CHEATER SHEETER - EXAM 1 1 Which of the following is not a...

Info icon This preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
EXAM 1 1. Which of the following is not a Lewis base?(a) MeNH2 (b) H2O (c) ClO- (d) C5H5N (pyridine) (e) NH4+ 2. For pH calculations involving solutions of weak acids, it is frequently assumed that the H3O+formed by the auto-dissociation of water (10-7 M) is negligible. For which one of the following a situations is this approximation least likely to be true?(a) HA has Ka = 10-2 and the initial concentration of HA is 1.0 M.(b) HA has Ka = 10-2 and the initial concentration of HA is 0.0010 M.(c) HA has Ka = 10-9 and the initial concentration of HA is 1.0 M. (d) HA has Ka = 10-9 and the initial concentration of HA is 0.0010 M. 3. Which one of the solutions listed below has the lowest pH?(a) 0.100 M HCN(aq) (b) 0.100 M CH3CO2H(aq) (c) 0.100 M HOCl(aq)(d) 0.100 M NH4+(aq) (e) 0.100 M C5H5NH+ (aq) (pyridinium ion) 4. What is the pH of a 0.82 M HF(aq) solution?(a) 2.12 (b) 3.35 (c) 4.21 (d) 2.29 (e) 1.63 5. Which one of the following is the strongest base in aqueous solution?(a) BrO- (b) ClO- (c) IO- (d) FO- (e) ClO2 6. What is the pH of a solution prepared by dissolving 3.4 x 10-4 mol of Ca(OH)2 in 375 mLwater? (a) 11.26 (b) 10.96 (c) 8.02 (d) 9.65 (e) 11.4 7. What is the pH of a buffer prepared from 0.225 mol H3PO4 and 0.105 mol NaOH in a total volume of 1200 mL? (a) 2.20 (b) 2.08 (c) 7.20 (d) 7.14 (e) 12.31 8. How many mols of NaOH would you add to 1.00 L of 0.16 M H3PO4(aq) to form a buffer with pH = 7.20? (a) 0.36 mol (b) 0.40 mol (c) 0.16 mol (d) 0.32 mol (e) 0.24 mol 9. The following salts were dissolved in water to form 0.050 M solutions. Order these solutionsby increasing pH. KCN CaBr2 [Me2 NH2]Br NH4Br Sr(OH)2(a) KCN < CaBr2 < [Me2NH2]Br < NH4Br < Sr(OH)2 (b) NH4Br < [Me2NH2]Br < CaBr2 < KCN < Sr(OH)2 (c) NH4Br < Sr(OH)2 < KCN < CaBr2 < [Me2NH2]Br (d) [Me2NH2]Br < NH4Br < CaBr2 < KCN < Sr(OH)2 (e) CaBr2 < [Me2NH2]Br < NH4Br < Sr(OH)2 < KCN 10. Which one of the following statements is false? (a) The pH of pure water is greater than 7.0 at 60 ºC. (b) The conjugate base of HCN is CN-.(c) In pure water, pH = pOH. (d) Cu2+ is a Lewis acid. (e) HOF(aq) is a weak acid. 11 . A quantity of NaCN(s) (FW = 49.0 g/mol) was dissolved in water to form 1000 mL of solution. If the pH = 11.09, then how many grams of NaCN were dissolved? (a) 7.8 g (b) 0.40 g (c) 4.5 g (d) 3.1 g (e) 0.012 g 12. What is the equilibrium constant, Kc, for the acid-base reaction shown below? HCN + ClO- CN- + HOCl a) 1.2 x 10-7 (b) 33 (c) 0.021 (d) 4.8 x 108 (e) 50 13. Which one of the following conjugate pairs would be best suited for the formation of a buffer with pH = 6.40? (a) HNO2 / NO2- (b) CH3CO2H / CH3CO2- (c) H2PO4- / HPO42- (d) HOCl / ClO- (e) HPO42- / PO43- 14. A buffer was prepared by dissolving 0.0389 mol pyridinium chloride ([C5H5NH]Cl) and 0.0255 mol NaOH in water to form a solution with a total volume of 475 mL. What is the pH of the solution? (a) 4.99 (b) 6.21 (c) 5.13 (d) 5.04 (e) 5.51 15. To the buffer described in problem 14 is added exactly 20.0 mL 0.0500 M HCl(aq). What is the pH of the final mixture? (a) 5.46 (b) 4.85 (c) 4.90 (d) 6.00 (e) 3.35 16 . What is the base-dissociation constant, Kb, for H2PO4-?(a) 1.6 x 10-7 (b) 6.3 x 10-8 (c) 2.4 x 10-2 (d) 1.4 x 10-12 (e) 7.2 x 10-3 17. A 50.0 mL 0.0500 M HCl solution was titrated with 0.103 M NaOH(aq).
Image of page 1
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern