A. 1.00 B. 4.00 C. 7.00 D. 13.00
2. How many moles of H2SO4 are required to titrate 100.0 mL of 0.240 M KOH to the equivalence point?
A. 0.0480 B. 0.0360 C. 0.0120 D. 0.0240
3. Which of the following pairs cannot be used to form a buffer solution?
A. NaHSO3 and Na2SO3 B. NaOCl and NaCl C. NH3 and NH4Cl D. NaH2PO4 and Na2HPO4
4. Which of the following describes the following titration curve?
5. What is the pH of a buffer solution which is 0.250 M in benzoic acid, C6H5COOH, and 0.150 M in sodium benzoate, C6H5COONa, if Ka for benzoic acid is 6.5 x 10-5 ?
A. 3.40 B. 3.97 C. 4.19 D. 4.41
6. A buffer was prepared with a pH of 5.20. If the solution contains 0.400 moles of CH3COOH (acetic acid) per liter, what is the concentration of CH3COO- (acetate ion) in the buffer solution? Ka for CH3COOH is 1.8 x 10-5.
A. 0.400 M B. 0.139 M C. 1.14 M D. 4.74 M
7. Consider the titrations listed below. In which is the pH at the equivalence point described incorrectly?
acid base pH at equiv. pt.
A. CH3COOH NaOH > 7.00 B. HNO3 Ca(OH)2 = 7.00 C. HCl NH3 < 7.00 D. HF NaOH < 7.00
8. Which of the following statements is false?
A. A titration calculation is similar to a limiting reactant stoichiometric calculation. B. In the titration of a strong acid with a strong base, there is a sudden change in pH at the equivalence point. C. When a weak acid is partially neutralized by a strong base, the titration reaction produces a buffer system. D. The pH at the equivalence point in any titration is 7.00.
9. Imagine an indicator HIn that is red in strong acid and green in strong base. KIn = 4.0 x 10-5. Which of the following statements is false?
A. The color of the HIn molecule is red. B. The color of the In- ion is green. C. The indicator changes color when pH is about equal to pKIn. D. At pH = 7.00 [HIn] = [In-].
10. Ka1 and Ka2 for oxalic acid, H2C2O4, are 5.36 x 10-2 and 5.25 x 10-5, respectively. What is the equilibrium constant for the reaction
C2O42-(aq) + H2O(l) = HC2O4-(aq) + OH- (aq) ?
A. 5.36 x 10-2 B. 5.25 x 10-5 C. 1.90 x 10-10 D. 1.87 x 10-13
11. The Ka values for phosphoric acid, H3PO4
H3PO4 = H+ + H2PO4- Ka1 = 7.5 x 10-3 H2PO4- = H+ + HPO42- Ka2 = 6.2 x 10-8 HPO42- = H+ + PO43- Ka3 = 2.2 x 10-13
What is the approximate pH of a 0.1 M solution of sodium dihydrogenphosphate (i.e., the salt containing Na+ cations and H2PO4- anions)?
A. 0.0 - 3.0 B. 3.1 - 6.9 C. 7.0 - 11.0 D. 11.1 - 14.0
12. Which of the following substances will be more soluble in a solution of nitric acid than in pure water?
A. PbCl2 B. NaI C. BaF2 D. ZnBr2
13. How much work is done when 2.00 mol Ca reacts with excess HCl(aq) according to the following reaction? Assume that P = 1.00 atm and the molar volume of the gas is 20.0 L.
Ca(s) + 2 HCl(aq) ---> H2(g) + CaCl2(aq)
A. (2.00)(1.00)(20.0) L atm B. (1.00)(20.0)/(2.00) L atm C. (2.00)(1.00)(20.0/(8.314) J D. (1.00)(20.0)(8.314)/(2.00) J
14. Which of the following is a false statement?
A. delta E = q + w B. delta Esystem = delta Esurroundings C. Work is directed motion; heat is random motion. D. The heat content of a fuel can be completely converted into work.
15. For which of the following does delta H for the reaction as written correspond to the heat of formation of the compound on the right?
A. S(s) + O3(g) = SO3(g) B. 2 H2(g) + O2(g) = 2 H2O(l) C. SO2(g) + 1/2 O2(g) = SO3(g) D. H2(g) + O2(g) = H2O2(l)
16. Given the data shown calculate delta Ho for the reaction
3 SO2(g) + O3(g) = 3 SO3(g) delta Hfo (kJ/mol) _________ O2(g) 0 A. delta H = -439.37 kJ O(g) 249.17 B. delta H = -296.67 kJ O3(g) 142.70 C. delta H = -241.59 kJ SO2(g) -296.83 D. delta H = 153.59 kJ SO3(g) -395.72
17. For which of the following is delta S expected to be positive?
A. NH3(g) + HCl(g) = NH4Cl(s) B. CuO(s) + H2(g) = Cu(s) + H2O(l) C. CaCO3(s) = CaO(s) + CO2(g) D. N2(g) + 3 H2(g) = 2 NH3(g)
18. Which of the following would not bring about an increase in entropy?
A. increase in temperature B. increase in pressure C. melting D. vaporization
19. Which of the following is always true for a spontaneous reaction?
A. The entropy of the system increases. B. delta Go > 0 C. The rate of the reaction is very fast. D. delta Suniverse > 0
20. Which of the following corresponds to a reaction that is unfavorable (i.e., NOT spontaneous) at all temperatures?
delta Ho delta So
A. < 0 < 0 B. < 0 > 0 C. > 0 < 0 D. > 0 > 0
21. For the reaction PCl5(g) = PCl3(g) + Cl2(g), delta H = + 92.5 kJ and delta So = +182 J/K at 25oC. Assume delta Ho and delta So are independent of T. At what temperatures will this reaction have delta Go < 0?
A. T > 508 K B. T < 508 K C. T > 298 K D. T < 298 K
22. For a certain chemical reaction the equilibrium constant decreases as the temperature is raised. This reaction must be
A. endothermic. B. exothermic. C. fast. D. slow.
23. If delta Gfo for the following reaction is 3.44 kJ/mol at 298 K, what is Kp at 298 K?
H2(g) + I2(s) = 2 HI(g)
(The standard state at 298 K of I2 is the solid.)
A. 0.25 B. 0.50 C. 1.0 D. 4.0
24. If delta Go = +37.2 kJ for the reaction
PCl5(g) = PCl3(g) + Cl2(g) at 438 K,
calculate delta G when PPCl5 = 0.100 atm, PPCl3 = 0.200 atm and PCl2 = 2.00 atm.
A. 32.1 kJ B. 42.2 kJ C. 50.8 kJ D. 87.7 kJ
25. For the vaporization of water
H2O(l) = H2O(g) Keq = PH2O
Calculate the vapor pressure of water at 25oC if delta Govap = 8.61 kJ/mol.
A. 0.00609 atm B. 0.0167 atm C. 0.0348 atm D. 0.0310 atm