1. Which expression below correctly shows the equilibrium expression for the reaction: 2FeCl 3 (s) + 3 O (g) ---> Fe 2 O 3 (s) + 6 HCl (g) A. HCl 6 O 3 2 FeCl 3 B. O 3 2 FeCl 3 HCl 6 Fe 2 O 3 C. Fe 2 O 3 HCl 6 O 3 2 FeCl 3 D. HCl 6 O 3 E. None of these is correct 2. A solution is made by mixing 12.0 ml of ethanol in 100 ml of water.which of the following statements is correct regarding the solution. A. ethanol is the solvent B. water is the solute C. this is NOT a solution because they are not miscible D. ethanol is the solute E. the solution is 10.7% water by weight 3. For the following reaction: 2 A + 3 B --> C + 1/2 D + 2 E the rate, with respect to A, was experimentally determined to be 0.0185 Mmin -1. What would the rate be with respect to D? A. 0.0185 Mmin -1 B. 0.00925 Mmin -1 C. 0.00463 Mmin -1 D. 0.037 Mmin -1 E. 0.074 Mmin -1 4. An aqueous solution is 12.4 M methanol, CH 3 OH, and has a density = 0.988g/mL. What is the mole fraction of methanol in the solution? A. 0.378 M B. 0.274 M C. 0.184 M D. 0.226 M E. 0.421 M Page 1
5. In the reaction shown below, A decomposes as a second order reaction with a rate constant of k= 0.25M -1 hr -1. If the initial contentration of A is, [A] 0 = 0.050M, what is the concentration of A after 5.0 hours? A B A. 21.3 M B..00013 M C..0049 M D. 0.063 M E..0471 M 6. What is [SO 2 ] in the reaction 2 SO 2 (g) + O 2 (g) <===> 2 SO 3 (g) if, at equilibrium, [O 2 ] = 0.15M, [SO 3 ] = 2.5 M and Kc = 3.0 x 10 2? A..30 M B. 0.24 M C. 0.056 M D. 0.373M E. 2.80 M 7. Which of the answers, based on the data given, shows the correct initial rate law for the reaction between chlorine and nitric oxide? 2NO (g) + Cl 2 (g) ---> 2 NOCl (g) [NO] 0 [Cl 2 ] 0 Initial Rate (mol/l) (mol/l) (M/min) 0.10 0.10 0.18 0.20 0.10 0.36 0.20 0.20 1.45 A. Rate = k[no] B. Rate = k[no][cl] C. Rate = k[no] 2 D. Rate = k[no] 2 [Cl] E. Rate = k[no][cl] 2 8. The decomposition of N 2 O 5 to form NO 2 and O 2 is a first order and has a rate constant of 5.0 x 10-5 s -1 at 25 C. What is the half life for this reaction? A. 1.39 x 10-6 s B. 7.22 x 10-5 s C. 1.4 x 10 4 s D. 6.2 x 10 5 E. There is not enough information given to answer the question Page 2
9. Which of the following statements is NOT CORRECT if the initial rate law for the reaction is as follows: Rate = k [A] 2 [B] A. The reaction is second order in A; first order in B; and third order overall B. The units of rate would be Ms -1 C. If the concentration of A were doubled, the rate would increase by a factor of 4. D. If the concentration of B were doubled, the rate would increase by a factor of 4. E. k is the rate constant 10. K p = 1.59 x 10-2 for the following reaction at 25 C, what is the correct value of K c? 2A (g) + B (g) --> C (g) A. 9.51 B. 1.59 x 10-2 C. 6.50 x 10-4 D. 0.000422 E. 16.5 11. Which of the following will NOT affect the rate of a reaction? A. changing the concentration of a reactant B. changing the temperature of the reaction flask C. adding a catalyst to the reaction flask D. changing the particle size E. all of these will affect the rate of a reaction 12. What are [I 2 ] and [I] at equilibrium at a temperature of 800K for the reaction shown below if the initial concentrations are 0.0550 M of I 2, 0.0 M of I, and Kc = 3.1 x 10-5? I 2 (g) <===> 2 I (g) A. 0.0543 M and 0.00131 M B. 0.0543 M and 0.00262 M C. 0.0541 M and 0.000653 M D. 0.0541 M and 0.00185 M E. 0.0541 M and 0.000923 M 13. If k 1 = 5.3 x 10-2 /Ms at 45 C and Ea = 43 kj/mol for a given reaction, what is the rate constant of the reaction at 105 C? A. 3.3 x 10-1 /Ms B. 0.701 /Ms C. 1.00 /Ms D..0531 /Ms E. 0.00348 /Ms Page 3
14. The vapor pressure of an aqueous sugar solution at 25.0 C is 21.4 torr. What is the mole fraction of sugar (a non-volatile solute) in the solution? The vapor pressure of water at 25.0 C is 23.8 torr. A. Χ sugar = 0.101 B. Χ sugar = 0.899 C. Χ sugar = 1.000 D. Χ sugar = 0.500 E. Χ sugar = 0.092 15. Suppose a bottle of water is sealed at 2.3 atm of pressure at 20.0 C and contains 0.00989 go 2 /100 g O. What would the solubility of O 2 be when the bottle was opened at 0.89 atm at 20.0 C? A. 0.00989 g/100g O B. 0.0256 g/100g O C. 0.00383 g/100g O D. 0.00430 g/100g O E. 0.00230 g/100g O 16. What is the value of K p for the following reaction at 298K: A (g) + B 2 (g) 2C (g) if at equilibrium the partial pressures for A = 0.75 atm, B 2 = 2.1 atm, and C = 1.50 atm. A. 0.699 B. 1.90 C. 0.680 D. 0.952 E. 1.43 17. A first order reaction is 27.0% complete in 105 s. What is the half life for the process? A. 230 s B. 210 s C. 240 s D. 220 s E. 280 s Page 4
18. Ethane, CH 3 CH 3, forms CH 3 radicals at 700 C in a first order reaction with a rate constant of k = 1.98hr -1. How much time would it take for a 1.80 mmol sample of ethane to decrease to 0.90 mmol of ethane at this temperature? A. 152 hr B. 0.45 day C. 21.0 min D. 19.8 min E. 2.86 hr 19. Calculate the molality of a solution made by mixing 6.050 g of sodium chloride into 200.00 ml of water at 25.00 C. The density of water is 0.9970 g/ml at 25.00 C. The answer is expressed to four sig figs. A. 5.2 x 10-4 m B. 2.936 m C. 0.519 m D. 0.00927 m E. 2.945 m 20. Calculate the weight percent of a solution made by mixing 6.050 g of sodium chloride into 200.00 ml of water at 25.00 C. The density of water is 0.9970 g/ml at 25.00 C. The answer is expressed to four sig figs. A. 3.025 % B. 3.034 % C. 2.945 % D. 2.936 % E. 6.068 % Page 5
Answer Key for Test Sp04 Review, 2/5/04 No. in No. on Q-Bank Test Correct Answer 14 13 1 D 12 7 2 D 13 3 3 C 12 9 4 B 13.b 6 5 E 14 15 6 D 13 1 7 E 13 15 8 C 13 13 9 D 14 7 10 A 13 5 11 E 14 11 12 A 13 11 13 B 12 3 14 A 12 5 15 C 14 5 16 E 13 9 17 A 13 7 18 C 12 2 19 C 12 1 20 C Page 1