12 torr B. 91 torr C. 901 torr D torr E. 6.2 torr 3. Which is true? A. dipole-dipole forces are responsible for the solubility of ions in water B. the solubility of gases in liquids increases with increasing temperature C. dispersion forces are the result of distortion of the distribution of electrons in adjacent molecules D. hydrogen bonds are those present in hydrocarbons E. none of these 4. The reaction, 4 A + C => D has the mechanism below. What is the rate law? 2 A => B slow 2B + C => D fast A. rate = k[b] 2 [C] B. rate = k[a] 2 C. rate = k[a][b][c] D. rate = k[a] 4 [C] E. rate = k[a] 2 [B] 2 [C] 5. For the reaction, H 2 (g) + I 2 (g) => 2 HI(g), the rate constant for the formation of HI(g) is 2.7 x 10-4 L/mol.sec at 600 K and 3.5 x 10-3 at 650 K. Calculate the activation energy for the reaction. A. 166 kj/mol B. 83 kj/mol C. 332 kj/mol D. 475 kj/mol E. 166 kj/mol

2 6. The initial rates of reaction for 2 NO(g) + Cl 2 (g) => 2 NOCl(g) are Exp. Initial [NO] Initial [Cl 2 ] Initial rate [M sec -1 ] M M 2.27 x M M 4.55 x M M 9.08 x M M 3.63 x 10-4 What is the rate law for this reaction? A. rate = k[no][cl 2 ] B. rate = k[no][cl 2 ] 2 C. rate = k[no] 2 D. rate = k[no] 2 [Cl 2 ] E. rate = k[no] 2 [Cl 2 ] 2 7. Consider the reaction coordinate diagram shown. Which statement is true? B C D A A. there are three intermediates B. there are two transition states C. the first step is rate-limiting D. the reaction is endothermic E. all are false

3 8. Cobalt-60 has a half-life of 5.27 years. How long will it require for 10.5 mg of a 22.8 mg sample of 60 Co to decay? A y B y C y D y E y 9. Alpha emission by polonium-204 [ 204 Po] results in the product? A. 203 Tl B. 200 Hg C. 204 Bi D. 204 Hg E. 200 Pb 10. The actual mass of a 37 Cl atom is amu. Calculate the mass deficiency in amu/atom for a 37 Cl atom. Mass of an electron = amu, a proton = amu, a neutron = amu. A B C D E A positron has a mass number of, a charge of and a mass equal to that of a (an) : A. 0, 1+, electron B. 0, 1+, proton C. 1, 2+, proton D. 4, 2+, helium nucleus E. 1, 2+, electron 12. A buffer solution is prepared that is 0.24 M NH 3 and 0.20 M NH 4 Cl. What is the ph of this buffer? K b for NH 3 is 1.8 x 10-5 A B. 9.0 C D. 1.8 x 10-5 E. 9.33

4 13. Of the salts shown below, which ones form a basic aqueous solution? I. NaCH 3 CO 2 II. NaCN III. NaF IV. NH 4 NO 3 A. I and II only B. I, II and III only C. II and III only D. IV only E. I, II, III and IV 14. Which is TRUE? A. In the Lewis theory, BF 3 is an acid B. In a solution of H 3 PO 4, the ph is greatly influenced by K a2 and K a3? C. In the Bronsted-Lowry theory, an acid is a donor of electrons D. In water, the salt of a weak acid and a weak base has a ph Of 7.0 E. all of these are false 15. The conjugate base of HPO 4 2- is A. PO 4 3- B. H 2 PO 4 - C. HPO 4 2- D. H 3 PO 4 E. PO For the gas phase reaction, SO 2 + 1/2 O 2 <=> SO 3, ΔH = -160 kj for the forward reaction. In order to increase the yield of SO 3, the reaction should be run A. at low P, low T B. at low P, high T C. at high P, low T D. at high P, high T E. at high P, but is independent of T 17. If ml of a M aqueous NH 3 solution is mixed with ml of M aqueous HCl at 25 C, the resulting solution will have a ph = A. > 7.00 B. < 7.00 C D. cannot be predicted from the information E. none of these 18. Given that K p = 1.39 at 400 C for the reaction, P 4 (g) <=> 2 P 2 (g), which answer best describes the situation when 1.40 mol of P 4 (g) and 1.25 mol of P 2 (g) are mixed in a 25.0 L closed container at 400 C?

5 A. Q p = 1.39, the reaction is at equilibrium B. Q p = 2.47, the reaction proceeds to the left C. Q p = , the reaction proceeds to the left D. Q p = , the reaction proceeds to the right E. Q p = 2.47, the reaction proceeds to the right 19. Given that K p = 6.0 x 10-4 for the reaction, 2 CO(g) <=> C(s) + CO 2 (g), what is the partial pressure of CO 2 (g) at equilibrium if initially 2.00 atm of CO is in contact with solid carbon? A atm B atm C atm D atm E atm 20. A M solution of an acid has a ph of Calculate the K a of the acid A. 2.4 x 10-2 B. 2.3 x 10-5 C. 2.6 x 10-5 D. 5.7 x 10-4 E. 2.4 x Which of the following K a values belongs to the strongest acid? A. 6.6 x 10-4 B. 4.6 x 10-4 C. 9.1 x 10-8 D. 3.0 x 10-8 E. this cannot be determined from the information given 22. When 0.60 mol of NH 3 is introduced into a 1 L container at 850 K, the equilibrium concentration of NH 3 is measured as 0.12 M. What is K c for the reaction, 2 NH 3 (g) <=> N 2 (g) + 3 H 2 (g)? A B C D E What is the ph of a M solution of C 6 H 5 NH 2 given that its K b is 1.50 x 10-6? A B C. 8.2

6 D E In which solution will a precipitate form? I mg of Na 2 CrO 4 (molar mass = 162 g/mol) is added to 225 ml of M AgNO 3. K sp of Ag 2 CrO 4 = 1.1 x II L M MgCl 2 and L of M NaF. K sp of MgF 2 is 3.7 x 10-8 A. I. yes II. no B. I. no II. no C. I. yes II. yes D. I. no II. yes E. insufficient information to say 25. The standard free energy change for a reaction is 36.2 kj at 298 K. Calculate the equilibrium constant. A x 10 6 B C x 10 6 D E. 2.2 x At what temperature would a reaction become spontaneous if ΔH = +119 kj and ΔS = +263 J/K? A. 452 K B. 382 K C K D. 363 K E K 27. If an electrochemical cell, Rb Rb + Na + Na has a potential of V, what is the standard reduction potential of the Rb half-cell is the Na + / Na half-reaction has a reduction potential of 2.71 V? A V B V C V D V E V 28. What is the equilibrium constant for the reaction, 2 Ag + (aq) + 2 I - (aq) <=> I 2 (s) + 2 Ag(s) for which E = V? A x 10 7

7 B x 10 3 C D x 10 8 E x The second law of thermodynamics states that A. the enthalpy of the universe is increasing B. ΔS of the universe is zero C. the total entropy of the universe is increasing D. if ΔG is positive, the reaction is spontaneous E. heat is energy 30. The reaction, A + B => C + D has an enthalpy of reaction of 104 kj and a change in entropy of 60.8 J/K at 30 C. What is ΔG and the spontaneity of the reaction? A kj, non-spontaneous B kj, spontaneous C kj, non-spontaneous D kj, non-spontaneous E kj, spontaneous 31. When the following redox equation is balanced in acidic solution using the smallest possible whole number coefficients, what is the coefficient of zinc? Zn(s) + ReO 4 - (aq) => Zn 2+ (aq) + Re(s) A. 2 B. 7 C. 8 D. 14 E Calculate ΔG for the reaction of ammonia with fluorine: 2 NH 3 (g) + 5 F 2 (g) => N 2 F 4 (g) + 6 HF(g) given that the ΔG f for NH 3 = kj/mol, for N 2 F 4 = 79.9 kj/mol and for HF = kj/mol A kj B kj C kj D kj E kj 33. Calculate the solubility of silver oxalate, Ag 2 C 2 O 4 in pure water given that the K sp = 1.0 x A. 1.4 x 10-4

8 B. 2.2 x 10-4 C. 5.4 x 10-5 D. 3.2 x 10-6 E. 1.0 x A voltaic cell consists of a Cu 2+ /Cu electrode (E red = 0.34 V) and an Au 3+ /Au electrode (E red = 1.50 V). Calculate [Au 3+ ] if [Cu 2+ ] = 1.20 M and E cell = 1.13 V. A M B M C M D. 0.2 M E. 5.0 M 35. Predict the product at the anode when electric current is passed through an aqueous solution of KI A. K(s) B. K + (aq) C. H 2 (g) D. O 2 (g) E. I 2 (s) 36. How long would it take to plate 1.5 g of gold by electrolyzing a solution of Au 3+ with a current of 2.5 amps? A. 290 s B. 58,000 s C. 880 s D. 2.3 x 10-8 s E. 500 s 37. Which one of the following statements about electrochemical cells is correct A. in a salt bridge, current is carried by cations moving towards the anode and anions moving towards the cathode B. in the external wire of a voltaic cell, electrons move from cathode to anode C. in a voltaic cell, the anode is labeled as negative D. in an electrolytic cell, oxidation occurs at the cathode E. all of these are correct 38. What is a result of the lanthanide contraction? A. A Ti atom is about the same size as a Zr atom B. A Zr atom is about the same size as a Hf atom C. A Ti atom is about the same size as a Hf atom

9 D. the periodic table gets shortened when the lanthanides are left out E. weight loss 39. Which of the following transition metal ions typically has colorless compounds? A. Fe 2+ B. Fe 3+ C. Ti 3+ D. Ti 4+ E. V Which of the following statements is TRUE? A. reactivity in transition metal groups increases as you go down the group B. most lanthanides exist as 4+ ions C. an metal in a high oxidation states has a lower electronegativity than the metal itself D. Fe is often encountered in the 8+ oxidation state E. copper can be found in a +1 oxidation state as well as +2