Chemistry 47.5 Name:
First Long Examination Student ID:
2nd Semester 2010‐11 MULTIPLE CHOICE: Select the choice that best answers the questions. Mark it clearly on your answer sheet. 1. Which is the formula for hydronium ion? A) OH‐ C) H2O E) H3O‐ B) H3O D) H3O+ 2. In the reaction H2CO3 + H2O  HCO3 + H3O+, the Brønsted acids are A) H2CO3 and H2O B) HCO3‐ and H2CO3 C) H2O and H3O+ D) H3O+ and H2CO3 E) H2O and HCO3‐ 3. Identify the conjugate base of HSO4 – in the following reaction: H2PO4 + HSO4  H3PO4 + SO42 A) H2PO4‐ B) H2SO4 C) H2O D) H3PO4 E) SO42‐ 4. Which one of the following statements about strong acids is true? A) All strong acids have H atoms bonded to electronegative oxygen atoms. B) Strong acids are 100% ionized in water. C) The conjugate base of a strong acid is itself a strong base. D) Strong acids are very concentrated acids. E) Strong acids produce solutions with a higher pH than weak acids. 5. What is the concentration of H3O+ in a 2.5 M HCl solution? A) 0 B) 2.5 M C) < 2.5M D) 5.0 M E) 10.0
M 6. Calculate the pH of a beer in which the hydrogen ion concentration is 6.3  105 M. A) 4.8 B) 4.2 C) 5.63 D) 9.8 E) 14.0 7. Calculate the pH a 8.8  104 M Ca(OH)2 solution. A) 3.06 B) 2.74 C) 10.66 D) 10.96 E) 12.24 8. A 0.14 M HNO2 solution is 5.7% ionized. Calculate the H+ ion concentration. A) 8.0  103 M B) 0.057 M C) 0.13 M D) 0.14 M E) 0.80
9. Determine the pH of a KOH solution made by mixing 0.251 g KOH with enough water to make 1.00  102 mL of solution. A) 1.35 B) 2.35 C) 7.00 D) 11.65 E) 12.65 10. Diet cola drinks have a pH of about 3.0, while milk has a pH of about 7.0. How many times greater is the H3O+ concentration in diet cola than in milk? A) 2.3 times higher in diet cola than in milk B) 400 times higher in diet cola than in milk C) 0.43 times higher in diet cola than in milk D) 1,000 times higher in diet cola than in milk E) 10,000 times higher in diet cola than in milk 11. What is the pH of a solution prepared by mixing 10.0 mL of a strong acid solution with pH = 2.00 and 10.0 mL of a strong acid solution with pH = 6.00? A) 2.0 B) 2.3 C) 4.0 D) 6.0 E) 8.0 12. Which one of the following responses is true with regard to a 0.1 M solution of a weak acid HA? A) [H3O+] > [A] B) pH = 1.0 D) pH > 1.0 C) [H+] < [A] 
+
E) [OH ] > [H3O ] 13. Acid strength increases in the series: HCN < HF < HSO4. Which of the following species is the strongest base? A) H2SO4 B) SO42 
C) F D) CN  E) HSO4 14. Arrange the acids HOCl, HClO3, and HClO2 in order of increasing acid strength. A) HOCl < HClO3 < HClO2 B) HOCl < HClO2 < HClO3 C) HClO2 < HOCl < HClO3 D) HClO3 < HOCl < HClO2 E) HClO3 < HClO2 < HOCl 21. Calculate the pH of a buffer solution that contains 0.25 M benzoic acid (C6H5CO2H) and 0.15 M sodium benzoate (C6H5COONa). [Ka = 6.5  105 for benzoic acid] A) 3.97 B) 4.83 C) 4.19 D) 3.40 E) 4.41 15. Arrange the acids H2Se, H2Te, and H2S in order of increasing acid strength. A) H2S < H2Se < H2Te B) H2S < H2Te < H2Se C) H2Te < H2S < H2Se D) H2Se < H2S < H2Te E) H2Se < H2Te < H2S 22. The Ksp value for lead(II) chloride is 2.4  104. What is the molar solubility of lead(II) chloride? A) 2.4  104 mol/L B) 6.2  102 mol/L C) 7.7  103 mol/L D) 3.9  102 mol/L E) 6.0  105 mol/L 16. For H3PO4, Ka1 = 7.3  103, Ka2 = 6.2  106, and Ka3 = 4.8  1013. An aqueous solution of NaH2PO4 therefore would be A) acidic B) basic C) nuetral D) caustic E) can not be determined 23. The solubility of strontium carbonate is 0.0011 g/100 mL at 20oC. Calculate the Ksp value for this compound. A) 7.5  105 B) 1.5  104 C) 5.6  109 D) 7.5  106 3
E) 1.5  10 17. In 0.10 M KCN, the chemical species with the highest concentration (except H2O) is A) Na+ B) CN‐ ‐
D) H3O+ C) OH +
E) K 18. Which one of the following salts will form a basic solution upon dissolving in water? A) NaCl B) NaNO2 C) NH4NO3 D) KBr E) Na2SO4 F) 19. In which one of the following solutions will acetic acid have the greatest percent ionization? A) 0.1 M CH3COOH B) 0.1 M CH3COOH dissolved in 1.0 M HCl C) 0.1 M CH3COOH plus 0.1 M CH3COONa D) 0.1 M CH3COOH plus 0.2 M CH3COONa E) All solutions will have the same % ionization 20. Which one of the following is a buffer solution? A) 0.40 M HCN and 0.10 KCN B) 0.20 M CH3COOH C) 1.0 M HNO3 and 1.0 M NaNO3 D) 0.10 M KCN E) 0.50 M HCl and 0.10 NaCl 24. The solubility product expression for the dissolution of calcium phosphate is: A) Ksp = [Ca 2+ ][PO43‐] B) Ksp = [Ca 2+ ]2[PO43‐] C) Ksp = [Ca 2+ ]2[PO43‐]3 D) Ksp = [Ca 2+ ]3[PO43‐]2 E) Ksp = [Ca 2+ ][PO43‐]2 25. Fe(OH)3 is a sparingly soluble salt. In which of the following will its solubility be greatest? A) pure water B) 0.01 M NaOH C) 0.01 M HCl D) 0.01 M Fe(NO3)3 E) 0.01 M NaCl ‐‐‐ END OF PART I ‐‐‐