Chemistry HW 8 - ekk86 hw08 Holcombe(53570 This print-out...

Info icon This preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
ekk86 – hw08 – Holcombe – (53570) 1 This print-out should have 25 questions. Multiple-choice questions may continue on the next column or page – find all choices before answering. 001 10.0 points At the stoichiometric point in the titra- tion of 0.130 M HCOOH(aq) with 0.130 M KOH(aq), 1. the pH is less than 7. 2. the pH is 7.0. 3. the pH is greater than 7. correct 4. [HCO - 2 ] = 0.130 M. 5. [HCOOH] = 0.0650 M. Explanation: 002 10.0 points What is the pH at the half-stoichiometric point for the titration of 0.22 M HNO 2 (aq) with 0.01 M KOH(aq)? For HNO 2 , K a = 4 . 3 × 10 - 4 . 1. 3.37 correct 2. 7.00 3. 2.31 4. 2.16 5. 2.01 Explanation: 003 10.0 points For the titration of 50.0 mL of 0.020 M aque- ous salicylic acid with 0.020 M KOH(aq), cal- culate the pH after the addition of 55.0 mL of KOH(aq). For salycylic acid, p K a = 2.97. 1. 7.00 2. 12.30 3. 10.98 correct 4. 11.26 5. 12.02 Explanation: 004 10.0 points Consider the titration of 50.0 mL of 0.0200 M HClO(aq) with 0.100 M NaOH(aq). What is the formula of the main species in the solution after the addition of 10.0 mL of base? 1. ClO - correct 2. NaOH 3. ClO 2 4. ClOH 5. HClO 2 Explanation: 005 (part 1 of 2) 10.0 points 0 10 20 30 40 50 60 0 1 2 3 4 5 6 7 8 9 10 11 12 Titration Curve mL of NaOH pH What is the pH at the equivalence point of this titration? 1. 4 . 83 2. 2 . 92
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
ekk86 – hw08 – Holcombe – (53570) 2 3. 10 . 39 4. 3 . 88 5. 8 . 79 correct 6. 5 . 62 7. 6 . 81 Explanation: The inflection points are shown below. 0 10 20 30 40 50 60 0 1 2 3 4 5 6 7 8 9 10 11 12 Titration Curve mL of NaOH pH (17 . 5, 4 . 83) (35, 8 . 79) 006 (part 2 of 2) 10.0 points What is the p K a of this acid? 1. 10 . 39 2. 3 . 88 3. 8 . 79 4. 6 . 81 5. 2 . 92 6. 5 . 62 7. 4 . 83 correct Explanation: 007 10.0 points You have a solution that is bu ff ered at pH = 2.0 using H 3 PO 4 and H 2 PO - 4 (p K a1 = 2 . 12; p K a2 = 7 . 21; p K a3 = 12 . 68). You decide to titrate this bu ff er with a strong base. 15.0 mL are needed to reach the first equivalence point. What is the total volume of base that will have been added when the second equivalence point is reached? 1. < 30 mL 2. A second equivalence point in the titra- tion will never be observed. 3. 30 mL 4. > 30 mL correct Explanation: 008 10.0 points 50.0 mL of 0.0018 M aniline (a weak base) is titrated with 0.0048 M HNO 3 . How many mL of the acid are required to reach the equiva- lence point? 1. 133 mL 2. 18.8 mL correct 3. Need to know the K b of aniline. 4. Bad titration since HNO 3 is not a strong acid. 5. 4.21 mL Explanation: V aniline = 50 mL [Aniline] = 0.0018 M [HNO 3 ] = 0.0048 M Aniline is a monobasic base ( i.e. , it pro- duces one OH - in solution). Thus you can expect that aniline and HNO 3 will react in a one-to-one fashion.
Image of page 2
Image of page 3
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